Polycarbonate isn't all that expensive, at least in small quantities. If you go to the plastics dealer, they'll have a bin full of scrap that you can rummage through and buy for a few cents per pound. Lots of little pieces and bits that are handy for bracketry and the like. You're not going to find big 12x12x12 inch hunks though.
Distinguish polycarbonate (PC) from acrylic (PMMA) by surface hardness. Trying to scratch it with a key will dent PC and not PMMA. A bit of practice and it's easy. They also smell distinctly different when cut.
Polyethylene is very cheap and a good insulator. It doesn't glue for beans though, you have to either bolt it or thermally weld it. Standard white plastic cutting boards work quite well
Created on Tuesday, April 24, 2001 1:49 PM EDT by James Lux