A long blade utility knife;
How to cut styrofoam ball in half. Sanding and smoothing styrofoam step 1 cut or trim your styrofoam project pieces. You can cut a round styrofoam ball in half by tracing a line along its equator with a. You can cut a round styrofoam ball in half by tracing a line along its equator with a sharp pencil.
Rub the cut edge of the scrap piece against the cut. Divide round styrofoam balls by cutting them down the middle.