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charper
11-21-2006, 08:04 PM
What types of materials can you vacuum form?
Acrylic. anyone? any thickness?
PC?
PE?
Please explain

I am more artist than machinist..so please explain someone

drcrash
11-23-2006, 01:12 AM
Hobbyists often vacuum form acrylics (like Plexiglas), polystyrenes, polycarbonates (like Lexan), and PETG.

There are a lot of other kinds of plastics that can be vacuum formed, such as polypropylene and PVC.

Most of these things are fairly easy to vacuum form on a fairly simple home machine in thicknesses up to about 1/8". With a reasonably well-designed oven and a decent vacuum source, it's common to vacuum form plastics 1/4" on homebrew hobbyist machines.

Some people (including me) vacuum form foams. I've been playing around with vacuum forming EVA foam, which is a rubbery plastic foam (sold as "craft foam" in small sheets in craft stores). Some people (not me, yet) vacuum form extruded polystyrene (rigid) foams.

http://i136.photobucket.com/albums/q176/drcrashpix/miscmasks/halloween06blackmask.jpg

The mask on the left is 6mm EVA foam; the one on the right is 2 mm (I think). The one on the left didn't pull down very tightly, using only a shop vac; a high vacuum system does much better. (Although the thick foam still tends to smooth things considerably).

This one is acrylic---a piece of textured fluorescent light diffuser (over the white plaster buck it was formed on):

http://i136.photobucket.com/albums/q176/drcrashpix/miscmasks/crackedicecropped.jpg

(The green cast is an artifact of fluorescent lighting, but I like it.)

Here's the same one over the black foam one, in better lighting:

http://i136.photobucket.com/albums/q176/drcrashpix/miscmasks/blackice2.jpg

charper
11-23-2006, 10:17 PM
your foams are amazing!!!!!!!!! Great art applications. PM me. Tell me more. Very Very creative. How do I get started! SIgn me up!

drcrash
11-24-2006, 10:50 PM
your foams are amazing!!!!!!!!! Great art applications. PM me. Tell me more. Very Very creative. How do I get started! SIgn me up!

It's not hard. Go down to your local craft store and get some craft foam. Bake it at around 325 for around 2 minutes. (One-sided IR heating works for 2 or 3 mm foam. I'm still experimenting with 6 mm foam.) If it starts to smoke, or disintegrates, or comes out weirdly papery, you're overcooking it and should back off a bit on either the temp or the time or both. Don't expect it to sag like styrene or acrylic... it just doesn't. (It rumples a little, the tightens up, within the first 30 seconds to a minute. You keep baking it for a while after that.)

Once you figure out the heat and time settings for your oven, it vacuum forms beautifully.

Here's what happens when you cook it a little too hot for a little too long:

http://i136.photobucket.com/albums/q176/drcrashpix/miscmasks/overcookedEVA.jpg

Do experiment with it. (One of the nice things about craft foam is that it's cheap in small quantities. My local dollar store sells a package of 6 9" x 12" sheets for a dollar, so an experiment only costs 16 cents.) If you cook it longer and slower, it comes out differently (less foamy, darker, and more leatherlike). Pretty cool.

As for the textured acrylic (and styrene), just go down to your local hardware store(s) and check out the selection of 2 ft. x 4 ft. fluorescent diffuser ceiling panels. Styrene ones are about $5 and acrylic are $7 or so. You can make several masks from one panel. (You can get 6 12" x 16" pieces out of one 2 x 4 ft. ceiling panel, or 10 9" x 12".)

If you get bubbles in your acrylic, either you're heating it too fast or it's absorbed water from the atmosphere and needs to be dried. (Acrylic does that when it's humid.) To dry it, you can wait until it's less humid, or bake it on a very low oven setting for an hour or so, or make a "hot box" out of plywood, with a lightbulb to keep it warm, and leave it overnight in the box. (I can scrape up a link to instructions if you're interested.)

It's interesting to form the textured panels textured side up and textured side down. Doing it textured side down gives you muted textures, but they're kinda nice in their own way.

The "white mist" styrene from home depot has a texture pretty similar to metal cast in sand. Texture-side down gives you something locally smoother with more subtle irregularities.

An airbrush artist friend and I are going to be experimenting with what happens when you airbrush these textures in different ways, both from the front and from the back.

charper
11-26-2006, 03:41 AM
It's not hard. Go down to your local craft store and get some craft foam. Bake it at around 325 for around 2 minutes.

1. My vacuum former does not have a temperature control, so how I do work with materials other than the supplied?
2. By craft foam, or you talking about those colored "foamy" sheets you use with the kids that I have have plenty of if I have a 6 year old?
3. What kind of thickeness are you looking ot for the styrene diffuser fluroescent ceiling tiles. I have some at work, but they seem awfully thick!
4. What type of maaterial did you vacum form onto? Did you mold this material yourself?

Thank you, I didn't realize there were other materials to vacuum form other than the "Vacuum form material" sold outside of my supplier catalog

drcrash
11-27-2006, 07:16 AM
1. My vacuum former does not have a temperature control, so how I do work with materials other than the supplied?

The simple but tedious way to do it is to flip the switch on and off on a 20-second cycle. You might want to add a temperature control, like an "infinite switch" for a stove burner. (Which basically just switches the heat on and off cyclically to give about the right average heat.)

What kind of vacuum former do you have? If it's a small one, you may be able to use an infinite switch from a cheap one-burner countertop stove from the drug store. (Walgreens had them on sale for $7 last week.)


2. By craft foam, or you talking about those colored "foamy" sheets you use with the kids that I have have plenty of if I have a 6 year old?

That's the stuff, Ethylene Vinyl Acetate foam. Foamies (TM) is the best-known brand. Regular Foamies is 2 mm thick, Extra Thick Foamies is 3 mm, and Super Thick Foamies is 6 mm.


3. What kind of thickeness are you looking ot for the styrene diffuser fluroescent ceiling tiles. I have some at work, but they seem awfully thick!

The White Mist styrene seems to be about 1/16 inch or so. The Cracked Ice acrylic seems a little thicker on average.

Keep in mind that it ends up a little thinner after stretching it over the mold. I wish mine was a little thicker to start with; if yours are thicker, that may be a good thing.


4. What type of maaterial did you vacum form onto? Did you mold this material yourself?

Some kind of gypsum cement, I forget which. (Hydrocal? Ultracal? Hydrostone?) It's like plaster, but is harder when it sets. It's more expensive than Plaster of Paris in hobby or art stores, but if you find a cement supply place that carries it, it's pretty cheap.

I've also used "water putty" from the hardware store, which is a bit more expensive and a lot tougher than plaster of paris. (You can mix the two, and get most of the strength for pretty cheap.) I usually put drywall reinforcing tape (fiberglass mesh) in there, too.

The masks in the pictures I posted were made on life casts of my face and (mostly) my wife's face, which we did of each other. (Not at the same time.) Most of the ones in the pictures were done from a plaster cast of my wife; the one of me was done with an alginate cast with a plaster mother mold.

Slow-setting alginate is great stuff, but a little pricey. We use the blue stuff (I forget the name) from www.pinkhouse.com, and like it a lot.


Thank you, I didn't realize there were other materials to vacuum form other than the "Vacuum form material" sold outside of my supplier catalog

What supplier catalog is that? If you're buying in small quantities from a hobbyist or art supply place, you're likely paying way too much. You should find a local plastics supplier. A 4 x 8 foot sheet of thin high-impact styrene is less than $20, for example. If you want to make masks or other small things, you can cut that into 24 12" x 16" sheets, so they're less than a buck each.

There are two kinds of plastics suppliers---the ones that are happy to sell you a single sheet, and the ones that have a minimum order of $100 or so. It pays to call around and figure out which of your local suppliers are happy to sell single sheets. (They'll also generally sell you a part of a sheet, but may or may not make it unreasonably expensive with cutting fees; ask about that, too.)

Another source of small quantities of some plastics is sign-making places. They may sell you small quantities cheap. (Especially if you make it clear you're not making signs and competing with them.)

charper
11-28-2006, 02:43 AM
You might want to add a temperature control, like an "infinite switch" for a stove burner. (Which basically just switches the heat on and off cyclically to give about the right average heat.)



I want to radioshack it, any suggestions? Resources?

drcrash
11-28-2006, 07:00 AM
I want to radioshack it, any suggestions? Resources?

What kind of vacuum former do you have? In particular, how many watts does the heating element consume? (Or amps, if it tells you that; from that and the voltage you can figure out the watts.)

I'm guessing this is a fairly small machine (since you're interested in buildign a bigger one) in the 1000 to 1500 watt range...? I'm also guessing that it runs on regular 115 volt wall outlet current, not a 230 volt major appliance outlet...?

If it's really small, 1000 watts or less, you can use an infinite switch for an electric stove surface burner. (I was just at Walgreens and they still have 1000 watt 115 volt burners w/heat controls for $7 this week.)

If it's more than 1000 watts, but uses multiple heating elements, you could probably use two 1000-watt infinite switches. Depending on the type and arrangement of heating elements in your unit, that might let you control the center heat and the edges differently, which can be good for fine-tuning the heat distribution. The downside is that you have to figure out the correspnding settings for both knobs, and change them both when you want to change the overall heat. (Mark a good place for "low" and "high" on each knob, and put them both low, both high, or both in the middle.)

You may also find the right wattage (and voltage) of inifinite switch cheap on eBay as a replacement part for a stove or oven.

(You may also want to buy a thermometer for it. I've got one that cost about $7 from Lowe's---it's designed to be mounted on the side of a barbecue grill, with the probe sticking into a 1/4" hole in the grill housing.)

charper
11-28-2006, 10:41 AM
What kind of vacuum former do you have? In particular, how many watts does the heating element consume?

I am at school and just took pictures of my machine to hopefully post this evening. It is a small powerlab vacuum former 1012. I opened it up, I have the power requirements for the vacuum pump, but I can't tell where the heating element is. Sorry:confused:

The machine runs on a standard 100V outlet and has a small med of about 10" X 8"

charper
11-28-2006, 12:24 PM
What supplier catalog is that? If you're buying in small quantities from a hobbyist or art supply place, you're likely paying way too much. You should find a local plastics supplier. A 4 x 8 foot sheet of thin high-impact styrene is less than $20, for example.

I can get a 4' X 8' X .02" sheet of PS for $17 from IASCO-tesco.com, my industrial arts supplier

drcrash
11-28-2006, 01:16 PM
I can get a 4' X 8' X .02" sheet of PS for $17 from IASCO-tesco.com, my industrial arts supplier

Cool. (But what's the shipping? Might still be cheaper to buy locally.)

Neat catalog.

That little $555 roto-molder looks suspiciously like a rotisserie cooker you can find in a thrift shop for $5, with an extra bit in the middle.

I'll bet you could make one of those for next to nothing, if you thought about it. Hmmm... I wonder if somebody's got plans on the intarweb for that...

It would be very cool to have a rotomolder, even a little one.

charper
11-28-2006, 08:46 PM
I have no specs on my heating element...too old..

I do have a rotational molder and I can make little skulls out of aluminum mold that I purchased from Iasco-Tesco. With a 275 heat, I wonder what other type of mold besides aluminum I can use to roll around plastic material, heat, and release..

but back to the vacuum former. SHould I bother getting a heating controller for the old former, or work to build a new machine?

http://img165.imageshack.us/img165/7454/vacuumformer1vi0.jpg

drcrash
11-29-2006, 01:34 AM
I have no specs on my heating element...too old..

If you decide you want to tinker with it, you could probably open up the machine and find out. With a multimeter you could figure out the resistance and amperage.



I do have a rotational molder and I can make little skulls out of aluminum mold that I purchased from Iasco-Tesco. With a 275 heat, I wonder what other type of mold besides aluminum I can use to roll around plastic material, heat, and release..

I've been wondering that, too. I'm guessing the thermal conductivity of the aluminum is important, and that a silicone mold likely would not work. Parts of the plastic (where the mold is thin) would get hot much sooner than other parts, and would burn before other parts did anything much at all.

I was wondering today whether ZA-27 Zinc-Aluminum alloy would work. You can cook that up on a portable electric stove burner and cast it at home. Seems likely that it's conductive enough, but I don't really know.


but back to the vacuum former. SHould I bother getting a heating controller for the old former, or work to build a new machine?

I guess that would depend on what you want to do. If you want to make bigger stuff, you're going to need a bigger machine anyway. But you may want to enhance the little one, too.

drcrash
11-29-2006, 01:39 AM
I do have a rotational molder and I can make little skulls out of aluminum mold that I purchased from Iasco-Tesco. With a 275 heat, I wonder what other type of mold besides aluminum I can use to roll around plastic material, heat, and release..

I've heard of people using a rotomolder with the heat off to hollow mold thermoset resins (polyester? epoxy?). For that, a silicone mold should work fine. I've also seen plans somwhere for a shop project, building a no-heat roto-molder for that. (It's basically just a two-axis rotisserie thing, and most of the project was making the gears.) It wouldn't be hard to make one that could make considerably bigger parts than the little mini-rotomolder.

charper
11-29-2006, 03:49 AM
If you decide you want to tinker with it, you could probably open up the machine and find out. With a multimeter you could figure out the resistance and amperage..

I might just do this for giggles if I could figure out where the heating elements was. I see a timer, vacuum pump, light, switch for vacuum, and fuse box, but that is all without disecting.



I guess that would depend on what you want to do. If you want to make bigger stuff, you're going to need a bigger machine anyway. But you may want to enhance the little one, too.

OK. I think I want to build a bigger machine, so this will be my last post on this thread. My main reason being that the small vacuum former belongs to the school. I suppose I could alter it, but it has an inventory number, etc.

2nd, this may be my last year of teaching, so I need to build something (funded by me of course) that I can take with me, that I will have access to, so I am interested in compactability and I believe you said your machine can be easily disassembled and put away.

So....let me start a new thread on a portable vaccuum former if you vacuum people don't mind.

drcrash
11-29-2006, 10:51 AM
I might just do this for giggles if I could figure out where the heating elements was. I see a timer, vacuum pump, light, switch for vacuum, and fuse box, but that is all without disecting.

I'm assuming the heating element is in the flattish box on the top, and that you pull it forward over the plastic with the black handle on the front of it. That puts the heater over the plastic. (Assuming the plastic goes in the frame over the hole.) Then you push the heater back away from the plastic, and crank the buck up through the plastic. Does that sound about right?

If that's right, I think you can probably see the heater with a mirror down in the hole, on the platen, if you don't put a piece of plastic in the frame. Pull the heater box halfway forward, and look down in the mirror to see up into the heater box. I'm guessing you'll see either bare nichrome coils about 1/4" in diameter or calrod bars about 3/8" in diameter. (Which are just nichrome coils embedded in a ceramic rod, encased in a grounded metal jacket.)