ways to cut foam
Cut polystyrene foam with an electric kitchen knife. Use an electric kitchen knife, such as a carving knife or a fish fillet knife, to create clean cuts in Styrofoam. Place the electric knife on the foam along the desired cutting line.
But instead of plunging the blade completely through the foam, only cut a slice about 1/8â³ to 1/4â³ of the way through the foam; just enough depth to keep the blade moving without having to force it. It is also very important that you make your shallow cuts the entire length of the foam.