Go to the yellow pages...on the Internet look under plastics then narrow it down to foam. You may also try Thomas Register on the Internet. I would guess that you are looking for 1 lb. per cubic foot white foam....styrofoam.

There are plastic suppliers in nearly every part of the country and they have hot wire cutters to size the foam to the thickness that you need. They get the foam in huge billets or make the billets themselves. Then they cut it down to size required. These companies may be in the business of making architectural products, insulation, foam for boat docks, etc. Foam supplying is a huge huge business. So you shouldn't have any problem getting the foam.

Buying from a building supply company is NOT the way to go....unless they have what you want in stock. Shipping charges are AWFUL. You need to find a supplier where you can drive there and pickup what you need.

For example, I recently bought a stock of foam from http://www.gafoam.com/ It is a huge foam company with plants near Atlanta and another up on the East Coast. Look at it for reference...then go looking for similar companies in your part of the country.

Cheers,

Ken Blackwell