I have four sheets of 4 foot by 4 foot foam. 3 inches thick. I bought it for use as the base for custom made motorcycle seats. This stuff can be cut with a razor blade or shaped with a wood rasp, sometimes I even use a simple old bread knife to cut it. Harder than the normal yellow upholsterer's foam but of course softer than wood or other stiff materials. Very happy with how workable this material is. Being a newbie to the CNC world, I am not sure of its machining qualities. Will add to this post when I find the material specs. Will post a video too.
Please advise if this is wrong forum. I'm just looking for a buyer for these pieces and am not in business of reselling foam.