Instant styrofoam?

Coffee cups and most packing peanuts are two different things. The peanuts are true extruded Styrofoam. The cups are made from expanded polystyrene beads which are fused together in a mould. There is nothing instant about it. The beads are injected into a mould and then steamed to fuse them together. The mould is cooled with water and then the water is removed from the mould and EPS via vacuum. In short it's not a chemical type process. I actually make these kind of products for a living. Cooler boxes, Construction forms, molded packaging trays and blocks, helmets, aluminum casting blanks, etc, etc... Look locally for packaging suppliers, there are many facilities over N. America that make this kind of stuff. Are you looking for a block of material to shape yourself or are you looking to have something manufactured?

Layne Rossi

Thanks for the info, Layne. I was hoping it was something I could pour into molds myself, for limited run items. I dislike some of the characteristics of urethane foam, plus I'd heard that styrofoam is cheaper than urethane.

Based on what Lynn said, you could probably buy polystyrene beads, such as are sold for bean-bag chairs, and do the operation yourself. That would, however, require a mold capable of withstanding sufficient heat, which probably means a machined metal mold.

-Kevin

And a Vacuum pump, a 60 PSI Steam source. The mould also needs a cooling manifold for the water and that bead must have been pre-expanded within 24 hours.... Not a material for a prototype Kevin. Rays best choice if he wants EPS weight and density is to carve a block of foam using hot wire and similar tools. I've done it 3 times for HP nose cones and I'm trying it for CF wrapped fins.

Layne

Phew, yeah, sounds like a hot wire is the way to go!

Most of that is doable, if someone REALLY wants to. Pre-expanding it, though.... Dunno if that's possible at home, or not?

-Kevin

doesnt make sense unless you plan on making them by the millions.