Basic Vacuum Forming and Vacuum Machine Building

[Big Al]

Vacuum Storage

Ok Next up is my recomendation for aircans or airtanks!
Aircans or airtanks are great because you pull a vacuum on a can and store the vacuum. Mine is a converted 25 gal air compresser tank on wheels. and because it was a compressor at one time, it also has a steel mounting plate that my gast fits on perfectly!



This is a 11 gal and is top of the line from W.W.Grainger.
This one is nice but spendy! comes with a air gauge you will have to change it out to a Vac Gauge.

[attachment=3]Portable-Air-Tank-3EUJ9_AS01.jpg[/attachment]

You can get more specs on the tank here. Grainger Air Tank


This one is alot cheaper from Harbor Freight. this one is also 11 gal but is only $ 34.95

[attachment=2]HF Tank.jpg[/attachment]

Here is the Link for this one Harbor Frieght Air Tank


Next is the vacuum gauge pretty simple.
this particular one is kinda flashy but cheap any vacuum gauge you can fit on your pump or plumb into your system works fine!

[attachment=1]Vacuum Gauge.jpg[/attachment]

I think the colors change as the vacuum increases and decreses. Very Cool!

[attachment=0]Vac Gauge Colors.jpg[/attachment]

Harbor Frieght Gauge


My sytem is a Shop vac first stage that starts the pull.

My second stage is a high vol vacuum dump from the storage tank to the platen....My machine is made to work with two guy's one guy controls the plastic and another controls the vacuum valves.

Next Up: More Must Have Books

[Huttman]

I began to build my own as well. It is a 2 X 3 with a GAST 1023 pump.


you can see the wip pics HERE. Im actually selling this to a fellow trooper because I have been doing most of my work with my rotocaster. But I have gained a lot of knowledge building it

[Big Al]

Looks Great! is that a ProtoForm?.....and that looks like the same pump I have!.....mine is 3/4 HP Gast...I don't have it here or I would tell you the model # ...Did you ever finish the table? and did you ever pull any parts with it?

Big Al

[Huttman]

yeah its a 3/4 HP its one of GAST top of the line. im not sure what you mean by photoform. I designed it myself I did a test pull once i finished the platen and it worked awesome. i built a double flange system. was going to plum a two phase.

[Big Al]

More Must Have Books



This book is a must own as well and the following pic is from this book. This book is great and also covers many other subjects like casting, molding, Plug makeing...etc.

[attachment=6]Prop Masters HB.jpg[/attachment]


This is Thurston James's Vacuform machine from "The Prop Builder's Molding and Casting Handbook"

[attachment=7]James Thurston.jpg[/attachment]
You will see that this machine isn't far off from what we want to make! and the companion book to this book is "BUILD YOUR OWN VACUUM FORMING MACHINE by James E. Egner II"


This is the plan to make the home version of this flop over machine. and let me say This is a GREAT! Machine and has been use in prop departments for years!

[attachment=8]Build Your Own Vacuum Form Machine.jpg[/attachment]

[attachment=5]DIY Machine 1.jpg[/attachment]
If your going to build one of these you will utilize a two stage vacuum system!


The real neat part of this build, is creating the oven and using Nichrome wire and little porcelain insulators because making the heat even is half the battle here and it works Great!


This is a Awsome Web Site and has a complete Photo Essay on building the machine in this book Complete with production pics showing the use of the machine to make Storm Trooper armor.!

TK560 Vac Table

Here are a few pics from that site of Storm Trooper Armor created with a Flop over machine.

[attachment=4]Storm Trooper 1.jpg[/attachment]

[attachment=3]Storm Trooper 2.jpg[/attachment]


This pic is a good example of pulling multiple parts with one sheet.

[attachment=2]Storm Trooper 3.jpg[/attachment]


Notice the webing between the parts we will talk about webing later and why this webing is acceptable.

[attachment=1]Storm Trooper 4.jpg[/attachment]


These are his Plugs

[attachment=0]Storm Trooper Plugs.jpg[/attachment]


Both Of these books are available from many sources such as Amazon and other common book sellers so they are pretty easy to find.
Amazon
Borders
Barnes and Noble


The Companion book can be purchased at these sites as well.
Good Reading and a Must Have for Cylon Builders or Props or Nerd Builders like me or of any kind!

Next Up: Machine Types!

[Big Al]

yeah its a 3/4 HP its one of GAST top of the line. im not sure what you mean by photoform. I designed it myself I did a test pull once i finished the platen and it worked awesome. i built a double flange system. was going to plum a two phase.

I'm not sure what the model number is on my gast but same here it's a 3/4 HP top of the line and when I looked it up years ago and did the reasearch I believe it was the $700.00 model.

I didn't get mine new I got it from a friend who had several of them and used them in his machine shop on a metal cnc machine.

Instead of clamping their blank to a standard work surface, they made giant vacuum tables to hold their blanks in place during the milling and used the Gast pumps to provide the vacuum.

My Gast has two ways to wire it Single Phase 120 for reidential use and Three Phase 277 volt for commercial Apps.

I only know this because I had to rewire it for single phase mode before I could use it!

The Proto Form is the machine prints you can purchase From Cast Craft and is very similar to your machine and features an overhead oven and a mechanical transport with a handle for even deliver of the plastic to the platen.

I love makeing machines for my hobbies and I'll bet you do too!

I have also made and used Wire Foam cutters for makig plugs and wing cores for my models. and maybe some day I will do a forum on that subject.

Big Al

[Cylon-Knight]

Wonderful info, Big Al! Keep going

P.S. Love the new avatar too.

[Big Al]

Machine Types


There are several Vacuum forming machine methods and the result vary fom machine to machine.
I will cover 3 of them here so we can all be on the same page.

Excluding the Vacuum Box, (Useing your Kitchen oven to heat the plastic then slam it over the box) there are 3 ways to build a machine.

1. "FLOP OVER or FLIP FLOP TYPE". (Center Hinged Frame that flops over from heater to platen) Very good machines but they do have draw backs!

[attachment=1]Biy Vacuum Form Flop Over.jpg[/attachment]

The most common (and easier to build) among hobby guy's, is the "FLOP OVER or FLIP FLOP" method.

This method works great but again has definite draw backs.

This is a Castcraft Hobby Vac. I have the plans for this one too but I never built it. My friend that I work with on these machine builds, has built this one and it works great! Unitil it doesn't! and that's what I will talk about here.

[attachment=0]hobplanphoto.jpg[/attachment]


The Flop type has been used for years and is a great machine! The dissadvantage of this machine is that the heater is under the plastic! and this can cause you all kinds of Felger Carb!

First if you overheat the plastic, and is sags to far it will melt into your heater!, ruining yor plastic!, gumming up your heater!...and the most dangerous is that it can catch on fire!

The second problem is when you flop over, you must flop at just the right speed and motion! If you flop to fast and hard, you risk the Balooning effect... Air gathers in your saggy plastic like swinging a grocery bag in the wind except that your plastic is hot and will stretch prematurely and begin to cool from the air and not pull properly over your plug.

Third, If you flop to slow, gravity will pull down lateraly on your plastic shifting the sag from the center of your plastic when you reach the 90 degree point with your frame. This is not pretty the plastic starts to slide to the hinge point wrinkling and piling the whole way! The plastic get's destroyed before it ever touches the plug!

The fourth problem is that the transport design is hingend between the heater and the platen so the geometry of movement is an arc, thus your heated plastic enters the pull at a 45 degree angle and can cause webbing and uneven pulling and cooling. This makes your part thick on one side and thin on the other depending on the gauge of plastic you use.

Even with all of these challenges, These are awsome machines and with a little practice and a willingness to waste some material learning how to do it, you can make some bitch'n parts!

Yes I said Bitch'n .......showing my age I guess

[Big Al]

Machine Types Continued

2. "PLUNGE TYPE". (Overhead Heater, and Plastic is Plunged down over plug and platen). These are Great! and this is the type I like best!

[attachment=2]Home made 2.jpg[/attachment]


The straight down method makes verry happy parts!

and what I found is that a single stage works good for pulling small or shallow parts but your machine is limited. Large parts, taller parts or Deeper parts are a challenge untill you decide it's time for a 2 stage sytem....

With a two stage, the shop vac starts the pull and the high vol. vac is dumped just as the plastic starts to form. It all happens is a split second but the secondary High Vol. is strong enough and has enough force to pull the plastic over your lager or deeper parts!.

Also highly detailed parts require the Higher Vol. Vac to pull the plastic into all of the nooks and crannies.

The only problem with this method again is with the speed you transport your plastic and the distance between the heater and the platen.


Because these machines are manual, it's up to you to make a smooth transition from the heater to the platen. but it's alot easier to plunge straight down rather than an arc. However if you move to slow, you will get premature cooling resulting in webbing.

Moving to fast really isn't a problem here like in a flop over and the most important thing here is to be smooth but swift.

I mentioned the distance between the heater and the platen. Believe it or not even though the distance is only a foot to 3 feet depending on the size of your machine, that short distance can cause you a butt load of trouble! because the second the plastic leaves the heater it begins to cool. And the travlel time, (as fast as you can make it smoothly from top to bottom) still has an effect on your pull.

Just like before, Practice and wasted material is the only way you can reach near perfection.

The Proto Form Machine has a mechanical transport with an external handle and makes it almost flawless!

[attachment=1]proplanphoto.jpg[/attachment]


3. "ELEVATOR TYPE" (Plastic is stationary while Plug, Platen and vacuum chamber are elevated to the plastic) I won't cover these in to much detail because you find these mostly in a large industrial setting and very large machines because of the automation mechanics involved. Actuators for the elevator, Sequence timing circuitry, Heat sensors, Micro switches, indicator lights, Computer controlled valves...etc....very cool machines! but way to complexed for what we need and I have not found any info on anyone building a simple mechanical version of this one.


The "Flop Over" and the "Plunge" type are the two types of machines for Home Brew Guy's like us and the only reason I included the "Elevator Type" in this disscusion is because the Elevator type is used in manufacturing and is the near perfect machine.

The process takes a different approach to the finished part
Here is an animation I found on the internet.

[attachment=0]fullvac.gif[/attachment]

The plastic is loaded in the machine either manualy or automated depending on the size of the machine.

Then the heat is applied.

Then the Platen and the Plug are "Elevated" to the plastic as the vacuum is engaged.

This method keeps the plastic stationary and at the same time allows the plastic to maintain the same heat as it is pulled around the plug.

Bringing the plug to the plastic eliminates alot of these problems I mentioned because the machine is pushing the plug into the plastic as the vacuum comes on, allowing pre-stretching of the plastic before the vac is engaged so webbing almost never occurs.

Pretty smart huh? There are several Different ways and combinations of movements that a machine can be designed to to do inorder to form the plastic and I will show more examples later. But for our topic we will stick to the more basic designs because the more complexed the process, the bigger and more expensive the machine is.

Some day I have promised myself I would design a manual version of this machine......Maybe some day

Next Up: Plastics

[Huttman]

Well I sold my vac table because I dont really need it now since im using a rotocaster. However I still have access to a vac table should I need some (which I will soon with my vader shins)

Here is a vid of my rotocaster
http://www.youtube.com/watch?v=S_2KxPKTz3w

(sorry, i wasnt trying to change the topic from vac tables to rotocasters)

100 cubits if you can guess who is on my shirt

[Big Al]

Huntsman : Well I sold my vac table because I dont really need it now since im using a rotocaster. However I still have access to a vac table should I need some (which I will soon with my vader shins

That is a Fraking Awsome machine! and I wish I had one!

Roto Casting is a whole subject by it self and I would love to learn more about it!

You should start a thread on the subject! I promiss I will be right there asking most of the questions!

and sorry I can't make out who is on your shirt!

Does your friend have Blue prints for this machine? and if so can we get copies?

Also Rotoforming is THE best way to make helmets, masks, solid props such as mock guns...etc...

Awsome!


Big Al

[Huttman]

i pretty much made the plans, and assisted with the build. I have been wondering how well a rotocasted cylon helmet would chrome

[Big Al]

i pretty much made the plans, and assisted with the build. I have been wondering how well a rotocasted cylon helmet would chrome

I'm not to sure because I have never had to chrome anything for my planes.

I have created chrome looking parts starting with clear plastic and using a high gloss metalic paint from the inside of the part. and it works pretty good but I would consider it stand off scale. Because up close you can tell it's plastic but from 3 feet away it looks chrome....Anyway that's another subject....LOL

Do you have plans drawn up for this machine? and if so how much would you charge me for a copy? that is if you would be willing to sell me a copy.....I dunno maybe you want to mass produce them or somthing....

Just a thought....I collect plans for machines like yours and anything I can get my hands on for Home brew machinery that relates to my hobbies.

I have Vacuum Chambers I have made for removing bubbles from silicone when making resin casting molds.

I have made mechanical Hot wire tables for cutting large wing cores for my planes from blu foam.

I did have a print for a DIY CNC cutter for balsa. and I was working on getting the plans for a cnc laser cutter for balsa then my last lap top craped out and I lost the plans...but I'm going to do the research again so I can build those machines as well.

That machine you have is a work of art!

While I was watching your video I was thinking how in motion it does look like a small version of the Giant machine they used in the Jody Foster movie Contact!

If you speed it up maybe you can open up a worm hole!...LOL

Big Al

[Big Al]

Plastics

548_acrylic_color.jpg (12.29 KiB) Viewed 5580 times

548_acrylic_color.jpg (12.29 KiB) Viewed 5580 times

There are over 6 million plus man made chemical compounds that are used in our modern world. from these, thousands of them are compounds that make up what we all know as plastic.

Plastics are made from polymers to petroleum and a plethora of ingredients in between. (and nothing rymes with Plethora)

From all of these compounds, there are only about 6 types of plastics that we use in hobby related builds. and I'm not saying that these are the only plastics you can use as the plastic companies create new compounds eveyday and there might be some new plastics that would be a perfect fit

However for the parts we are making, R/C aircraft, R/C car bodies, Cylon suits, Stormtrooper suits etc....these plastics seem to be the best for these applications and the Vacuum Forming process and are readily available.

Formable plastics are available from several sources starting at your local hobby shop. Most hobby shops are limited on what they carry mostly styrene and other light weight plastics for model railroad construction I.E. Minature buildings, Pre formed Textured panels such as simulated bricks, rocks , wood panels, planking and a small stock of blank sheets. Unfortunatly most of the sheeting is rather small and is not suitable for our application. Also Buying plastic in this small amount is most expensive.

I'm not sure if you have one in your town, but here in California we have Tap Plastics stores which is a good source for plastic stock and you can purchase them in larger sizes and in bulk. Tap Plastics is better than the hobby shop for selection but if you are going to buy large sheets, (Best Priceing) I would suggest you buy on line.

Here are some links to the plastic companies that I have delt with.

Tap Plastics

Interstate Plastics

K-Mac Plastics

Midland Plastics

Emco Plastics

All very good sources for plastic.


Ok here is the list of formable plastics we use.


ABS (Acryonitrile Butadien Styrene)

PVC Type 2 (Poly Vinyl Chloride)

Styrene (High Impact Type)

CAB (Cellulose Acetate Butyrate)

Polycarbonate

Pet-G (PolyEthleneTerephtalate Glycol)

All of these plastics are very good for Vacumm forming and all have different applications. From opaque to clear, they all have different properties such as density, Thickness, paintability, Tinsel strength, etc. depending on the part you are making.

My next posts will go into more detail about each plastic I mentioned here.

[Huttman]

ABS FTW