Please be aware that many floral foams are toxic and breathing in the dust that carving produces is very hazardous to your student's health. Watch out for those with asthma even with the non-toxic stuff........
I have done Styrofoam carving and it was fun for them. We used hot knives and sand paper. It depends on the type of foam you have I used surfboard foam because it was stiff and could be cut with a saw and sanded. This was in High school though, so you would have to use less dangerous tools. Look for dense foam and use tools they can handle. We left them white and also airbrushed over them when they were sanded smooth. I got the foam from a friend who makes surfboards and these were pieces from a crashed board that he just stripped off the fiberglass. I was lucky to find this.
Art teacher, Leigh High School, San Jose, CA
Website: Leigh Art
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