How to cut foam board insulation?

Answer 1

When getting to work cutting foam for a do it yourself project, it’s essential that the right selection of cutting apparatus is applied. Scissors, garden shears, and even some knives leave rough, jagged edges that will ruin the quality of the foam and eventually wreck the finished work - if not, severely damage it. The solution to this problem is simple: an electric meat carving knife.

To begin, take measurements. Check your work twice, because you don’t get a chance to cut twice. Write down your measurements and then write them down again. There is very little margin for error when making cuts - especially free-hand cuts, and it is all too easy to make one slip of the hand or cut along one poorly measured line. In some cases it is possible and preferred to trace the object you are replacing. If this is the case, place the object on your foam and trace along the outside of the object like a stencil.

Once you are confident that your measurements are accurate, transfer them to the foam. Using a pencil or chalk, along with a straight edge, physically mark the foam with an outline of what you are going to cut. Like with the initial measurements, double and even triple check. There is no room for any error.

When you are ready to make your first cut, place the foam on a flat surface that is a little higher than waist height. Turn on your electric meat carving knife, and turn the setting to high. Make the initial cut with the electric meat carving knife facing away from you, and guide it slowly along the outsides of the stencil you created on the foam. If you have to do a sharp corner, curve, tight angle, or a circular pattern, it is often easiest to make a rough cut outside of the pattern and discard the excess foam first. This will allow you more room to maneuver the knife around a sloping curve or take a fresh stab at a new angle.

When you’re finished, examine your work. If there are areas where you didn’t guide the knife quite straight, shave off a little more to correct your line. Same with curves - if your slope isn’t quite right, use the knife to make it smoother.

Answer 2

electric carving knife, jigsaw,drywall or other handsaw,very very carefully with table or skill saw[kicks back],sharp razor knife