Step 1: Materials
Camera Body Cap (Available at ebay for Nikon and Canon).
PVC pipe slightly smaller in diameter than the body cap (I used 5cm / 2" for nikon cameras).
Sheet of foam (Ethylene-vinyl acetate) 5mm / 1/10" thick.
Mate black spray paint.
Crazy glue or any other cyanoacrylate based glue.
A ruler, a drill, circular saws, scissors, hot wire and other cutting/measuring instruments.