Non-Toxic Styrofoam or Something that's as strong as Acrylic but cheaper

[cubbiesfan50]

I'm looking to create a new product that would be made out of styrofoam or like acrylic but cheaper, hold water, and hopefully would use a vacuum molding machine. I have a few questions about this: How expensive would it be to make a vacuum molding machine? Can I vacuum mold styrofoam? How can I make a 3-d figure with a vacuum mold? How expensive is styrofoam to buy in semi-thick sheets or the pellets? How can i get it so that the water is non-toxic? (I was thinking some kind of thin coating of wax, but I have no clue what kind) Any information that you could give to me about working with styrofoam would be greatly appreciated.

[awerby]

I'm looking to create a new product that would be made out of styrofoam or like acrylic but cheaper, hold water, and hopefully would use a vacuum molding machine. I have a few questions about this: How expensive would it be to make a vacuum molding machine?

[I suppose you could spend almost any amount of money, depending on the parts you started with, the size, and what you wanted it to do. Your skill level and shop equipment would figure into the equation as well.]

Can I vacuum mold styrofoam?

[No. Vacuum-forming (which is what I assume you're talking about) only works with thin thermoplastic sheets.]

How can I make a 3-d figure with a vacuum mold?

[Since a vacuum former only makes single-sided parts, you'd either have to make a figure in relief or piece together a figure in the round.]

How expensive is styrofoam to buy in semi-thick sheets or the pellets?

[It's not very expensive.]

How can i get it so that the water is non-toxic? (I was thinking some kind of thin coating of wax, but I have no clue what kind)

[What water? Styrofoam doesn't poison water on contact; that's why you can drink coffee out of styrofoam cups.]

Any information that you could give to me about working with styrofoam would be greatly appreciated.

[Styrofoam is a brand name for expanded polystyrene (EPS). It comes in sheets and blocks of varying thickness. It can be cut with hot wire systems, or with rotary tools, or by hand, but the hot wire makes the cleanest cuts and least amount of mess. It can be molded, but that requires steam-jacketed metal molds that are not very easy to manufacture at home (at least for most of us).

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[JD_Mortal]

You can purchase Styrofoam pellets, and they do not need a vacuum to expand. You pour about half volume into a mold, and set it in boiling water. The gas in the pellets expands, and fills the mold perfectly. The coating on the pellets softens and they bond to each-other from the pressure and heat of the boiling water.

Cheaper than lexan or plexiglass or other plastics of that nature.

With a vacuum bed, you can only bend sheets about 30-degrees before warping and folding occurs. Normally, molded shapes are made with injection-molding using a 100-ton press, or using a process called blow-molding, which blows a bulb of thick hot lexan into a 3D shape, like a soda-bottle or a vase. (Blow-molding is used to reduce noticeable seams that injection molding usually leaves behind. It is also used to make micro-thin layers, like soda-bottle walls.)

Vacuum-molding with a 3D mold, is nearly impossible with most plastics, mostly because of laws related to plastics. Most plastics require super heating at high temperatures which releases highly cancerous fumes and oils. The fumes you breath, in production, and the oils your customers get on their hands, when they handle the items. (You usually can't wash the cancerous dusts and oils off, they are not normal lipid-soluble oils. They are more like machining oils you would find in a factory. Also commonly used in molding-production, in a chemical called, "mold release".)

Heating plastics to a malleable-state is not the same as heating them to a near-liquid state, required for most molding.

Look into bio-plastics, which are usually more expensive, but more ideal for consumer reproduction at full liquefied temperatures.

If all else fails, on a consumer level, you can always use clear epoxy for making thin, inexpensive, low toxicity, items for resale. (You can vacuum mold the liquid to get full detail and remove bubbles, with off-the-shelf food-sealers and shop-vacs. A little goes a long way in liquid epoxy, as opposed to plastics which will require more industrial vacuum sealers to get any functionality out of the molding.)

Remember, you need an MSDS for every plastic material you use in production, at temperatures near melting, for legal reasons. (They want to know that you know, that you are working and selling cancerous products, and that you have taken the appropriate steps to reduce your customers harm, and made them aware of the dangers. Yes, even for hobbies.)