Expanding foam beads

[TinkerDJ]

When i was in shop class in high school, along time ago, we used these little foam beads, put them in a metal shell, put a special clamb on the two halves and submersed it in boiling water. When it was done we got a foam skull. Now that i am casting aluminum there are projects that i would like to make a master mold out of aluminum then use the beads to make blanks for lost foam casting. I am having a horrible time finding a dealer for these beads, i have been through google and yahoo looking for the beads. If anyone has an idea where these can be got please send me the link or email me. I know this is how general motors actually casts some of its engine blocks and components, thats one of the things i have run into going through searches so its not like a lost art or something. If this sounds desperate it is. It will save me piles of time duplicating parts to cast.

[gama53]

Try these guys:
https://duckdeco.dkgnet.com/appieshop/index.cgi
I've made plenty of decoys with it but don't know if it will vaporize during casting.

[ynneb]

http://www.delviesplastics.com/polys..._and_molds.htm

[WayneHill]

.. Removed by Wayne

[MHINK]

try a google search on "eps" or "expandable polystyrene" and manufacturers
-Mark