I've tried that, but you're correct, the glue just doesn't sand well and is hard to cut. If you have a textile store near you, ask them about foam bolsters. I get the ten inch ones and cut my heads out of them. I know it's a project to find sheet foam that is thick enough for carving one piece heads, so I found that these are a perfect alternative. They're round, but large enough to make a one piece head from.