The Secrets of Building a Plastic Vacuum Forming Machine

Forming Machine IVincent Gingery

THE SECRETS OF BUILDING A PLASTIC VACUUM FORMING MACHINE

Written & Illustrated by Vincent R. Gingery

Published by David J. Gingery Publishing LLC P.O. Box 318 Rogersville, MO 65742

Printed in the USA

CONTENTS

First Edition

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4. How vacuum forming is done . . . . . . . . . . . . . . . . . . . . . . . . .7 . Vacuum form safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 . A few things to consider . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

First Printing 1999

Copyright

1999 Vincent R . Gingery All rights reserved @

What kind of plastic can we use and where can we buy it? . . . . . 16 . What is vacuum? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 . Choosing a vacuum source . . . . . . . . . . . . . . . . . . . . . . . . . 18 . Vacuum storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 The heating element and control switch . . . . . . . . . . . . . . . . .22

Library Of Congress Catalog Card Number 99-94589

ISBN # 1-878087-22-3

.

~p

NOTICE OF DISCLAIMER: There are serious hazards in the processes and procedures in this book . No attempt has been made to point out all of the danger or even a majority of them . The methods. materials and procedures that are suggested in this manual were developed by a nonprofessional. The author is not an engineer or scientist and no claim is made to the propriety of the methods suggested in these pages . The reader is fully responsible for developing save procedures for every operation. Both the author and David J . Gingery Publishing hereby disclaim any liability for injury to persons or property that may result while using this book . Neither intends by this publication to explain all dangers known or unknown that may exist in the building and operation of the project.

The adjustable platen . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 . Other materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 . Tools & construction methods . . . . . . . . . . . . . . . . . . . . . . .26 . Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 . Material list for roll around cart . . . . . . . . . . . . . . . . . . . . . . 26 . Building the roll around cart . . . . . . . . . . . . . . . . . . . . . . . . 28 . Mounting the platen jack and control valves . . . . . . . . . . . . . . . 36 Parts list for the adjustable platen assembly . . . . . . . . . . . . . . . .41 Building the adjustable platen . . . . . . . . . . . . . . . . . . . . . . . .42 Parts list for clamp frame . . . . . . . . . . . . . . . . . . . . . . . . . . .57 . Building the clamp frame . . . . . . . . . . . . . . . . . . . . . . . . . . .58 Material list for heater . . . . . . . . . . . . . . . . . . . . . . . . . . . .66. . Building the heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67 Wiring material list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81 Wiring the machine &building the control panel . . . . . . . . . . . .82

. Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vacuum molds 92 . Final thoughts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103 sources

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 .

Introduction The term Vac~turnForming describes a process of forming sheet plastic into simple shapes. This is done by heating a sheet of thermoplastic until it is soft and pliable and then placing it over a mold forminga tight seal between the mold and the plastic. Thena vacuum is applied through small holes in the mold andlor work surface that draw the softened plastic into or over the mold. As the plastic cools, it rehardens. permanently taking on the shape of the mold. Plastic vacuum forming machines that perform this process can range in size from small table top models to huge industrial machines costing many thousands of dollars. When I first became interested in vacuum forming plastic :.......+.lii~i;:;; s ; ~ s ; ; z . . .. ...v.. . - .. . I did some research to find if I ' ' . .. . . 1. , there were plans available for constructing a vacuum forming machine. I came across a few. many of which used a vacuum cleaner as the vacuum source and the kitchen oven as a heat : source to soften the plastic. One i good idea for a small machine used an electric skillet as the heat source with a clamp frame hinged to a vacuum box. Both were set side by side. When the plastic was softened, the frame holding the plastic was flipped iI over the mold which rested on the vacuum box. Vacuum was applied and the pan was i formed. All excellent ideas for forming small items in thin sheets of plastic using positive molds, but I wanted a larger more versatile machine. Something that was selfcontained and

...........

"

..

~ ~

capable of forming thicker sheets of plastic using either positive or negative molds. Anyway, to make a long story short, I set about seeing what I could put together. As I began the project I quickly realized there were a couple of hurdles to overcome. The first was to find a suitable heating element. I knew for sure I wanted the element to operate on 120 volts. After some checking, I discovered a wide array of 220 volt replacement heating elements available, but very few 120 volt elements. That's because most kitchen ovens use 220 volt elements. It was economics 101. Companies only stock what they can sell. I was finally able to locate a suitable 120 volt element through Chromalox which made this project possible. More about that later. The other hurdle was to find an inexpensive. but adequate vacuum source. There are electric vacuum pumps available that are specifically designed for the process, but they are expensive. I had seen an air venturi vacuum pump advertised by Harbor Freight to pull 4.2 cfm using an air compressor priced at $12.99. I already had the air compressor so this was encouraging. I purchased the venturi pump and it worked as advenised. Adding tanks to the machine for storing the vacuum ahead of time enabled the concept to work out very well. The air pump will pull a satisfactory vacuum of about 20 hg on both my 11 gallon storage tanks in about 3-112 to 4 minutes. Not fast enough for high production, but good enough for me considering the cost. If you are going to use the machine for large production runs where speed is important. then an electric vacuum pump with a high cubic feet per minute rating would be the way to go. We will discuss vacuum pumps a bit more later in the book. The final result of my endeavors and the subject of this book is the machine shown in figure 1. It uses a 120 volt heating element and is capable of forming 12" x IS" sheets of plastic up to 114" thick and uses both positive and negative molds. The machine shown in figure 1 is using an air venturi pump for the vacuum source, but the it is set up to easily operate with an electric vacuum pump if you so choose. The machine is built on wheels so it can be easily moved from place to place and another nice feature is the adjustable platen table making it possible to form molds of different sizes.

In the next section we will describe the machine in greater detail, and get you acquainted with the process of actually vacuum forming a sheet of plastic. Then it's on to building the machine and forming plastic.

C

STATIONARY LEGS

INDICAIOR LIGHT

IF ONE IS USED.

HCATCR CONTROL INDlCAlOR LIGHT VACUUM GAUGE

POWCR OUTLET CONTROLLED

Figure 2

How vacuum forming is done Before learning how vacuum forming is done, we need to learn a little bit about the machine. The detailed drawing in figure 2 shows the main features of the machine. The 4 photos in figures 3-6 show the front, rear and side views of the machine. The machine is built around a sturdy roll around cart made of 118" x 1-112" angle iron. The bottom shelf of the machine is large enough to hold two 11 gallon vacuum storage tanks and a vacuum pump. The storage tanks are portable air tanks that have been converted to our purpose. The machine operates on a 20 amp, 120 volt AC circuit. The machine as shown is using a venturi vacuum pump, but an electric pump could be used as well. The control panel contains a vacuum gauge, an infinite range switch to control the heater temperature and an indicator light that shines when the heater is on. The switch on the right side of the panel activates an outlet receptacle mounted on the right front leg of the machine. If you were to use an electric vacuum pump it would plug into this outlet. The indicator light above the switch leu you know when the switch is on. The valve mounted on the left front leg of the can is used to control the incoming air supply to the venturi pump if one is used. The two valves on the top shelf of the can operate as follows: The valve on the left connects the vacuum pump directly to the storage tanks. With the valve open you can pull a vacuum on the tanks. After a vacuum has been pulled you close the valve to store the vacuum. The valve on the right opens and closes the vacuum line from the storage tanks to the platen.To form a sheet of plastic, you would open this valve. The platen is the solid surface on which the molds rest on during the vacuum forming process. Vacuum reaches the platen surface through a hole located in the center of the platen. On most vacuum forming machines I have seen. the platen is stationary, but on this machine it is adjustable. The assembly consists of the platen surface which is a solid board covered with formica or other smooth, heat resistant material. The platen surface rests on a frame built of 118" x 1-114" angle iron. Legs made of 1" square wall tubing are welded to each comer of the frame. In operation, the 1" legs on the platen

7

Figure 3 Front view of machine. The small box on the ley? side of the bottom shelf is the venturi pump. Vacuum storage tanks are in the background. Notice the trailer tonguejack mourned on the top shelf. It is used to raise and lower theplaten. 7liecontrolpanel contains the vacuum gauge on the I@, the heater control dial and indicator light in the center and on the right side of the panel is the electric vacuum pump switch and indicator light.

Figure 4 Right side view of machine. Here youget a gwd view of the plumbing, storage tanks and crank handle.

Figure 5 Rear view ofmachine. Here you can see how the cord comingfrom the heating element plugs into the cord comingfrom tlze control panel. It's a hondy feature that lets you completely remove the heater box by simply unplugging it an lifting it off rhe hinge.

Figure 6 Lep side view. Here you can clearly see rhe air supply valve mounted on the front leg. Opening the valve supplies air to the venturi pump.

table, move up and down on stationary posts made of 314" square wall tubing attached to each top comer on the roll around can. It's a nice set up because the 1" square tubing fits nicely over the 314" square tubing. The result, a table that operates smoothly and is easy to raise and lower by way of the trailer tongue jack mounted in the center of the roll around can. It's important to note that the type of jack we are using is referred to as a rack and pinion type. With this type of jack, there is a clear path through the center of the jack shaft for running a vacuum hose up to the platen. The clamp fixture mounted at the top of the unit is used to hold the plastic firmly in position during the vacuum process. It's a simple fixture made of 112" x 1" aluminum or cold roll steel bar stock. The hood at the very top of the machine contains the heating element. If you look at the side views of the machine you can just barely see the element. We are using a 15 amp, 120 volt element. The hood is fitted with a swivel hinge so it can be moved over to one side for easy access to the clamp frame. Now that we understand the machine a bit better we can actually form a sheet of plastic. The series of photos shown in figures 7 - 18 take you through the process.

Vacuum form safety

.. .

The vacuum forming process is fairly safe, but in all things, there are dangers both hidden and realized. Proceed carefully and think through each move until vou become familiar with the Vacuum forming creates some minor fumes which can be irritating, provide good ventila- Figxrc 7 7rri.c 1.r n slror qfrlrc iim(.Iriirclookirr,? doll~rtar rlrr l~lmmt.n t r rorozcl ltolo irr /Ire tion. cenrer of /lie plareir is the vacrtrrnt porr. nre mold will be centered over rhis hole.

Never leave your machine unattended during use. Pay close anention at all times because there is the danger of the plastic overheating. Overheating plastic creates a heavy smoke that can be hazardous and of course there is the added danger of the overheated plastic catching fire. Use extreme caution around the heater box! Its outside surface reaches high temperatures capable of causing bums. Treat it like you would any oven. Use the handle when moving the heater from side to side, and as an added protection, wear gloves.

Figure 8 7liis is a shor q f rlrc rrrr(l~~r~ri~~rrlr .si(li,(ofrltcmold we will be using for our demonstration. nre horrom qf rlre r~roldis recessed ro provide air space for the vacuum. Norice the large and small holes drilled into rhe mold. 7liese are vacuum draw holes [hat have been drilled through to the mold cavity. They are srrategically placed and generally locared ar those places that require the deepesr draw. There is a rubber seal glued around rhe outside botrom edge of rhe mold to prevent vacuum leaks between the mold ond platen.

Figure 9 This is a I ' I F I I . (!f rlrr i11010 (15 ir .s/r~rt/dresf centered over the vacuum port on the ploren. This panicrtlar ntokl is classified as a negarive mold which means the parrem shape is recessed in the mold.

Figure 10 Mold is it1 posiriorr on rite plaren srrrfoce and I an1 in rhe process of raising rheplaren fable.

Figure I2 The hearer is moved irl position over the ploren surfoce.

Figure I 1 A piece of SVrene p l m i c is held .sec!rre/\~in the ~IampjixIureand t l ~ platen e iable has been raised to prrsh the mold against rite surfnce ofrl~eplastic.

Figure 13 The venruri air pump is connected to an air supply. The valve i.7 placed in the open position.

Figure 14 7lle valve that opens and closes the line between the venmri pump and the storage tanks is opened and we begin pulling a vacuum on the tanks.

*Large commercial machines are automatically controlled using precise temperature indicators which indicate when to form a sheet of plastic. We don't have that convenience built into our machine. But then it's really not necessary because with a little experience we can make accurate determinations visually. In the example, I am forming a sheet of Styrene plastic that is .030thick. I will describe the visual changes that occur to the plastic during the heating process. The changes occur rapidly so you must keep your eye on things to prevent the plastic 1 from overheating klwe&we

I

I

q

As the plastic begins to heat

Figure 15 The infinite range switch that controls the hearer is turned on andpositioned on high. T h e p M c begins to heat to forming temperature. (Approximately 300 degrees)

Figure 17 Theformed plastic sheer as it looks shonly arer the vacuum has been pulled. Figure 16 When a vacuum has been pulled on the storage tanks, and theplastic sheet has *sofreneds@cienrly, the valve that connects the vacuum storage ranks to the platen is opened and the plastic is slicked into the mold. The heater is moved over to one side. The vacuum is held on the moldfor a coriple of additional seconds unril the plastic has cooled then the vacuum valve i~sturned oft:

Fi,qrrre I 8 Tlrr cu~~rplf'll~fl iirpln re11ro1~edJro111 the mold.

15

to warp in different directions. As the temperature rises further the surface quickly becomes taught, like a surface of a dmm. At this point you are very near forming temperature. Some plastics have a tendency to sag quite a bit in the frame at forming temperature, which can be a good indicator of when to form the sheet. But Styrene sags only slightly. It is a; the of slight sag that you want to form the pan. It will take careful observation to notice the sag. When you see it, form the part. It's as easy as that. There are other types of plastic that you may use such as ABS, CAB, PET-G only to name a few. Each have slightly different which you will soon become familiar with.

A few things to consider

.. .

We've had a pretty good look at the machine and now have a basic understanding of how it works. But, before designing, buying or building a vacuum forming machine, there are still a few things to consider such as: 1. What kind of plastic can we use and where can we buy it? 2. What is vacuum? 3. Choosing a vacuum source. 4. Vacuum storage. 5. The heating element and control switch. 6. The adjustable platen.

What kind of plastic can we use and where can we buy it? You will be forming your items from flat sheets of thermoplastic material. Thermoplastic simply refers to a type of plastic that can he softened by heat and reshaped by some type of pressure. There are many types and grades of thermoplastic sheet available, each having different properties. Usually, depending on the type of plastic you are using, you will be able to choose between a variety of colors and thicknesses. Depending on where you live, finding a source for plastic can be as easy as looking in the phone book under the heading, "Plastics Supply Centers". I found 4 companies in my phone book, two of which were only a few miles away. I checked with the two that were closest to my house. In both instances, these were companies that were accustomed to dealing with commercial customers. A little guy like me kind of took them by surprise. Even so, when I explained what I was doing and that I really didn't need 500 sheets of plastic they were still more than helpful. The first company was a local manufacture of plastic items and was more than happy to sell me a few smaller pieces of ABS and Stryrene that were left over from

previous jobs. Plastic generally comes in 4' x 8' sheets so I welcomed the opportunity to buy the smaller quantity. The other company I contacted was a branch office for a national company called, "Regal Plastics Supply". Since this was a national company, I listed the address of their corporate office at the back of the book. You can contact them to see if they have a store near you. They are also willing to sell by mail order. Anyway, they were equally kind and more than helpful. I purchased a single 4 x 8 sheet of ,060 black ABS and a 4' x 8' sheet of ,060 clear PET-G from them. I learned that plastic supply companies are only likely to stock types of plastic based on what the need in their immediate area is. What is easily available here may not be available or require a special order somewhere else. Expect to pay in excess of $1 .OO a square foot for most of the plastic sheets you buy. Thinner sheets of some types of plastic might cost a bit less and thicker sheets a bit more. As in anything, I am sure that prices can vary widely, so if possible comparison shop. Also, before you purchase your plastic, ask questions about its forming characteristics and if possible explain to the sales rep what you plan to use it for. They have a wealth of information available to them and often are more than willing to offer advice.

What is vacuum? One dictionary defines a vacuum as a space devoid of matter or from which air or other gas has been removed to a very high degree. Another simply says, pressure lower than atmospheric pressure. To understand vacuum a little better we must first know that air has weight. 14.7 pounds per square inch (psi) at sea level. A reading of "0" psi on a normal pressure gauge is equal to atmospheric pressure or 14.7 psi. An absolute pressure gauge registers "0" at a pressure which cannot be further reduced. In other words a perfect vacuum is "0" pounds per square inch absolute. When pulling a vacuum on a sheet of plastic one is inclined to think that suction is doing the work, when actually it is the weight of the atmosphere (14.7 psi) pushing against it that does the forming. To demonstrate it a little better, think of the space within a vacuum as a thin piece of fresh white bread weighing much less than 14.7

pounds. Place a 14.7 pound brick on the piece of bread and see if it doesn't flatten it. It's the same principle, a heavier weight object vushing- against the lighter weight bbject and forming it. In a perfect vacuum, 14.7 psi is the maximum amount of forming pressure you can achieve. There are a couple of ways of measuring vacuum. The method we will be using is inches of mercury (in. hg). This refers to the amount of vacuum that it takes to lift a column of , mercury 1 ".A mercury gauge with a ROIIRP. nti.vg(ttt,y~ r-cod.\ from vacuum at the closed top of the tube 0 psi to 30 /r
-

-

Choosing a vacuum source Removing the air from a designated space requires some type of suction. There are several ways of pulling a vacuum, but only a few are really adequate. Below is a list of some vacuum sources to consider. Vacuum cleaner: This method comes to mind first because it isan everyday appliance. Also, since most of us have a shop vac in the house it would be inexpensive. And it would work fine for light duty applications such as shallow molds using light gauge plastic. Depending on the vacuum cleaner, you can expect to pull a 3-6 hg. vacuum.

Modified air compressor: An air compressor sucks the air out of the atmosphere and stores it in a tank. A modified air compressor works just the opposite. It sucks air out of a tank and discharges it into the atmosphere. Instead of storing air pressure the compressor tank stores vacuum. To COINert an air compressor to a vacuum pump you simply tap into the suction port of the air compressor. Beware though, not all air compressors can be converted. Air venturi: These are fascinating- devices and in my opinion are an inexpensive way of pulling a vacuum. That is, if you already own an air compressor capable of delivering 90 PSI. Air venturi pumps create a vacuum by forcing compressed air through a limiting orifice into a venturi section. As the air exits the orifice it expands, increasing in velocity to supersonic speeds before entering the venturi section. This creates a vacuum or negative pressure at the vacuum inlet port. In the past air venturi pumps have Figure 20 been an expensive device. I had Air~en"'fPumP considered making one until I discovered that Harbor Freight now carries one similar to the one shown in figure 20 for $12.99. It's capable of removing 4.2 CFM @ 90psi. Mine works very well. Not as well as an electric vacuum pump, but for the price I am willing to sacrifice a little. With the air venturi pump I can pull a 20 hg vacuum on two 11 gallon tanks in a little over 4 minutes. After 20 hg, the rate slows down drastically. It will pull a deeper vacuum, but be prepared to wait a while. 20 hg was adequate for most of my applications. Generally, you won't need to pull a deeper vacuum on the tanks unless you are fonning heavy gauge plastic. In that case you might consider an electric vacuum pump with a higher cfm per minute. Even then, 25 hg is about as much as you can expect to achieve in a reasonable amount of time. The pump is referred to in the Harbor Freight catalog as a Central Pneumatic venturi type vacuum pump, Item# 03952. Check the

sources section at the back of the book for the address and phone # of Harbor Freight.

Electric vacuum pumps: These will deliver the best performance and if you are going to use your machine in a high production environment or regularly form heavy gauge plastic these may be something to consider. A look in Grainger's catalog will show you there are many to choose from, but they are expensive. The important thing to consider with any vacuum pump is the cubic feet per minute (CFM) output rating of the pump as well as its horse power rating. A higher CFM output means the pump will pull a vacuum quicker. A description of a few of the pumps available follows . . .

pump that delivers a 6 cfm output. It worked very well and pulled a 25 hr! - vacuum on my two I1 -gallon tanks in less than 2 minutes. One potential problem with this pump is that it requires frequent oil changes. As the oil absorbs moisture from the air the output performance of the pump decreases. This is no problem for light use, but it is something to consider if you plan to use the machine quite a bit. I have not had experience with the oil-less pumps that are available because of their high cost, but if I were going to put the machine to heavy use I certainly would check into them further. There are vacuum pumps designed for industrial thermoforming, but they have price tags approaching $2000.00. Ultimately, your needs and budget will have to be the determining factor.

Diaphragm pump: This type pump consists of a diaphragm that is

flexed back and forth by a shaft creating a piston like motion inside a housing. Generally these types of pumps are less expensive and are used for light duty applications. I have not seen one capable of delivering a satisfactory CFM output for vacuum forming. Piston pump: Consists of one or more pistons reciprocating inside one or more cylinders. Similar to an air compressor, except that air is discharged to the atmosphere. More expensive, but capable of delivering a satisfactory CFM output. Rotary vane, Consists of a rotor with sliding vanes rotating inside a

housing. The rotating vanes trap the air and sweep it from intake to exhaust, generating a vacuum. Capable of delivering a satisfactory CFM output. I had the Robinair high performance vacuum pump shown in figure 21 on hand before I started the project. It's a refrieeration service DUmD . . and I did some experimenting with it. It's a 2-stage electric

(,..,.......,....<... ...............,. ...

.,

Figure 21 2-srage elecrric vacuum e,iv ers a CFMolllput.

pllmp

Figtire 2.3 E~fiprypropnrrr rcrfik

Figure 24 Empty freon t ~ ~ i k

Vacuum storage None of the vacuum methods listed previously will pull enough of a vacuum quick enough on their own to form heavy gauge plastic. To aid the process we can build up vacuum in advance and store it in a tank or tanks. A few ideas for tanks that can be readily adapted for this purpose are portable air tanks, empty freon tanks, empty propane tanks. (The type used on out door barbecue grills.) See figures 22-24.

The heating element and control switch Our method of heating the plastic sheet is with radiant heat. A heating element mounted under a box and , located above the sheet of : plastic radiates heat down On Figrrre 25 Plroto of lrc~flrirr,qplrnr?rrr. the plastic. We want an 771clmrt@ rnora?ringbrflckc,rcornes wirh element that will deliver tile equal heat over the entire surface of the plastic, keeping in mind that the plastic sheet will have a tendency to absorb more heat in the center and experience a greater heat loss at the outside edges. As I mentioned in the introduction, I wanted to use a 120 volt element if at all possible. A quick glance in a pans catalog showed many oven elements available in all different sizes and s .,, ,-\ -2\ shapes, but they all required 220 volts. After some research I found one manufactured by a company called ,/sChromalox. See photo and spec drawing on this page. I E.I.~,~~.. 150514 WATTS 1500 1M514B VOLTS 120 ordered the element from them and as luck would have it turned out to be just what I Figure 26 Chromlox hearing element

-

needed.

#CH2885

It had mounting 22

brackets as a standard feature which worked out very well. The 3" spacing between element sections was just right for delivering a nice even heat over the plastic sheet. The 12" x 15" suggested capacity of the machine placed the outside elements closer to the outside edges of the plastic to help offset the heat loss that occurs in that area. Please note: The plans in this book are for building a 120 volt machine. A 220 volt machine could be built, but keep in mind that all of the wiring including the infinite range switch would be different than that shown in the book. I think that for home shop use the 120 volt model seems more practical. If you're like me and decide use a 120 volt element, you need to know that these types of elements are somewhat difficult to find without a special order. I purchased mine through Chromalox (See address in sources section) They required a minimum dollar order of $100.00 before they would ship. To make these elements more readily available I bought a quantity of them and will sell them to those who have trouble finding them elsewhere. See price & ordering- information in the sources section at the backof the book. I used an infinite range - I control switch rated 15 amps at 120 volts AC to control the ! heating element on my ma- ! chine. These type switches are readily available at appliance parts stores. They control temperature by varying the onloff time of the element. Figure 26 Sl~on,nis a I5 amp. 120 volr C11romalo.r#UC12O infinire range This is done by Of a sa,irch and dinl. Mounting lmrdware is small resistor which is wrapped in thep,astic bag, around a bi-metal arm. The bimetal arm controls a double-pole switch. The position of the dial determines the tension on the bi-metal arm to establish the setting. In the on position, current flows through the resistor and through the element. As the bi-metal arm heats up, it bends and overcomes the dial tension shutting off the current to the element. When the bimetal arm cools it straightens out and the cycle begins again. On the low setting this cycle may repeat several times in a minute. On the high setting the current to the element will remain constant.

,

.

The adjustable platen As mentioned earlier, the platen is the work surface on which the ? .. mold rests during the vacuum process. It's very beneficial to be ; able to adjust the platen up and down giving us the ability to use varying sizes of molds. It was a tough challenge coming up with a method of accomplishing this until I !;i: began looking at the crank up jack (ill*, z,..: k' mounted on my boat trailer. It 1,7,?11re 28 R(1c.k CC ~ ; I I ; O I I /r(111i,r turned out to be a perfect solution. I j(,& ro,,sr (,I, lo ,,,er purchased a similar jack and p,o,en, mounted it on the top shelf of the cart. It was a simple matter to attach the jack shaft to the platen table using a hose clamp. And it worked very well. Cranking the jack in one direction raises the table and cranking it in the opposite direction lowers the table. There are a couple of types of these jacks available. One raises and lowers using a threaded rod traveling inside a fixed nut located within the jack shaft. The other type uses a rack & pinion as shown in the photo figure 28. You will want the rack & pinion type. Both cost about the same, but the rack & pinion type is hollow through the jack shaft and you will need the hollow area to run the vacuum hose through the jack and up to the platen. I purchased my jack at a farm supply store, but later noticed that Harbor Freight had one for $19.99. The item # listed for this jack in my catalog was 37792OJEB. The address for Harbor Freight can be found in the sources section at the back of the book.

C,

i

,()

(,

Other materials The materials used to construct the machine consist mainly of angle iron, bar stock, square tubing and sheet steel. There are 2 classifications of steel that you need to be familiar with when buying your steel. Those are hot roll sreel, and cold roll steel. Most of what

you will need is hot roll steel (h.r.s.) . The exception to this rule are the materials used for the clamp assembly which can either be built of aluminum or cold roll steel (c.r.s.). The terms hot roll steel and cold roll steel refer to the way steel is processed. For instance, the surface finish on c.r.s. is smooth and its size is accurate to .003"-.005" when it leaves the mill. This makes it ideal for more exacting work such as the clamp frame on our machine. Hot roll steel on the other hand, has a surface finish that tends to be rough and scaly and is much cheaper to buy than c.r.s. making it ideal for general purpose work such as the frame of our machine. All of the material to construct the machine is easy to find if you know where to look. The best place to start looking is at a steel yard or metal scrap yard. At the steel yard, ask if you can look through the drops. Drops refer to the left over material that companies often have. These are the short ended pieces that really can't be used on other jobs and therefore companies are often glad to sell them to you at reduced prices. The main thing to keep in mind at the steel yard is to avoid the cut off fees if at all possible. This is the fee they charge to cut the material to length. Often these charges total more than the cost of material itself. If you find a piece of material longer than you need, buy the whole thing, take it home and cut it to length yourself. Add what's left to the scrap pile. You're bound to need it on the next project. Another place to look is at the lumber yard, hardware store or farm supply store. They will otien have a rack with an assortment of angle iron, and flat bar for sale. Expect to pay more at these places, but if you can't find it elsewhere they're a good place to look. There are several companies that sell metal products such as angle, flat bar and other items by mail order. I have listed the names, addresses and phone numbers of several of these companies at the back of the book. In addition to what we have already discussed you will need a few other things such as nuts & bolts. shut off valves, onloff switches etc. These items will be referred to in detail in the material list.

Tools & construction methods You will find the construction of this machine to be fairly simple requiring only the most basic tools. No advanced metal work here. Just a hacksaw or metal cutting bandsaw to cut the material to length. A drill press and an electric hand drill along with a set of drill bits from 1116" - 112" for the drilling operations. I used hole saws for drilling some of the larger holes in the machine. Sizes of hole saws needed are a 314", I", 1-1/4", 1-314" and 2". A good quality 3\8-16 tap and a 1/4-20 tap are needed. A couple of C-clamps andlor visegrips to hold the frame together while welding. A vise grip sheet metal tool, bench vise or sheet metal brake for bending metal. A rivet gun, a circular saw for cutting wood and a good quality jig saw with a metal cutting blade. You will also need a few common hand tools such as an assortment of wrenches, screw drivers, pliers etc. The most exotic equipment you will need is a welder capable of working at about 75 amps for constructing the frame.

Safety As with any project, there are dangers both hidden and realized. Keep safety in mind at all times. Not only for yourself, but for those around you. Always wear eye protection when cutting and grinding in the shop. Use an approved welding helmet when welding, and allow for plenty of ventilation. Ensure that all flammable material has been cleared from the welding area. There is some electrical wiring required in this project and it should be done only by a qualified individual and should conform to local code.

Material list for building the roll around cart 4 pieces of 118" x 1-112" x 24" h.r.s. angle iron. These are the side rails for the top and bottom frame of the cart. See figure 29. 4 more pieces of 118" x 1-112" x24" h.r.s. angle iron. These aie the end rails for the top and bottom frame of the cart. See figure 30. 4 pieces of 118" x 1-112" x 32-112" h.r.s. angle iron. The legs for the roll around cart. See figure 32.

2 pieces of 14 gauge h.r.s. sheet metal measuring 23-314" x23-314". The top and bottom shelves for the cart. See figure 34. Eight, 1/4-20 x 112" bolts with nuts &lock washers. For attaching the top and bottom shelves. See figure 36. Two, 2" stationary casters and two, 2" swivel casters. See figure 37 & 38. Eight 1/4-20 x 314" bolts, nuts & lock washers. For attaching the casters. See figure 38. 4 pieces of 114" x 2-314" x 2-314" h.r.s. flat bar. Mounting blocks for the stationary rails. See figure 39. Four, 114-20 x 314" bolts. Studs for mounting the stationary rails. See figure 39. 1 rack & pinion style trailer jack. For raising and lowering the platen table. See figure 41. 1 piece of 112-13 threaded rod 6" long. Extension shaft for the crank handle. See figure 43. One, 112-13 coupling nut. For attaching crank handle shaft extension. See figure 44. Two 118" pins, 1" long cut from a length of 118" round rod. For securing coupling nut to the crank handle shaft. See figure 45. 2, 314" ball valves. See figure 46. 4, 314" street elbows. See figure 46, Four, 114-20 x 314" bolts with nuts & lock washers. For mounting the platen jack to the top shelf of the cart. See figure 47. Two, 1-112" "U" bolts 2" long with 114-20 threaded legs. For attaching the ball valves to the top shelf of the cart. See figure 47. 1 piece of 10 gauge h.r.s sheet metal measuring 2" x 4-112". For the jack handle support bracket. See figure 48. Two 114-20 x 112" bolts with nuts. For mounting support bracket. See figure 49. Two 112-13 nuts. Lock nuts for securing jack handle to shaft. See figure 49.

Building the roll around cart We will start the construction with the portable cart. This is the heart of the machine. Begin by cutting the 4 pieces of 118" x 1-112" h.r.s. angle iron 24" long shown in figure 29. These are the top and bottom side rails for the cart.

The side and end rails fit together to form a top frame and a bottom frame for the cart as shown in figure 31. It is important to have both the top and bottom frames square, so check them with a framing square before welding. You can hold the rails in position with pipe clamps while you weld. Weld the 4 comers where shown in the figure.

Figure 29 Side railsfor the top and bonomframe of the ponable can. Make 4from 1/8"x 1-1/2" h.r.s. angle iron. I

Next cut the4 more pieces of 118" x 1-112" h.r.s. angle iron24" long shown in figure 30. Cut out the notches on each end. These are the top and bottom end rails for the can.

Figure 31 The figure above shows the construction of the top and bonomframe assembly for the roll around can. The figure at the right shows where to weld each comer.

i,,. ' 1

'';

,

i

The 4 legs shown in figure 32 are 32-112" long and cut from 118" x 1-112" h.r.s. angle iron. Weld or bolt them to the top and bottom shelf frame as shown in figure 33. C-clamps work well for holding the legs in position while welding.

Figure 30 End mils for fhe fop and bottomfrome of fhe ponable can. Make 4from 118" x 1-1/2" h.r.s. angle iron. Figure 32 Legs for fhe roll around can. Cur 4from 1/8"x 1-In" h.r.S. angle iron.

The top and bottom shelf are each cut from 14 gauge h.r.s. sheet metal. They are both identical in size, but the top shelf has several holes drilled in it while the bottom shelf does not. Since both shelves are identical in size I thought that the one drawing in figure 34 could represent both. Just don't drill any holes in the bottom shelf. I found that 14 gauge sheet steel was a little bit too much to cut with tin snips. I was able to do the cutting with a good quality jig saw and metal cutting saw blade. For the larger size holes in the top shelf I used a hole saw.

I

I

I

F

1:

OIAM.

3

q

23;

Figure 33 The legs are a c h e d to the corners of top and bonomframe as shown. Top edge of each leg is aligned with rhe top edge of the upper frame. The bottom edge of each leg is aligned with the bottom edge of the lower frame. The legs can be welded in position or bolted. Drawing in lower righr corner shows the finished assembly.

i

4

HOLES.

1 " DIAM.

,

\

,

I-;I

l4 1

14 HOLES.

DIAM.

I

Figure 34 Both the top and the bottom shelf are represented here. The top shelfis shown, but the bonom shelfis mcrly the same size only ir is without holes. Both are cw from a sheet of 14 gauge h.r.s..

Figure 36 Securing the top and bonom shelves to the canfmme.

Figure 35 Place the shelves in the conframe.

The finished shelves are placed in the can frame as shown above. Drill four 114" holes in the top and bottom shelf at the approximate locations shown in figure 36. Use these holes to secure the shelves to the frame using 114-20 x 112" bolts with nuts.

-

Next, install the casters on the cart. I used 2" metal casters on mine because they were cheap at the surplus store. Rubber casters would have been much bener. Two of the casters will need to be the

cart. Simply use the holes in your casters as templates to mark hole locations. Then drill the 114" holes and mount the casters with 1/4-20 bolts, nuts and lockwashers. See figure 38.

Align a mounting block at the outside edge of each comer and weld in place. See figure 40. This completes the cart portion of the project.

\

a 0

. I/,-2"

- -,". ".

BOLTS. NUTS b LOCK WASHERS

Make the 4 mounting blocks used for attaching the stationary posts. They are made from 114" h.r.s. flat bar. Dimensions are given in figure 39. Drill & tap a 1/4-20 hole where shown in each block, then thread a 1/4-20 x 314" bolt into each hole as shown..

-Y

1a4F1

AND

24

--2:

I

't:

-20

r

2 .. BOLT

L-

Figure 39 Mounting blocks. Make 4from 114" h.r.s. flat bar.

m u r e 40 Welding the mounting blocks in position.

35

Mounting the platen jack and control valves We discussed the platen jack at the beginning of the book. It is simply a trailer tongue jack that is modified for our purpose. It must be the rack and pinion type with the inside of the jack shaft Wig hollow. Normally these jacks are put together so that the gear rack is flush with the top end of the jack stand. A swivel wheel mounts on the bottom GEAR RACK end of the stand. The drawing in figure 41 JACK SHAFT shows what a jack normally looks l i e . For our purpose we ,,,,,,, will want to make a couple of modifications FOR WHEEL to thejack. F i t , remove the wheel from the jack 'k shaft. Next remove the jack shaft from the jack TRAILER JACK , '1 housing. This is done by simply cranking the '?\ handle. When the shaft i \ aq runs out of gear teeth it can be pulled from the housing. Once removed, ,i, hlrn the shaft end for end, then reinsert it in the jack and crank it back down. The lock pin hole FigUr~41 Normal mek &pinion sty& for the wheel should now ~mr~ler jack before ir has been beatthetopofthejack modified. shaft. See figure 42.

I+*,

b\\,

k

The other modification to the jack will be extending the length of the crank handle shaft. To do this you will need a 6" length of 1/2-13 tiu-eaded rod Pas shown in -43. File a flat spot on each side of one end oftherhreadedrodtofitthe jack handle. Next you will need a coupling nut prepared as jack had a coarser thread than the 1/2-13 cou~liina - - nut. To make the coupling nut fit over the existinn shaft. I drilled into one of the nut with a 112" drill bit, 518" deep. The other half of the coupling nut remains unchanged and will thread onto the shaft extension. Drill two 118" holes in each end of the couplii nut as shown. These holes, along with a couple of 118" pins will be used to hold the extension shaft assembly together. Figure 45 shows the assembly. The enlarged end of the coupling nut slips approximately 518" over the existing handle shaft. The other end of the coupling threads onto the exmsion shaft.

,,OLE FOR WHEEL

--GEAR RACK JACK SHAFT-,

i A

ead

Figure 42 h i & r jack @er first -paation. nle jack shq? lvrs been nuncdendfor end. Lockpin hole for trailer wheel is loaned a the top.

FLAT SPOTS FILED TO FIT HANDLE

Two, 314" threaded 2 STREET ELBOW ball valves can be A CI mounted on the top ., >..re,C,,, :STREET ELBOW of the can as BALL VALVE well. Two, 314" street 1 ', elbows are needed for LJ each valve. Apply Figure 46 Ball wlve assembly. 2 such thread tape or pipe assemblies are needed. com~oundto the male end bf the street elbows and screw one into each end of the ball valves. See figure 46. It does not matter whether the sheet elbows are black pipe or galvanized. Mount each ball valve assembly to the top shelf of the can with a 1-112" x 114-20 threaded U-bolt 2" long with nuts and lockwashers. See figure 47.

" ,,??y J'

-,34

'

\

DRILL 2 HOLES

A

Figure 44 Coupling nu!. One end is drilled with a 112" drill bit 518" deep ro fir existing handle shafr. The other end remains threaded 1/2-13, 518" deep.

Once assembled, use the 118" holes in each end of the coupling nut as a template for drilling the 118" holes through the handle shaft 1 / 2 - 1 3 COUPLING NUT and the extension shaft. Make pins from two 1" lengths of SHAFT EXTENSION , 118" round rod. Insen a pin into each 118" hole, through the coupling nut, the shaft and out the other Figure 45 mending the crank handle shaj?. end. The pin will be too loose in the hole. To make it fit tight you will need to swell it. With the pin still in the 118" hole, rest one end of it on a solid steel plate, then hit the other end with a hammer. This swells the pin making for a good tight fit. Rather than an 118" pin you could use #4 machine screws with nuts. Once the modifications have been made to the jack, mount it to the top of the table. You can use the holes in base of the jack as a template for marking the mounting hole locations on the top shelf. Drill mounting holes with a 114" drill bit, then bolt the jack in place using 114-20 x 314" bolts, nuts and lockwashers. See tigure 47.

:

I

USC THE HOLES IN THC BASE OF IHL JACK AS A TCUPLAlC TO LOCATC HOLES IN IOP SHCLF OF CART.

I:U-BOLTS 2 - LONG

Figure 47Momting thejackand wlve assemblies to the top sheyof the cart.

The extended DRILL 2 H O L E S ; length of the handle makes it necessary to 3 r add a support I ', bracket. Make the I8 I bracket from a piece ' of 10 gauge h.r.s. as ' ' I 34 shown in figure 48. 4; To mount the bracket, slide the Figure 48 Jack handle support bracket. 314" hole in the Madefrom logauge h.r.s. bracket onto the handle shaft until the bracket is flush with the side of the can. Center the 314" hole in the bracket around the handle shaft, then clamp it in position on the side of the cart. Using the mounting holes in the bracket as a template, mark and drill two 114" holes through the cart frame. Use these holes to fasten the bracket to the cart with 1/4-20 x 112" bolts, nuts and lockwashers. See figure 49.

:,

2\1

'

;--

:[A

1,

SUPPORT BRACKET

.. .&

JACK HANDLF

1- 2 0

x

BOLTS

WITH NUTS & LOCK WASHFRS

Figure 49 Mounting the handle and handle shaP suppon bracket.

Parts list for the adjustable platen assembly 4 pieces of 314" square x 11 gauge wall square tubing 20" long. These are the stationary posts for the platen table. See figure 50. 4 pieces of 114" x 314" x 314" c.r.s. flat bar. The bottom end caps for the stationary posts. See figure 51. 4 more pieces of 114" x 314" x 314" c.r.s. flat bar. The top end caps for the stationary posts. See figure 52. 4 pieces of 3/8-16 threaded rod 3 ' long. Studs for the stationary posts. See figure 54.

Eight 3\8-16 nuts. See figure 55. 2 pieces of 118" x 1-114" x 23" h.r.s. angle iron. Front and back rails for the platen table. See figure 57. 2 pieces of 118" x 1-114" x 23-318" h.r.s. angle iron. Side rails for the platen table. 4 pieces of 1" square x 11 gauge wall square tubing 8" long. Platen table legs. See figure 59. 1 piece of 114" x 2" x 23-114" h.r.s. flat bar. Platen table cross brace. See figure 65. 1 piece of 1-114" black pipe 2" long. Connecting link. See figure 66. One 2" hose clamp. To connect platen table to the jack shaft. See figure 69. 1 piece of 314" x 23" x 23-314" plywood or particle board. Platen table top. See figure 71. 1 Piece of formica slightly larger than the platen top above. See figure 72. 2 pieces of 314" x 1" x 21-114" pine board. Platen table risers. See figure 74. 2 pieces of 314" x 1" x 20-112" pine board. Platen table risers. See figure 74. A couple of dozen 1" wire brads and some wood glue to attach the risers to the platen top. See figure 75. 1 plumbing wall flange with 314" thread. See figure 76.

Four #I0 x 314" counter sink wood screws. For attaching the wall flange to the platen top. 1- 314" barb x 314" M.P.T. fitting. For attaching the vacuum line to the platen. See figure 76. 6' of 314" I.D. vacuum or hydraulic hose. Vacuum supply line to platen. See figure 77 & 78.

Building the adjustable platen 3

The adjustable platen includes the platen table and stationary posts that the table rides on. Make the 4 stationary posts from 314" square x 11 gauge steel wall square tubing. See figure 50. Make sure you cut the post ends off square because this will determine how straight they will stand after the endcaps have been welded on. Make 4 bottom end caps for the stationary posts as shown in figure 51. These are made from 114" x 314" flat bar and are cut 314" long. Drill and tap for 1/4-20 threads in the center of each

Make 4 more end caps for the other end of the stationary posts, except drill and tap these for 3/8-16 thread. See figure 52. Carefully tack weld the

q,

31 A

'

DRILL

a

TAP 2 - 1 6

+

<'IFL-2

,

1 1;4

end caps to each end Of the Figure 52 Top end caps for the post' say 4 from because if the welder is set too 3/4- c.r,s, bar. high it can easily bum through the thin wall of the square tubing. The end caps tapped i - 1 6 THREAOEO ROD \ 318-16 go on one end of each 3 \ stationary post while the end I, I l l l l ~ ~I ~; ~ ~r lb caps tapped 1/4-20 go on the 3 other end of each post. See figure 53. Figure 54 Stud for stalionary post. Make 4 from 3/8-16 threaded rod TOP E h D CAP TAPPED - I6

2

-6 'cb

II I

1

1,I

cut four pieces of 3/8-16 threaded rod 3" long. See figure 54. Screw a threaded rod into the 318-16 threaded hole in the top of each stationary post. Then thread two 318-16 nuts onto each. See figure 55. 2-16

NUTS-

2-16

STUD

L & TAP 1 / 4 - 2 0

Figure 50 Smiomry posrs for the platen table. Mak 4 p o & 314" square x 11 gauge wall square nrhinn

1

,

1 :4

Figure 51 Bonom end caps for the stationary posts. Make 4 from

BOTTOM END C A P TAPPED 1 - 2 0 -

,I'

-2

-0

POST

-%

Figure 53 Weld rop & bottom end caps to srationary post.

Figure 55 3/8-16 stud to errend out the top of the posr 2-1/4".

II

' 1

angle iron 23-318" long. Notch both ends of these rails back 1",then another little 118" notch on the 2 corners as shown.

1

SCREW A STATIONARY POST TO EACH CORNER.

Figure 58 Side mils for rhephen rable. Make 2from 1/8"x 1-1/4"h.r.s.

angle iron. Figure 56 Mowtr rhe srotionaty posts to the cat?.

Screw a stationary post onto the mounting blocks located on the comers of the roll around cart. See figure 56. The platen table is constructed next. Begin by cutting the front and back rails for the table as shown in figure 57 from 118" x 1-114" h.r.s. angle iron 23" long. Notch both ends back 1-118" as shown. Make the side rails shown in figure 58 from 118" x 1-114" h.r.s.

Figure 59 Platen rable legs. Make 4 from 1 " square x 11 gauge wall square rubing. Figure 57 Fronr and back rails for rhe plaren rable. Make 2 from

1/8"x 1-1/4 h.r.s. angle iron.

Cut four, 8" lengths of 1" square x 1 1 gauge wall steel square tubing for the platen table legs. See figure 59. In operation, as the platen table moves up and down it is riding on the stationary posts. For this reason, the platen table must be constructed to fit nicely over the posts. One way to accomplish this is to weld the table together while it is in position on the cart. Figure 60 shows the assembly. Figures 61-64 show how to go about assembling it. Before welding on the can it's a good idea to cover the shut off valves with a piece of scrap metal to protect them from weld splatter.

Begin by sliding a leg over each stationary post on the cart. See figure 61. The legs will fit loosely on each post. Expect about a 1116" movement from side to side in all directions. Insert temporary shims to center the legs on the posts. See figure 62. Place the front rail in position aligning the top edge of the rail with the top edge of each of the 2 front legs. Align the ends of the rail with the outside edges of the front legs. Use C-clamps to hold the rail in position. Weld where shown in figure 63. Weld the other 3 rails to the legs in the same

@wre 60 Platen table, See rexr for assembly instructions. PLATEN TABLE LEGS

J! Figure 61 Thefirst step in assembling the platen table is to sli& the table legs onto the stationary posts.

STATIONARY

\

Figure 63

SHIM TO CENTER p L A ~ l~A N e LL~~ ~

POST

ON

TAELE LEG,

Figun 62

4 I

-

WELD

, ,

1

Figure 65 Platen fable cross brace. Make 1from 1/4"x 2" h.r.s. flat bar. figure 64 View of the underside of the platen table. Weld each leg where shown by the arrows.

Figure 66 Connecting link to the jock shaft. Make I from 1-114" black pipe.

Position the 2" length of black pipe on the cross brace as shown in figure 67. Align the inside diameter of the pipe with the hole in the cross brace. When in position, weld the pipe to the cross brace.

manner. It's a good idea to label the rails as you weld them on. This makes for a handy reference when reinstalling the table later. I labeled mine, front, left side, rear, and right side. When done, remove the table from the machine by lifting it straight up until it slides off the stationary posts. Turn the table over and place it on a flat surface that is suitable for welding then proceed to weld the inside comers where shown. Make the platen cross brace from a 23-114" length of 114" x 2" h.r.s. flat bar. See figure 65. Drill a 1-114" hole in the center of the cross brace. One of the best methods to drill the hole is with a good quality 1-114" hole saw mounted in the drill press turning at about 200 rpm. The finished hole will be a tad bit larger than 1-114" diam., but that's OK. Cut a 2" long piece of 1-114" black gas pipe. See figure 66. This piece will be welded to the bottom side of the platen table cross brace and be used to connect the platen to the jack shaft.

1-1/1" RLACK PIPC

- .-

PLATEN TABLE CROSS BRACE

OUTSIDF JDINT.

Figure 67

/

P-., .,

Center the completed cross brace in the table frame and weld it in position. The brace center line is positioned along the center line running from the front rail to the back rail as shown in figure 68 .

Figure 68 Welding the cross brace in position. Center the cross brace in the table frame as shown and weld in position. Figure 70 This is how rhe mchine h k s so far.

Reinstall the completed platen table. Check your labeling to be sure the front rail is facing the front of the machine. The piece of 1-114" diam. pipe on the bottom of the platen table should align perfectly with the jack shaft. Then all that is needed to connect the platen table to the jack is a 2" hose clamp. See figure 69. To install the clamp, simply raise the table a bit and slide the 2" hose clamp over the jack shaft. Drop the table back down. Center the clamp around the joint and tighten it.

The top surface of the platen table can be constructed of 314" plywood or panicle board 23" wide x 23-314" long. See figure 71. Then the top is surfaced with a smooth heat resistant type material. The smooth level surface is necessary for forming a leak proof seal between the mold and the platen surface. Formica would make a good surface because it is able to withstand the heat used to soften the plastic and no screws are required to attach it. After doing some checking though, I found that formica is quite expensive and generally you must purchase a much larger quantity than what you need. To make the job cheaper and easier. hy searching for an old counter top with fonnica already on it and then cut it down to size. When new counter tops are installed there are often shon pieces left over and people throw this kind of stuff away or sell it at garage sales etc. So do some looking around before you buy a large sheet of formica. Smooth fiberglass panels also work. I found a small piece at ajunk yard for $1.00. It was about 1116" thickand smooth on both sides. I simply cut it to size and glued it on with contact cement.

Figure 72 shows attaching a sheet of formica slightly larger than the top using contact cement. Follow the instructions on the cement can for this procedure. After the cement sets, use a file to trim the formica back flush with the top edge.

.

FORMICA SHEET CUT SLIGHTLY LARGER THAN TABLL TOP.

I'

.'

TABLE TOP

Figure 72 Laying a sheet of fonnica on the surfoce of

the pla~entop

@re

71 Platen toblc top. Madefrom 3/4'plywood or panicle hoard.

Next, notch the corners of the top as shown in figure 73. A jig saw works good for this. The 1-114" hole in the center of the top shown in figure 73 is to allow the vacuum to reach the mold. A holesaw seemed to work best for drilling this hole.

Figure 75 Anach the risers to the under side of the top with I " wire brads and glue.

Figure 73 Notch each corner of the table top as shown and drill a 1-1/4" hole through the center.

Make risers for the table top from 314" x 1" boards as shown in figure 74. Attach the risers to the underside of the top with wire brads and glue as shown in figure 75.

Attach a 314" f.p.t. wall flange to the underside of the table with #10 x 314" wood screws as shown in figure 76. Center the inside diameter of the threaded portion of the flange with the 1-114" hole in the center of the platen. A good seal is required between the flange and the table so apply silicon sealant on the flat surface of the flange before attaching it. Wall flanges of the type shown are commonly available in black or galvanized iron. They can be found in the plumbing department of hardware stores and are most otien used for moveable and quick disconnect appliances. Screw a 314" barb x 314" m.p.t. fitting into the flange. ATTACH THE FLANGE WITH #10 X 3 / 4 " WOOD SCREWS,

,3/4"

BARB X 3/4"

M.P.T. FITTING

WALL 3/4"

LEFT & RIGHT SIDE RISERS MAKE I LEFT & I RIGHT

I

FRONT & REAR RISERS MAKE 1 FRONT & I REAR

Figure 74 The risers Figure 76 Attaching the wallflnnge to the underside of thephfen top.

55

Next you will need about 6' of 314" I.D. hose suitable for vacuum use. A normal pressure hose will not work because it's outer wall will not stand up to the outside pressure without collapsing. There were 2 options I came up with for this application. One was to use a hose specifically made to withstand high vacuum. This type hose has a very thick outer wall, but it is expensive. Grainger Industrial supply sells it. See sources section at the back of the book for more information about Grainger. The second option and the one I opted for is hydraulic hose. Hydraulic hose has a thick wire lined outer wall and is more than capable of withstanding the outside pressure without collapsing. Best of all, it is about 112 the cost of vacuum hose and more readily available too. You can purchase hydraulic hose at farm supply stores and auto parts stores. To install the vacuum hose, run it up through the center of jack shaft as shown in the photo in figure 77. Insert the hose up through the shaft and out the top of the platen table frame. Position the platen table on the table frame and push the end of the hose over the barbed fitting. See photo in figure 78. It

will take a little effort to push the hose onto the fitting and if the hose fits as tight as it should, there will be no need for a hose clamp. And that's a good thing because there's not enough room for one anyway. Next, lower the work table so that it rests flat on the frame. This completes the adjustable platen portion of the project.

Parts list for the clamp frame 2 pieces of 112" x 1" x 25" c.r.s or aluminum bar stock. Side rails for the clamp frame. See figure 80. Figure 77 Rrrrrrrirr!: f h ~~~ r ~ ~ ~ ~lrose rrrrrr rip rhrori@ flre jock dfafr.

2 pieces of 518" diameter x 22-112" long c.r.s. round rod. Slide rails for the clamp frame. See figure 81. 2 pieces of 112" x 1" x 26-112 c.r.s. or aluminum bar stock. Lower clamp side rails. See figure 82.

Figfire 78 Corrrrecfirrg rhe vocrrunl hose ro rlle barbed finirrg on rlte utlderside of rlre plnren table.

Figure 78A Plcrretr irr pusifiotr hose armclred. u,irlr ~~acuiim

2 pieces of 112" x 1" x 25-112" c.r.s. or aluminum bar stock. Upper clamp side rails. See figure 83. 2 pieces of 112" x 1" x 12" c.r.s. or aluminum bar stock. Clamp spreaders. See figure 84. 2 pieces of 112" x 1" x 3-114" c.r.s. or aluminum bar stock. Hinges for the upper clamp side rails. See figure 85. Four 3/8-16 nuts. To secure clamp frame assembly to stationary rails. See figure 88. 2 pieces of 112" x 1" x 20" c.r.s. or aluminum bar stock. Center clamp frame side rails. See figure 89A 2 pieces of 112" x 1" x 12" c.r.s. or aluminum bar stock. Spreaders for the center clamp frame. See figure 89B. 4 pieces of 118" x 1" x 3-314" strap iron. Clamp lock hinge. See figure 91. 2 pieces of 112" x 1" x 6" c.r.s. or aluminum bar stock. Clamp lock. See figure 92. 1 piece of 112" diameter x 21" long c.r.s. round rod. Clamp handle. See figure 93. Four #8 x 1" machine screws with nuts. For assembling the clamp lock. See figure 94.

Building the clamp frame The purpose of theclamp frame is to firmly hold the plastic sheets during the heating and vacuum process. See figure 79. It's a simple device consisting of a bottom clamp frame, a center clamp frame and a hinged upper frame with a lock mechanism attached. When in use, the lock bars lock under the lower clamp frame to hold the plastic sheet firmly between the bottom clamp frame and the center clamp frame. Notice the screws with lock nuts on top of the upper frame. These can be adjusted for different thicknesses of plastic. The clamp frame can also be adjusted to fit different mold sizes. The clamp frame assembly is made almost entirely of 112" x 1" bar stock. I used cold roll steel because I had quite a bit on hand, but aluminum bar stock would have worked as well and might have been a bit cheaper. Make the sides for the clamp frame from a 25" length of 112" x 1" aluminum or C.R.S. bar stock. Drill the holes as shown in figure 80. Make 2. Make 1 front and 1 rear slide rail, each 22-112" long from 518' diameter c.r.s. round rod. Drill & tap both ends of each rail for 114-20 threads as shown in figure 81.

lL;

.,/~ORlLL

2 HOLES

~

2

'4

.

.,

*:

1 -~

ORlLL 2 HOLES

-

,I

I

2

I

~

~

~

-

/

'< ',/ .,<,' /

UPPER CLAMP FRAME

._.

, , , ,

,,.

,,'

,..'

CENTER CLAMP FRAME BOTTOM CLAMP FRAME

LOWER CLAMP FRAME

Figure 79 Clampframe lock mechanism

~

~

.

.

-

25

' 7Figure 80 Side fmmefor the clamp frame. Make 2 from 1/2"x I " c.r.s. or aluminum bar stock.

‘4;5/ -. /

DRILL 8 TAP BOTH ENDS 1/4-20. 1 / 2 " DEEP

1

DIAM.

- .+/; -I -

,

, 22;

\\

,,;5-

I I ~

l-j!

'4

:!I,

-5L 8

t2

,;,;

-- - - - -

~~p~

Figure 81 Front & rear slide rails for the clamp frame. Make I front & 1 rear from 5/8" diameter c.r.s. round rod.

-

i i

\>..,

Make the lower clamp side rails as a matched pair from 112" x 1" aluminum or c.r.s bar stock. Drill the holes in the rails as shown in figure 82. Make the uwer clam^ side rails as a matched pair from 112" x 1 " aluminum or c.r.s. ~ r i l and i tap holes as shown in figure 83.

..

,

r-:

---

-.

-.. .

-

-

-1 .-

I DRILL 2 HOLES 5 / 8 DIAM. DRILL 2 HOLES 1/4

DIAM.

-9.

-

~~

I

12

'-1

--(:)-.I7 - f 1 -

~.21;

You will also need to make a couple of frame spreaders from 112" x 1" aluminum or c.r.s bar stock. The length of the spreaders is determined by your mold size up to the 12" width capacity of the machine. We can start by making a 12" long set as shown in figure

84. After a while you will end up with a few sets of spreaders of

-

~- 25;

.-

~

-

-~

ORILL 6r TAP BOTH ENOS

1-

4 12

20.

2

OEEP

~-

Figure 84 CIomp spreaders. Length is detemnnrned by widfh @mold. Make 2from 1/2"x I" aluminum or c.r.s. bar stock.

from 112" x 1 " aluminum or c.r.s. bar stock.

-

6

--

. L ~-

,, I

c

DRILL & TAP 2 HOLES 1/4-20

--

--= -

~-25;

1

-.

19-

.

-"

.- .

-

,I

a,

DRILL 3/32

d I

l,fl 4L;

- .. ---~

-

varying lengths to accommodate DIAM. different mold sizes. Make the 2 hinges for the upper clamp side rails from 112" x 1" aluminum or c.r.s. See figure 85. Attach a hinge to the back inside of each upper clamp side rail. See figre 86. If You have 85 Hinges for the wper built your frame out of c.r.s simply $ide rail. ~d~ 2 frorn weld a hinge to the back end of 1/2-x ~ " d ~ n u m o r c . r . bar s. each rail. If you have made yours srock. out of aluminum you can bolt the hinee to the rail.

cm

Figure 83 Upper clamp side mils. Make 2 as a marched pair from 1/2" x I " aluminum or c.r.s. round

Figure 86 Anaching the hinges to the end of the Cside rails.

WELD OR BOLT HINGES TO THE SIDE RAILS.

c-

LOWER CLAMP SIDE RAIL /SHOWN IN FIG. 8 2

,2 HOLES DRILLED I / 4

SIDE FRAME SHOWN

-<< , .-~ YIZLZ: ~

UPPER CLAMP SIDE

~

-

- 2 4

I

Figure 89A

I

~~~

--

P

~

18 20 CENTER CLAMP FRAME SIDE RAIL MAKE 2 FROM 1 / 2 X I ALUMIMUM OR C.R.S BAR STOCK.

SPREADERS SHOWN DRILL k TAP BOTH ENDS 3 / 4 OEEP 1/4-20.

12 SIDE FRAME SHOWN I N FIG. 8 0 LOWER CLAMP SIDE RAIL--ALL SHOWN IN FIG. 8 2

1 / 4 - 280 BOLTS X 3 1 ARE 4

Figure 89B

-

SPREADER FOR CENTER CLAMP FRAME. MAKE 2 FROM I / ? X I ALUMINUM OR C.R.S. BAR STOCK

Figure 87 The clamp assembly

When all of the individual parts are made, assemble the frame. An exploded view of the assembly is shown in figure 87. The bolts used are 114-20 x 314". After it is assembled. mount the clamp frame assembly to the top of the stationary posts as shown in figure 88.

Figure 89C Center clampframe assembly

Next make the center clamp frame side rails and spreaders as shown in figure 89A,89B & 89C.Assemble the center clamp frame with 114-20 x 314" bolts. To install the center clamp frame, raise the hinged upper clamp frame on the machine. Then position the center clamp frame on the lower clamp frame so that the spreaders and rails on both frames are aligned. See figure 90.

i DRILL 2 HOLES

i6

Figure 91 The clamp lock hinge. Make 4from 1/8" x I " strap iron.

,

136DIAM.

pi--

~.-- -

;--r

-

6

Figure 92 Clamp lock. Make 2 from 1/2"x I " aluminum or c.r.s. bar stock

Figure 90 Positioning the center clamp-

Now make 4 clamp lock hinges from 118" x 1" h.r.s. strap iron.

See figure 91.

Figure 93 Clamp handle. Make 1from 1/2" diameter c.r.s. roundrod.

Make the clamp lock shown in figure 92 from 112" x 1" aluminum or c.r.s. bar stock. Make the clamp handle in figure93 from a 21" long piece of 112" diameter c.r.s. round rod.

Assemble the clamp lock mechanism as shown in figure 94 by first attaching one end of each hinge to the end of each side rail on the upper clamp frame with #8 x 1" machine screws & nuts. Then

attach the other end of each hinge to the clamp lock bars using #8 x 1" machine screws with nuts. Next insert the lock handle through the 112" diameter holes in the bottom end of the lock bars. HINGES

.

'i

#8 X 1 MACHINE WITH NUTS

;

\.'\

2 pieces of 4" x 21-114" b.r.s. sheet metal. End panels for the heater box. See figure 104. 1 piece of 22-314" x 22-314" h.r.s. sheet metal. Top panel for the heater box. See figure 106. About 3 dozen 118" x 114" pop rivets. For assembling the heater box. 1 piece of 112" black pipe 10" long. Heater box hinge. See figure 108.

Material list for the heater 1 piece of 118" x 1-112" x 40" h.r.s. angle iron. Heater post. See figure 95. 1 piece of 318" x 112" x 3" h.r.s. flat bar. Mounting plate for hinge pin. See figure 96. 1 piece of 518" diameter c.r.s. round rod 5" long. Hinge pin. See figure 97. 1 piece of 118" x 2" h.r.s. angle iron 1" long. Heater post mounting bracket. See figure 100. 2 pieces of4" x 22-314". 20 gauge h.r.s. sheet metal. Side panels for the heater box. See figure 103.

1 piece of 118" x 1-114" strap iron 44" long. The hinge frame. See figure 109. Eight 1/4-20 x 112 bolts with nuts. For mounting the hinge frame to the heater box. See figure 113. One 120 volt 1500 watt heating element. Chromalox #CH2885. 2 pieces of 518" diameter x 314" long c.r.s. round rod. Heating element spacers. See figure 114. Two #8-32 x 1 machine screws with nuts. For attaching heating element to heater box. See figure 115. Two # 8 x 112" machine screws with nuts. Also needed for attaching heating element to heater box. See figure 115. 1 piece of 118" x 1" x 35" strap iron. Heater box brace. See figure 117. One 1/4-20 x 1-112" bolt & nut and one 1/4-20 x 112 bolt & nut. 1 can of aluminum color heat resistant spray paint. For painting the heater box. Paint should be able to withstand temperatures up to 1000 degrees F.

Building the heater The heater is just a box made of 20 gauge h.r.s. sheet metal with a heating element mounted inside. It swivels from side to side on a hinge pin that is mounted on the frame of the machine. It is wired with an electrical plug making it easy to remove from the machine. Begin by making the heater post from a piece of 118" x 1-112" angle iron 40" long. Drill the holes and cut the slot in the post as shown in figure 95.

4

DRILL 2 HOLES 1/4 \

(DRILL 1/4*

DRILL 2 HOLES 1/6:

of the post is the slotted end. Position the top surface of the mounting plate flush with the top edge of the post, then weld it in position as shown in figure 99.

I

i

I:--2;J

C U T OR FILE SLOT

-2-

L

-

12

40

i-1,;

--

1

--

8

1

1

Figure 100 Hearer post mounting bracket. Make I from 118" x 2" angle iron.

Figure 95 The hearer post. Make I from 118"~ 1-1/2"angle iron.

3/8-16

NUT,

MOUNTING BRACKET

Now make the mounting plate from a piece of 318" thick h.r.s. measuring 2-1/2" wide x 3" long. Drill a 518" hole in the center as shown in figure 96. Next cut a 5" length of 518" diameter c.r.s. round rod for the hinge pin. See figure 97.

2 I L

'I(

I 5

-I

DIAM.

I

Figure 97 Hinge pin. Make I from 518" c.r.s. round rod. I

BRAZE OR WELD

1

, /

<

<\ , 2 \.a,, .. ::P

,

1:

.

,,, .:..: .,--.

m u ? 98 ,Welding the h~ngepin to the mounrimg glare

~DIAM.

1 $Eli 1 :."

8

. ,

L 7;

HINGE PIN

1t 2

..

,.

!

4

Figure 96

p[ate

for the hinge pin. Make I from a piece of 318" x-112" x 3" h.r.s. flat

Insert the hinge pin into the 518" diameter hole in the mounting plate so that it is flush with the back side. Then braze or weld as shown in figure 98. Position the completed hinge pin assembly at the top of the heater post flush against the inside angle. For reference, the top end

1/4-20 x 3/4 BOLTS k NUTS

Figure 99 Welding the hinge pin to the heaterpost.

L

Make the mounting bracket for the heater post from a 1" length of 118" x 2" angle iron. Drill the 2 holes in the bracket as shown in figure 100. Slip the bracket onto the 3\8-16 stud protruding from the top of the left rear post of the machine. Secure with a 3/8-16 nut as shown in figure 101.

.

-.I

i'

Figure 101 Anaching the heaterpost to theleft rear leg ofthe

1

Position the heater post on the left rear leg of the machine as shown in figure 101. Position the post so that the slotted hole at the top of the post is approximately centered with the 114" hole in the mounting bracket. When positioned, clamp the post to the leg of the machine with a couple of C-clamps. Then, using the 114" holes in the post as a template, drill 114" holes through the leg of the cart. Then bolt the heater post to the can leg with 1/4-20 x 314" bolts, nuts and lockwashers. The heater box is made from 20 gauge h.r.s. sheet metal. It is made in sections and then riveted together with 1/8" pop rivets. You probably do not have a sheet metal brake so an alternative method of making the bends is with a sheet metal tool. The photo in figure 102 shows what a sheet metal tool looks like. It's really Figure Sheet metal tool iust a oair of vise e- r .i ~ with s wide flat jaws. if you are careful and make the bends gradually you will end up with a professional looking bend.

Cut out the 2 side panels for the heater box from 20 gauge h.r.s. sheet metal. Bend the ends of each side 90 degrees. See figure 103.

. 2 HOLES. 3 / 4

I2

HOLES 3/16

DlAU

Figure 103 Sidepanelsfor the heater box. Make 2 from 20 gauge h.r.s sheer metal.

.. ' \

I

DlAM

+

Figure 104 End panels for the heater box. Make 1 with holes and one withour holes from 20 gauge h.r.s. sheer metal.

Make the 2 end panels for the heater box from 20 gauge h.r.s. sheet metal. One with holes and one without as shown in figure 104. Assemble the sides and ends of the heater box as shown in figure 105. Drill holes for the 118" x 114" pop rivets in the approximate locations shown. Don't rivet the seams within 1" of the bottom because that would interfere with the installation of the top. Cut out the top panel of the heater box from 20 gauge h.r.s. sheet metal. Details are given in figure 106. Bend the edges up at 90 degrees.

Attach the top of the heater box to the assembled side section of the hex using 118" x 114" rivets located and spaced in the approximate locations shown in figure 107.

and endpanels of the Gater box with 1/8"x 1N"pop rivet^ -.OJO

..

,

CUT OUT THE 4 CORNfRS

/

2 HOLES

i DRILLED 3/96

/ ;

#-

2. 0

L e

/ t

ATTACH THE TOP 10 THE SIDES WITH I/8" POP RIVETS

BEND THE ENDS UP 9 0 DEGREES AT DOTTED LINE

R@re 106 Top panel for heater box. Make 1from 20 gauge h.r.s. sheel metal

Figure 107 Anaching the hater box top to the sides with 1/8"x 1N"pop rivets.

Next, make the hinge :OD \ from a 10" length of 112" ,!( B D black pipe. The inside I 10 diameter of the 112" black pipe I had on hand measured approximately 518" which made for an Figure 108 The heater box hinge . Make l from a piece of 1/2" black ideal fit on the hinge pin. pipe. Make the hinge frame next from a44" lo& piece of 118" x 1-114" h.r.s. strap iron. Locate and drill the 114" holes as shown in figure 109. The two 314" holes shown in the drawing will be located and drilled later to match the holes in the heater box.

vise. Insert the 'U" section of the frame in the vise. Place the Before hinge in the "U". tightening the vise, align the bend lines that should be marked 20" from either end with the jaws of the vise. Tighten the vise to force the legs of the frame against the hinge. Bend the legs equally in opposing directions to a 90 Figure 11 1 Bending [he legs of the degree angle. The photo in frame to 90 degrees figure 111 should make things a bit clearer. Position the hinge in the hinge frame as shown in figure 112. Weld the 2 together by putting a couple of short welds at the back of the hinge where shown in the figure.

HINGE

1

Figure 109 The hinge frame. Make l from 1/8" x 1-1/4" strap iron.

The hinge frame will have to be bent to fit around the hinge and then to a 90 degree angle. Since the frame is of light steel strap this is an easy job. Put a center mark on the hinge frame. . Clamp the hinge ( 10" long i piece of pipe) in a vice. Align ! the center line On the hinge Figure I I0 Bc,rtling the hinge Ji.ame. frame with the approximate center of the pipe. Bend the frame around the pipe to a "U"shape. See photo in figure 110. The bottom of the "U" should conform to the outside diameter of the pipe. Next, remove the pipe from the

d

Figure I12 WeMng the hinge to the hingeframe

Next, mount the hinge frame to the heater box as shown in figure 113. Center the hinge frame on the side of the heater box. Clamp the frame in position. Use the 114" holes in the frame as a template for drilling 114" holes in the heater box. Then bolt the frame to the heater box with 114-20 x 112 bolts with nuts.

FASTEN THE HINGE FRAME TO THE HEATER BOX WITH 1/4-20 X I / 2 BOLTS W/NUlS

POSITION THE FRAME AGAINST THE HLATLR BOX AS SHOWN. WHEN CENTERED. CLAMP IT IN POSITION. USE THC 1/4" HOLES IN THC FRAME AS A TLMPLATE TO LOCATE THEN DRILL 1/4" HOlES IN THE HEATCR BOX.

box.

Use the 314" holes in the back side of the heater box as a template to locate the position for the holes in the hinge bracket, then drill the holes. Now we can install the heating element, but first we need to make 2 spacer blocks each made from 518" diameter round rod, 314" long. These can be made of steel or aluminum. A 3/16" hole is drilled through the center of each block. See figure 114.

DRILL THROUGH

'"\{ 1 - 34

51;

y. ~,

pigure114 Hearing ele-spacer.de 2from 518" steel or alumuminwn round rod.

As mentioned earlier, we are using a 1500 wan, 120 volt Chromalox #CH2885 element. These are tough to find at the local level so I purchased several extra elements and am offering them for sale as a service to readers who may want to use them. Ordering information for this element can be found at the back of the book. One of the nice things about this element is that the mounting brackets are supplied with it. Figure 114 shows the installation. Insert the connection leads of the element through the 314" holes located at the back side of the heater box. The front mounting bracket of the element should rest flat against the inside wall of the box. Make sure there is plenty of clearance through the 314" holes .., for the heating element because you don't want the bare leads of ' ,. ,-.,I the element to touch the box. If ,, ,,., . < ' this were to happen it would cause r.. ,' an electrical short. If necessary enlarge the 314" holes to give additional clearance. Mount the front bracket to the heater box using the existing holes in the bracket as a template to drill through the heater box. Attach the bracket to the box with a couple of #8-32 x 112 machine screws and nuts. To fasten the element bracket, insert the spacer blocks between the bracket and the heater box , then fasten with #8-32 x 1" machine screws & nuts. Place the heater box in position on the hinge pin as shown in figure 116. You will notice that the box has a tendency to sag at the right front corner. TO solve Figure 116 Mounting the hearer. this problem make the cross brace

-

, '

I______',,: ,

A:

'

,'

,LINESJ

I

*/i

I1

-!'

3:

DRILL 1 / 4 /

Figure 117The brace for the hearerbox. Make Ifrom 1 1 8 " 1"strap ~ iron.

shown in figure 117 from a piece of 118" x 1" strap iron. Drill the holes as shown. Clamp the brace in a vise aligning the bend line located 9-112" from the end with the jaws of vise. Grip the brace with an adjustable wrench and give it a 112 twist as shown in figure 118. Then clamp the brace in the vise at the other bend line located

'"

from the end and make an Figure 118 Plrtrr,!~a approximate 13 degree bend. See the h,.nce, figure 119 for side and top views of the brace. .,,

~

-

~ ~

~

-

~

~

~

I

-

~~

I/? r \ r . , ~ r in

i

I

p

~

TOP VlEW

SIDE VIEW

-

,,I? I

Figure 119 Top and side views of the heater box brace.

Mount the brace to the heater box as shown in figure 120. It will be necessary to drill a 114" hole through the side of the hinge near the top before you can mount the brace. Then attach the brace to the

~

hinge with a 1/4-20 x 1-112" bolt & nut. Lay the other end of the brace on the heater top. Take the sag out of the heater box by raising the right front comer until it is level, then mark the hole location in the top of the heater box, near the center of the slot. Drill through the top with a 114" drill bit then bolt the brace to the top with a 114-20 x 112 bolt & nut. The slotted hole makes it possible to make adjustments to level the heater. By loosening the bolt you can raise or lower the front comer. Retighten the bolt to secure the new position. The extra length of the brace that hangs over the edge of the heater box makes a nice handle for swinging the heater from side to side. It is possible that the heater box could hit the adjustment bolts on top of the clamp frame. If this happens, remove the heater box and insert a spacer on the hinge pin to raise the height of the box. The heater delivers radiant heat to the plastic sheet. Radiant heat works much better when it has a shiny surface to reflect off of. To improve performance, I painted the inside of my heater box with high temperature spray paint. Important! Use only high temperature paint! I used an Ace Brand, shiny aluminum color, Hi Temp paint. This type of paint is available under several other brand names. It was purchased at the local Ace hardware and it was rated for temperatures up to 1000degrees F. I painted the outside of the heater box with the same paint to protect the finish from rust. DRILL A 1 / 4 " HOLF THROUGH I H L HINGE THEN BOLT THC BRACE TO THF HINGE WlTH A l/b-ZO X 1 -1/2 BOLT & NUT

DRILL A 1 / 1 " HOLE THROUGH THE TOP THEN BOLT THE BRACE TO TllF TOP RlGllT FRONT CORNFR WlTH A 1 / 4 - 2 0 X I / ? BOLT & NUT.

BRACE

Figure to the heater box.

1

Wiring material list 1 piece of 6-112" x 10-112" 20 gauge h.r.s. sheet metal. Connection box. See figure 121. An 18" length of 112" flexible metal conduit. Two 24" lengths of 14 gauge high temperature appliance wire rated at 450 degrees Centigrade (852 degrees Fahrenheit). A 24" length of #14 copper ground wire. A 15 amp female electrical plug. A 318" "emt" connecter. 1 piece of 5" x 33-112" h.r.s. sheet metal. For the control panel. See figure 124. Surface mount vacuum gauge. These are available from different manufacturers. I used a Grainger #1X547. Three #6 x 112" machine screws with nuts. For mounting the vacuum gauge. 15 amp 120 volt infinite range switch. These are available from several manufacturers. I used a Robenshaw #5500-135. 15 amp 120 volt toggle switch. A common item available at most hardware stores. For controlling power to an electric vacuum pump if one is used. Two 120 volt, 113 watt red neon indicator lights. Common item available at hardware and electrical supply stores. Four 114-20 x 112" bolts with nuts. For mounting the control panel. See figure 127. One 2-118" x 4" metal receptacle box. Approximately 6' of 3 wire power cord with a 20 amp rating. Approximately 1' of #12 romex 3 wire with ground. One 20 amp receptacle. 6 yellow wire nuts. One 15 amp male plug. One 20 amp male plug. Approximately 5' of power cord with a 15 amp rating.

Wiring the machine & building the control panel If you are not familiar with standard wiring practice, don't attempt this part of the project yourself. Consult a professional electrician. Insure that all wiring conforms to your local code. In this project, the white wire is neutral, the black wire is the hot wire and the bare copper wire is ground. For safety reasons, it is very important that the entire machine be grounded. The machine operates on a 20 amp circuit and as a safety precaution, I suggest plugging the machine into a GFI outlet. GFI stands for Ground Fault Interrupter. This type of outlet is very sensitive to electrical shorts and will immediately shut the circuit down if one occurs. First we will run the male power plug to the heater box. The

Figure 121 The connection box. Make I from 20 gauge h.r.s. sheet metal. Bend the sides up at the domed lines toform box atright Then bend tabs out.

material to do this consists of a connection box which we will make, an 18" length of 112" flexible metal conduit, two, 24" lengths of 14 gauge high temperature appliance wire, a 24" length of #14 ground wire, a 15 amp male electrical plug and a 318" "emt" connecter. Flexible metal conduit is available at most hardware and building supply stores. The high temp wire can be purchased at most appliance parts dealers. Expect to pay $1.50 or more per foot for it. High temp wire is often used in electric clothes dryers and ranges so if you know of one that has been junked you might check it out. The high temp wire is stranded, nickel plated copper and will have a mica glass insulation. The wire I used is rated at 450 degrees centigrade (852 degrees Fahrenheit). Make the connection box first from 20 gauge h.r.s. sheet metal. The layout is shown in figure 121. Then, insert 2 lengths of 14 gauge high temp wire and the copper ground lead through the flexible conduit. Connect the wires on one end to a male plug. Tighten the plug clamp over the end of the conduit. Slide a 318" "emt" connecter onto the other end of the conduit, tighten the clamp on the connecter to secure it to the end. Insert the wire and connecter into the 314" hole ! , . located in the side of the connection box. Secure the connector to the box with the nut. Connect the black (hot) wire One Of the heating Figure 122 Heating element conelement terminals and the white n,ions, copper ground lead is (neutral) wire to the other connected to the mounting bolt at terminal. For a better connec- the right side of the connection box. tion. it is best to solder or crimp a fork terminal on the end of each wire. Bolt the connection box to the heater box using the existing bolts used to attach the hinge frame. Don't forget to ground the heater box by connecting the copper ground lead to one of the bolts used to attach the connection box.

Before drilling holes in the control panel Please note: All of the holes in the panel have been sized for the components I used. (See material list for specific pan numbers). Pans from different manufactures muy require different size holes and installation procedures so follow the manufacturers instructions.

J :'.I

UILC PLUG

L.-i

Figure 123 The completed hearer box.

The next thing to build is the control panel. The layout is shown in figure 124. Make the control panel from a 5" x 33-112" piece of 20 gauge h.r.s. sheet metal. Make the 90 degree bends at each dotted line. ~-

28

THC 2 DOTTED LINES ARE BEND LINES ( . : 2 " DIAM.;, DRILL; ,,_ / . ,' 1 .. /

~~~

~

~

~~~

.. .,

,C

Ti?

-

-

.\ ,, ,

i

3 HOLES DRILLCD

;

,

\.

1

'

1

3:

1

1

Figure 124 Control panel layout. Bend each end up 90 degrees at the dotted line to shape the panel.

Figure 125 The completed control panel. The 2" diameter hole is for the vacuum gauge and is best drilled with a holesaw. The 318" hole is for the infinite range switch. The 112" hole below the infinite range switch is for a pilot light. The other two 112" holes are for the onloff switch for the electric vacuum pump if one is used and a pilot light for the switch. After the holes have been drilled, install the components in the control panel. See figure 126. Use the mounting holes in the bezel of the vacuum gauge as a template to locate holes in the control panel. Mount the vacuum gauge with three #6 x 112 machine screws with nuts. Install the 15 amp, 120 volt infinite range switch following the instructions that come with the switch. The 15 amp 120 volt toggle switch following manufacturers instructions. And the 120 volt, 113watt red neon indicator lights. The lights I used just snapped in.

ON/OFF

SWITCH FOR

! ELECTRIC VACUUM PUMP. : (OPTIONAL)

SMALL HEAD' SCRCWS

,?.---

PALNUT

# 6 X 1/2 SCREWS WlTH NUTS

'

/

Mount the control panel to the front of the machine with 1\4-20 x 112 bolts & nuts as shown in figure 127. Mount a metal receptacle box to ELECTRICAL BOX the left leg of the cart in the MOUNTED TO RIGHT FRONT LEG OF CART approximate location as shown in figure 128A. The drawing in figure 128 shows the wiring for the electrical box. Figure 129 shows the wiring from the electrical box, to the control panel, to the heater box.

OVERLAY *'

OUT TO CONTROL P A N E L . 4 ' OF 612 R O M E X 3 W I R E

HEATING ELEMENT INDICATOR LIGHT

Figure 126 Installing the vacuum gauge, infinite range switch, on/off switchfor wcuum pump and indicator lights. See text for the part numbers ofthe individual items.

SCREWS

TO 120VOLTS

<-u,

Figure 128 Wiringfor the power owlet. Ourla box is mounted 10 the rightfron~leg of the InOchi~. of the &chine.

Plumbing Figure 130 shows one way of plumbing the machine. Here we are using an air venturi pump as the vacuum source, but plumbing has been sized larger for an electric vacuum pump if one is used. Pans are lettered in the drawing with an accompanying material list for descriptions. Parts can be found at any good hardware store. Lengths of pipe required will be determined during assembly. The vacuum storage tanks shown have a capacity of 11 gallons. They were originally air supply tanks converted by removing the inlet fitting. This left the 112" F.P.T. opening in each rank. The tanks you use will likely be different and of course determined by availability andlor storage requirements of your machine. This means that the tank inlet and location may be different, but overall plumbing will remain similar. Except for galvanized and brass fittings, and a couple of lengths of copper tubing all plumbing is done with 314" schedule 40 pvc. All pvc connections are glued with pvc cement. The ends of the copper tubing are flared so you will need a flare tool. Leaks are a vacuums worst enemy. Use extra care in assembly to prevent them by using thread sealant on all threaded connections and tightening those connections securely. Once all of the parts are glued together the leaks are hard to fix. The air supply valve, letter W in the drawing is mounted in a convenient location on the left front leg of the machine. Some of the brass fittings I used on my machine may be difficult to find. For example, "N" in the drawing is a 314" female flare on one end reducing to a 114" male flare on the other. It's not always easy to find. Another way to accomplish the same thing in this instance would be to use reducing bushings. After the plumbing is complete, you're ready to operate the machine. Refer to pages 7-15 for operating procedure and the next section will contain a bit more information on mold procedure.

K- Male coupling. 114" flare - 114" pipe. Need 1 L- Reducer bushing. 314" pipe -114"pipe. Need 1 M- Male coupling. 314" pipe - 112" flare. Need 1 N- Female coupling. 112" flare - 114" flare. Need 1. 0-Vacuum gauge. Refer to control panel pans list. P- Vacuum pump. Air venturi type pump purchased from Harbor Freight. Item #03952 Q-314" MPT - 314" barb fitting. If hydraulic hose is used use fittings specified for that purpose for a better fit. You will need 2. R- 314" I.D. vacuum hose. Need 6'. Suggest substituting hydraulic hose instead. S- Floor flange. 314" pipe size. Need 1. T- Air supply line. Length to be determined by need. U- Couplings as needed. V- Male coupling ends as needed. W- Shut off valve size to be determined by inlet hose size. X-Shut off valves on cart top. 2 are needed. See roll around cart material list. A- Vacuum storage tanks B- 112" x 1-112"nipple. Need 2 C- Reducing "T".314" x 314" x 112". Need 2 D- 314" street elbow. Need 1 E-314" MPT- 314" PVC. 5 are needed. F- 314" PVC, various lengths as needed. G- 314" PVC elbow. Need 4 H- 314" PVC "T". Need 1 1- 114" ID copper tubing. 2 pieces, cut to length as required. J- 114" flare nuts. Need 4.

Vacuum molds Vacuum fonning is one of the easiest and least expensive methods of forming plastic. This is mainly because the molds are simple and of one piece construction. There are only a few things that you should know before you start making your own vacuum molds. 1. Molds must be of a solid material able to withstand the force exerted on them by atmospheric pressure as well as the temporary heat of the plastic when it comes in contact with the mold. They can be constructed of many materials some of which include, wood, fiberglass, plaster, epoxy, cast aluminum, machinedaluminum, etc. 2. Your molds should be given slight sloping sides with no undercuts. This is so the pattern can easily be removed from the formed plastic when the job is complete. It's best to slightly round all outside and inside corners. On wooden molds, I use auto body putty to fillet inside corners and I also use it to NI imperfections in the mold. Then I saud the mold smooth and round outside corners with the sandpaper at the same time. 3. You will have to provide vacuum draw holes in all negative molds and this may be necessary in some positive molds as well. Draw holes are usually placed in those parts of the mold that require the deepest draw. The two types of molds that you need to become familiar with are posin've (male) molds and negdve (female) molds.

Positive molds are solid versions of an item to be produced. With a positive mold, plastic is pulled over the mold. An example of a positive mold is the box mold shown in figure 131. It is a solid version of a 3-112" x 5" box that we will form lam in the book. Ne&e ntolds are those with the pattern shape recessed in the mold. The face mask we used in the example at the front of the book is made using a negative mold. The box mold shown in figure 132 is another example. With a negative mold, plastic is pulled into the mold.

Fipv 132 ~~~d~ mold

wa~ l ~ - x 5 " p ~ t i c

WOOD BLOCKS CUT FROM 2 X 4 LUMBER THEN GLUED TO PlNE

,---. 3/4

X 6 X 8-

PlNE BOARD

Fipv 131 llris isa vetysimpleposrtivemoldforfornung a 3-1/2"x5"box. It'snodcfroma5"long Z"x4"pineboard.Tisidcs ofthemoldaresloped 3 degreesto make it easier to mnove themold from t h e f o ~ ~ l a s t ihe c. comers are rowded sligluly erceptfor those at the h e ofthe mold. The oval shape you see in the center ofthe mold is auto body puny that war used ofthe mold. tofill a low spot in the s-e

VACUUM DRAW HOLES

-~_

,-.; '

/'

,%

I

Figure 134 Cross section of negative box mold showing 3/32" wcuwn draw holes. 7heputposeof the vacuum relief space is to open a path for the wcuwn to reach the draw holes.

I

-.

I

BOX CAVITY

'1

\

.

-- .4.'

SPACE

,,,P I , &?@-\.>>..

0 -

.\- -

,,I'

/r

- ..

,.

9-

-

c-

1

9.p

..

13.:;. .

.. .

. .<

,

,

. ,,:+ ., ,./

.,_

sp

I

-. , Yv'; . .

.,.,..2,/ .,>,.;,' ;

1 6'

::-

What sets this machine apart from others I have seen is its ability

to form plastic using negative molds. I know such machines exist, but I have not come across construction plans for one yet. The only plans I have seen are for machines that form over positive molds. There are some real advantages to negative molds and they are often much better suited for many kinds of forming. Especially when duplicating items. As a general rule, there will be less wasted plastic when you use a negative mold. Negative molds require less vacuum to form and in the process achieve much better detail. And heavy gauge plastic is easier to form using a negative mold. The only problem I can see with negative molds is that they require a little more work to make, but the extra effort can be worthwhile. Even though the machine was designed to use negative molds, you can still use positive molds if you build the platen attachment shown in figure 138. When forming over positive molds you will be limited to a 3" mold height because anything higher will interfere with your ability to swing the heater over to one side.

'-

, ,

. . . . .,,

Construction details for the platen attachment for positive molds are given in figure 135. It will be used in conjunction with the existing solid platen. It's a simple thing to build and is sized to fit within the 12" x 15" clamp frame on the machine. It needs to be a little thicker than the 1" depth of the clamp frame. The ledge extending out 112" around the bottom edge has a special purpose. When the table is raised, the bottom edge of the clamp frame puts pressure on the ledge, forcing the rubber seal tight against the surface of the solid platen. This prevents excessive vacuum loss during the forming process.

A%'. /'

t

RUBBER SEAL

- - .;'-

DRILL 3/32" HOLES IllROUGH PLAIEN. SPACED I " APART ,

Figure 135 Construction of the platen attachment usedforfonning positive molds.

/

/,/'

. .

.

After the platen attachment . . . . 'd is assembled, layout and drill .:. -. . . . . . '.>..h / 3132" holes, 1" apart over its .->+/&/' -.-'. entire surface. The holes are for the purpose of evenly distrib,,ting vacuum over the entire Figure 136 Drill 3/32"holes through surface. See figure 136. The phten affachmenfspeed I " q . ,

-

'

'

",

\~*, Figure 137Door& ,vindow seal used to seal bottom edge of the olaten attachmen1 and it's also used for sealing the bottom edge of negative molds.

-

1-1/16" thickness of the table is gained by gluing a couple of sheets of plywood together. The top surface can be made of the same material you used to make the existing solid platen. After the 3/32" holes have been drilled put a couple coats of urethane on the bottom surface of the new platen. This will give a nice smooth surface for the adhesive back on the rubber seal to attach

to. The seal can simply be door and

I have had the best luck with is sold under the brand name, 'MD". It's Figure 138 ne completed called 'Sub-zero Premium Weather for strip, K-profile EPDM". It's a flexin,,. ,oosirve ible rubber seal that is self-adhesive and provides an air tight seal. See figure 137. A brief description of the process for forming a sheet of plastic using a positive mold . . . Figure 139 Center the plafen attachment you just madeon the vocuum machine, resting it on rop of the existing solid platen. Raise the table to insure the platen wiflfir inside the clamp frame.

Figure 140 Center the posrive box moldfromfigure I31 on the platen surface.

Figure I41 Clamp a sheet of plastic in theframe. Here l am using ABS plastic that is ,030 thick.

From here on, the procedure is the same as described when forming the face mask, pages 10-15 at the beginning of the book. Lower the platen slightly so you see when the plastic sheet begins to sag. Swing the heater in position and begin heating the plastic to forming temperature. As I watched the ABS sheet begin to heat up, I noticed its surface bow up a bit and then become wavy. As it warmed further it sank back down and pulled tight in the frame for a minute or two then sag a bit in the frame. When I touched a screwdriver to the surface of the plastic it had rubbery feel and the screw driver left an indention in the plastic which quickly disappeared. At this point the plastic was ready to form. I quickly raised the platen table until it

was tight against the bottom of the clamp frame. Then, I opened the vacuum valve to form the box. I turned the heater off and swung it over to one side and continued to hold the vacuum on for a couple of seconds while the plastic cooled. Finally I

"

'

.

. "

...................... . . . , .., $4

Figure 144 Plastic is held sec~irelyin clamp frome. We are using .030 black ABS plastic. Next step is to swing the heater in position and begin the forming process.

removed the plastic Figure142Fomed3-1/2".r5"boxusinga from the frame and the pos;t;ve mold from the newly formed plastic box. If the mold is tough to remove, you can carefully pry it free using a screwdriver. The finished product before trimming looks like figure 142. When trimming light gauge plastic, a pair of tin snips or scissors does a good job. For heavier gauge plastic 118" and thicker you will have to use a jig saw or bandsaw to do your cutting and trimming. Rough edges can be smoothed with sandpaper. You can also trim plastic with the sharp blade of an exacto or utility knife. Don't cut through the plastic with the knife though. Simply score the surface, then bend the plastic sheet along the scored line and pieces should easily snap apart. We can form the same box with the negative mold in figure 132. The platen attachment will not be needed for this process so remove it from the machine. In the prior application we utilized the full

r m k

Figure 143 The negative mold inside the clampframe and resting on the platen. The center clamp frame is laying on theplaten table to one side. 6" spreaders are usedand they are spaced 8 " apan. As you can see, the 6" x 8" mold firs nicely inside the clampframe.

.-9

4 6P \

h<.'‘ 98

.!

---

Figure 145 Formed 3-1/2" x 5" plastic box using a negative mold.

A

capacity of the machine using the 12" frame spreaders spaced 15" apart. This mold only measures 6" x 8" so we will use 6" spreaders for the lower clamp side rails and the clamp frame. The spreaders are mounted in the frame in the same manner as the 12" spreaders except they are spaced 8" apart instead of 15" apart. Figure 143 shows the negative box mold in position on the platen. Figure 144 shows the sheet ready to be formed and figure 145 shows the finished product before trimming. The next example will demonstrate making and using molding plaster of paris molds for vacuum forming. For this type of work the product must be labeled molding plaster ofparis. Other types of plaster such as is used for patching walls will not work. You can find molding plaster of paris at most hobby stores.

Figure 152 n t r 11toldrtrntrd Owr lo rrvrfll ihr pflurnt.

Fi.$tirc 148 Cc.rrrc,r rltr pctrrcvn orr N ~ ~ t o l l i Ifoctrd. ~ t ! : A pirrr of am paper plorrd h e r ~ ~ r rrlte rt pnrrent o ~ t drlte tnoldirtg board ~ v i prnrrnr ll :Ire moldin.$plmer from sfirking to rhr hwrd.

Figure 149 77te ~ t d e mold n frame in posirion on rlre molding board. Partem i.r cerrrered in rltejkme.

--

kigtirc 150 Pc,t,r molrlirt,q pl(rsrcr of pork irtro rlte mold. Torrtp rlte plosrer do~vnforcirr~ nte it rig111agoirt.vf r l t e p ~ ~ e.m g m l is ro fill all voids orrd prrvenr air bribbles from slto~virtgup in me mold caviy

.

Figure 151 C u ~ ~ t p l r r r l ~rhr fill ntold ~~irhplavrrrorrd .vrrikc off l~l~rl.

Figrim 153 n t r p r r r r n ltos hcert rrtrro~ed front the mold.

In this project we are making a mold of the bowl shown in figure 146. We will use the mold to vacuum fonn a replica out of plastic. The overall size of this particular mold will be 8" x 9". To accommodate the mold on the machine. I used 9" spreaders spaced 8" apan. The entire process of making the mold. then forming a plastic bowl using the mold is shown in figures 146-157. A good release agent to prevent the plaster from sticking to the bowl is petroleum jelly. See figure 147. The molding board in figure 148 is a square piece of 314" plywood. The wooden mold frame shown in figure 149 is a rectangular wooden box with an ouuide measurement of 8" x 9". The box is made from 1" x 4" pine lumber and assembled with nails & glue. In figure 150 1 am pouring a batch of molding plaster of paris into the mold. This stuff drys really quick so you will have to work fast. Tamp the plaster with a stick or wooden dowel to force out air bubbles and fill all voids. After the plaster sets. turn the mold over to expose the pattern and remove it from the mold. There may be a few air holes or other imperfections left in the surface of the mold cavity after you remove the pattern. Small holes won't matter, but it's best to fill anything that is much larger than 1116" in diameter, then sand the repairs smooth. Sharp corners have a tendency to break off so sand a radius around the top edge of he mold cavity. 1 drilled 8 equally spaced 1116" holes around he bottom of the mold cavity as shown in figure 154. These are vacuum draw holes and as you can see they are located at that point of the mold cavity that requires the deepest draw. Drilling holes in plaster will dull a

8 EOUALLY SPACED 1/16" HOLES THROUGH THE i BOTTOM OF T H E MOLD CAVITY

-,'

>

Figure 154 Drill 8 equally spaced IN6" holes around the bottom of the mold cavity. ntese are vacuum draw holes and m you can see are located ar that pan of the mold which requires the deepest draw.

''

standard drill bit in a hurry. You can make your own drill bit out of a stiff piece of wire. To prepare the wire, simply flatten one end with a hammer, then grind it off at a slight angle. Now glue a rubber seal around the bottom edge of the mold as shown in figure 155. We a r e ready to form a plastic bowl with the mold. Figure 156

Figure 155 Bottom of bowl mold with seal in place. You can seethe circle of vacuum holes that have been drilled into the mold cavity.

Figure 156 Bowl mold in position on platen table. There is a piece of ,060 clear PET-G plastic clamped in the frame and molding process is ready to begin.

,

I

Figure 157 The finished plastic bowl wirh excess plastic trimmed away.

shows the mold on the platen with a sheet of .060clear co-polyester plastic also known as PET-G. The procedure for forming the bowl is the same. Heat the plastic to forming temperature. Raise the platen forcing the mold tight against the plastic. Then open the vacuum valve and the part is formed. PET-G seemed to be a little easier to heat than ABS. But other factors were much the same. As it warmed up, its surface became wavy, then pulled tight, then started to sag. When I touched the surface with a screwdriver it left a small indention for a couple of seconds. It was at this point that I formed the plastic. The finished product with the waste trimmed away is shown in figure 157.

Final thoughts Congratulations. You are now ready to design &produce plastic items using your new vacuum machine. There is still lots to learn but your knowledge can now best be increased by actually doing. Every time I build a new mold and form a sheet of plastic I learn something knew. As I worked on this project I was amazed at how well negative molds performed as compared to positive molds. Negative molds required lower forming temperatures and less vacuum. More detail was achieved in the finished pan especially when using heavier gauge plastic and I was able to get by with using smaller sheets of plastic when forming negative molds. Don't get me wrong, positive molds have their place too, but it is nice to have a choice. We have covered only a couple of methods of making molds in this book to get you familiar with the process. There are many other methods and materials that can be used. From here on you are only limited by your imagination. Panerns and molds can be carved, turned on a wood lathe or blocks of wood can even be glued together to form a shape. You can make patterns and molds from cast or machined aluminum, epoxy. fiberglass and the list goes on. I have formed ABS plastic on the machine up to 3/16" thick and I am sure the machine would form 114" thick plastic as well. Keep in mind though, the thicker the plastic, the longer it will take to reach forming temperature.

Sources for the heating element

Books

If you wish to purchase your heating element through a Chromalox representative, call or write, Weigand Industrial Division, Emerson Electric Co., 641 Alpha Drive, Pittsburgh, PA 15238. Phone (412) 967-3800 Or, as a service to readers, I purchased a few extra and will make them available to those of you wanting to build the machine. Ordering and price information are as follows. Prices are in effect as of the publication date of this book, but they are subject to change. Call or write for current prices and shipping costs.

Good books available on the subject of plastics. These should be available through your book seller or: Lindsay Publications, P.O. Box 538, Bradley, IL, 60915-0538. Phone 815-935-5353 http:llwww.lindsaybks.com

David J. Gingery Publishing P.O. Box 318 Rogersville, MO 65742-031 8 Phone (4 17) 890-1965 E-mail: [email protected]

Heating element 1500 watt, 120 volt, Chromalox #CH2885 Price . . . . . . .$30.00 plus shipping Source for air venturi pump Harbor Freight Tools 3491 Mission oaks Blvd. P.O. Box 6010 Camarilla. CA 93011-6010

Phone 1-800-423-2567 http:llwww.harborfreight.com

Source for vacuum gauge & vacuum hose Grainger Industrial supply They have many stores nation wide. Check the yellow pages or go online at http:llwww.grainger.com to find a store near you.

The h o p Builders Molding & Casting Handbook. By: Thurston James ISBN 1-55870-128-1 This book has an entire section on vacuum forming plastics using positive molds. Also has plans for building a vacuum forming machine. Do It Yourself Vacuum Forming By: Douglas E. Walsh No ISBN available This is an excellent book for the beginner. Walsh does an excellent job of covering the subject of vacuum forming using positive molds. Chapters include Types of plastics, mold materials, heat sources, vacuum sources and tips and examples. He also describes methods for building a simple machine. The Secrets Of Building A Plastic Injection Molding Machine By: Vincent R. Gingery ISBN 1-878087-19-3 In this book you will learn the basic principle of injection molding and how to design and make your own molds. You also get step by step instructions on how to build a small inexpensive tabletop injection molding machine capable of molding up to a half ounce of plastic.

Sources for plastic If you don't have a source for plastic in your area you might contact the venders below. Regal Plastic supply 111 E. 10th Ave. North Kansas City, MO 64116-9827 Regal plastics handles all types of plastic. Call Regal plastics at 1-800-627-2102 for the location of a branch store near you. Industrial Arts Supply 5724 West 36th Street Minneapolis, MN 55416-2594 Phone 612-920-7393 A good source of supplies to the plastic hobby market. Catalog costs $2.00 and they seem to cater mostly to schools and universities. They stock sheet plastic for vacuum forming. They also sell vacuum forming machines, injection molding machines and a host of other items as well.

Sources for metal Below is a list of mail order companies that I know of that sell steel, brass, and aluminum in rounds, flats, squares and angle. Blue Ridge Machimy &Tools, Box 536, Humcane, WV 25526. Phone (304) 562-3538. Campbell Tools, 2100 Selma Rd., Springfield, OH 45505. Phone (937) 322-8562 Metal Buyers Mart, N15 W22218 Watertown Rd#3, Waukesha,

WI 53186. Phone 800-657-0721

I

Build a Pkstlc Vacuum Fotming Machine

Dlscova why vacuum fot'rmag Is conrldend om of the moat venratlle of the pLWc thamofonuhq procnrsea After covulng basic p k i c tdmologygy you will learn how to make your own molds and we them to quickly form flat sheets ofthamoplawc into i n a t e slups with lnaedible accuracy. You will be able to f a b r h t ~ds i p s , pkstlc containns. htlve~,modelcarandaitpkmbodieslad mordAftnbulldingandusingyoulownvat~.um forming nuchtne. you will be capable of designing your ownn u s t a p k e pmjectsl aced to build a krge pmfessbnal " p " f " - equalityvacwm ' "= ormlngma~earehae.Iramaap by-step how to den@ and bulLl your own fully sclt-

cou~macbJnecapabteofmoldlnl,thickabnt pkaic wlth negathn molds -a type of mold not &en used in other m a ~ e sBy . Wdtng the platen attachment you can expand the upab111ty of your mKhine to use positlW molds u well. Simple~iron~ctionanddeorrdesfgo

&thIsarcwudlngpro~eatobutld.Bestofall,you WIU save money. By invcauag a few dollars and a blt of labor, you'll end up with a machine, whlch if puthad. would tost far morel And when you atan Nningoutprod~~trtosenathfleamarlreckuaft shows, a d hobby shops. you11 more than recwa the s a d consanctioncost. Your rmchime will operate on a standard 20 amp

I

120 volt acult. md it features an adjustable work rumEetoholdap.arietyofmoldrlohsheetsl~r. Your ma&e W use III a dud vacuum source beim e i k an m WM pump or chttrlr vacuum ~ n your d p r o f e r s quality ~ forming macb~ne

3

konwhealrrmLiogiteuytomovcwhennotin we. The &me here. Use them, add some hagination and you will be amazedat what you'll be able to mauufac~cquickly urd inupenrlvely.