G'day. I'm making a master for vacuumforming a fuselage. In the past I used Bondo two part putty (automobile stuff), which sets up quickly and is solid enough to take the vacuum form. However, once it sets it is VERY difficult to sand quickly, and dust is everywhere. I've tried regular (grey) modeling clay, but I don't think it will keep its form before crumbling. I was thinking of Skulpy, but that's about $50.00 a container (the fuselage is 14 inches long, about 3 inches high and 1 1/4 inch deep). Does anyone have suggestions? I was thinking of Plaster of Paris. Don't recommend the "take a block of wood and whittle . . ." route-- wood does not like me. Thanks~!