One of the best and the fastest ways of cutting foam rubber, especially thick pieces, is with a common electric cutting knife. An electric knife will make a clean, smooth cut and will cut large areas at a time (as opposed to the multiple tiny cuts which often must be made with an X-acto or utility knife). If you routinely cut foam, especially thick pieces of foam, then you would do well to invest in a good electric knife.
Things You'll Need
- Electric carving knife
- Felt-tipped marking pen
- Cutting table with slit
- 2 flat 1 x 4-inch boards
- 4 C-clamps
Construct a simple cutting table with a slit in it so the blade of the electric carving knife can extend below the surface of the table. This can be as simple as two flat boards with a small space between them laying across two sawhorses.
Mark the foam with a thin-tipped felt marking pen.
Lay your foam on your cutting table with the cutting line face up (so you can see it) but directly over the center of the slit in your table.
Lay a 1 x 4 on either side of the cutting line on your foam and use C-clamps to squeeze the 1 x 4's and your cutting table together. This will compress the foam. You want your foam compressed with the cutting line directly above the slit in the table.
Hold your electric knife at a 45-degree angle and turn it on. Bring it down slowly on the cutting line and allow the blade to cut smoothly through the compressed foam. Cut with the blade of the knife rather than the tip. The tip of the blade will extend down through the foam and through the slit in the table so the knife can cut all the way through the foam with one smooth slice.