Step 3: The main barrel
Everything is then built onto this barrel, starting at the front. Cut out a suitable sized piece of foam and hot glue it around the barrel to build up the shape. I used an old exercise mat about 8mm thick which was easy to cut with a scalpel but also meant it damaged easily and deforms if in contact with the glue gun nozzle, so be careful! Shaping the front piece of foam is done carefully with a scalpel, it'll get tidied up later.