How do you shape styrofoam?

Question

I am trying to make a skeletal model and I plan to use spray styrofome. How would I mold it into the shape of a bone.

Answer 1

Why not try some other material?

You might get away with polymer clays if it's not too big...
http://www.dickblick.com/categories/polymerclays/

Answer 2

Unless you are going to make a lot of the same bones, making a mold is not the way to go. First you would have to sculpt the bone the way you want it. Then make a plaster two part mold from the bone you made. Prepare the mold with a mold release and pour in two part AB urethane foam. If no bones are alike use a dense polyethylene white sign foam or blue or pink extruded insulation foam. It can be carved and sanded. Coat with elastomeric to make it more durable. Or there is a product called A-Poxey Sculpt which is a 2 part water base material that can be smoothed over the foam to make it hard. Another product is Friendly Plastic which can be shaped into bones. Soft wood like white pine or balsa wood can be used also. You can make a skull with A-poxey or a material called Sculpty by applying it over a rough carved plug of foam. Use a heat gun to harden the Sculpty.

Answer 3

Spray Syrofoam...like spray insulation?

I would make a mold with modeling clay and squirt it in it. Or you could spray it into the rough shape of a bone and use a serrated (steak) knife to carve it into shape after it hardens.

Answer 4

As I learned to my dismay, carving spray can foam insulation is a real hassle. And it isn't Styrofoam which flamable styrene in either bubble foam or expanded bead form.

Answer 5

use a spoon.