Things You'll Need
Sharp knife, short, non-serrated blade
Pen or marker
There are many craft patterns available for Styrofoam ball projects. The Styrofoam balls may need to be cut into halves, quarters or slices for some of the projects. You may even find a project for a hollow Styrofoam ball with a diorama or miniature floral arrangement inside of it. It is important to learn how to cut Styrofoam balls to save on waste and breakage.
Place a Styrofoam ball on a newspaper-covered work surface. Measure and mark the area that needs to be cut or removed with an ink pen or marker.
Cut a small area on the ball with the sharp knife. Slice into it and carefully cut away excess.
Cut the measured marks on a larger Styrofoam ball with the sharp knife. Cut straight across the marking of the entire area you need to cut. Go back over the area and cut more deeply. Cut it all the way through, if possible, or continue with the next step if not.
Pick up a piece of florist wire in gloved hands. Place it directly over the previously cut mark on the Styrofoam ball. Pull the taut wire firmly down through the ball and slice it in two pieces.
Be careful not to hold a Styrofoam ball too tightly when cutting it. You can crush it.