"Self-healing," targets are a misnomer: Genuinely self-healing materials are very expensive polymers that return to their original state when heated, but none of these are used in the manufacture of archery targets. So-called "self-healing" targets are made of various closed-cell urethane foams, usually polyurethane. When an arrow is removed, the foam presses the hole closed so that it is virtually invisible. Eventually, the damage will be extensive enough to require replacement, which can cost $250 or more. Fortunately, the clever do-it-yourselfer can produce an inexpensive (less than $15 per target), portable and practical alternative made from materials found at the local home-improvement center.
Cut the material
Cut the insulation into eight 24-inch squares. Plan on using two pieces for each target (producing a 4-inch thick panel), so one sheet of insulation provides enough material for four targets.
Glue two insulation pieces together with spray adhesive. Spray both surfaces to ensure a firm bond.
Glue a sheet of cardboard, cut to the same 24-inch square dimension, to one side of the insulation. This increases the durability of the target and helps stop the arrows.
Glue one of the floor mats to the cardboard. This will be the front side of your target.
Bind the edges with tape. Use two strips at each corner, going from front to back across the stack, is usually enough to keep the target together.
Wrap the block you just made in a plastic or canvas tarp or drop cloth (optional). Doing so catches bits of foam that will fall from the target as it's being used.
Place the 30cm FITA target on or onto the target butt you just made. This size target matches the size of the floor mat panels used.