Sorry jt

       I have used both polystyrene and Styrofoam for many, many props and sets. I have made everything from replicas of old sewing machines for "The Pajama Game" to an 8' X 12" Sphinx face for "Joseph and the Amazing Technicolor Dreamcoat" out of 2' x 4' x 8' styrofoam blocks. For both I have made my own styrofoam heat knife. This I use to make initial large cuts. Then I use a Surface Forming Multi-Rasp Shaver, the small plastic handled, removable blade kind, for rough shaping. For the polystyrene I use a fine sand paper to get a very smooth finish. The styrofoam will not ever get this same finish due to it's composition.
       You can make virtually anything you want out of the stuff. When using a heat knife or power tool with it, you MUST have proper ventilation and wear a respirator. Because when heated it releases harmful dust and vapors. You should  use a respirator when sanding the stuff also since the fine dust can get into your lungs and cause numerous issues like a Heart Trauma ( this from experience is not very nice. ) The dust clogs your lungs and basically causes a heart attack that is not due to heart related medical issues. In my case I carved and sanded an entire laced wood looking set for "The Sound of Music" in a shop with no ventilation and did not wear a mask. It put me out of commission for a few months but luckily there was no permanent damage.
      To make the foam thicker or attach it to things or things to it,you can use "Spray 70" for styrofoam or "Spray 80" for polystyrene. This is a spray contact cement. The number indicates strength and for the foam lets you know how much it will eat it away. If used according to the instructions, it will bond the pieces as one. But a warning, like all contact cement, once it touches it is GLUED and cannot be moved. So to make a thicker working piece, I cut them to rough size and glue them before carving. The glue will not carve at the same rate so do not try to smooth seams with rasp. Gently sand the seams as good as you can. Once sealed and painted they will not show.
      To help the finished product withstand some abuse I base coat it with  Snow Roof. A white elastic latex paint. Then you can give it any treatment you desire including spray paint, which without a latex base coat would eat the foam.
      I LOVE the stuff.


Edited by ZFix2000 - 11/13/11 at 11:12am