I once used puzzle mats from Harbor freight to make a seat. It's closed cell foam. But it was also difficult to glue with Weldwood contact cement ... the volatile variety ... the glue didn't wanna stick to the foam ... and it was pure heck to shape using everything including sand paper, Dragon Skin, Sureforms, belt sanders, grinders and rasps. I could score the heck out of the surface but the little strands of foam just held on for dear life and were very difficult to abrade off ... never seen anything like it. I'd say it took 3 or 4 times longer to shape than mini cell. So if anyone wants to try it ... don't use the same stuff I used.

Ken Blanton

: It is definitely closed cell foam. I think this particular example
: is sold as a yoga mat or camping mattress.