Chipping foam
 Size range in wood chipped foam  Bearcat wood chipper |
I borrowed my brother’s wood chipper to test chipping foam. I think wood chipping foam will work if a screen is added to the chip exhaust to keep the larger pieces of foam inside the chipper until they’re reduced sufficiently in size to exit the screen. The unscreened size ranges from 3/4″ to big dust. Adding a screen (maybe concrete lath?) may be all it takes to get the right size for making EPScrete.
Dan’s machine is a fairly expensive heavy duty chipper. I can’t speculate on what another chipper’s result would be.