One method of cutting thin sheets of Styrofoam is to use a utility or razor knife. Users have a variety of other tools from which to choose, including a serrated knife, an electric knife, dental floss or an electric hot wire cutter. Cookie cutters also work to cut through thin pieces of foam for cookie shapes.
To cut the foam using dental floss, cut a 12- to 18-inch length of the floss, and wrap it around the forefinger of both hands. Move it in an up and down motion to saw through the foam. The serrated or electric knife works well for thicker sheets of foam or when cutting several sheets to the same size.
Several types of electric hot wires or hot knives are available to cut the material. Most of the wire cutters use a nickel-chromium wire that resists the flow of electricity to create heat. The wire becomes hot enough to melt through the foam and cut it. If there are minor imperfections in the shape after cutting with any of these methods, a scrap piece of foam provides enough abrasion to shape the piece after cutting.
Styrofoam is an expanded type of polystyrene that is lightweight and easy to shape and form. It accepts acrylic paint, but solvent-based paints can dissolve the cellular structure. Crafters can glue pieces of foam together using white glue or a low-melt glue gun.