Dream no more landlubber! This cannon is easy to make, pretty sturdy, and light enough to carry. You can now be the pirate you always wanted to be! Pirate cannon envy no more!
Step 1: Buy the pink insulation stuff
Go to you local hardware store and get yourself one or two sheets of that pink insulation. There are various thicknesses, so try to figure out how big your canon will be, and base the size and thickness on that.
Step 2: Cut!
Step 3: Glue
Glue. The best thing to use is foam core spray. I previously tried liquid nails, and it just doesn't work. Not enough oxygen gets to the inside of the foam squares for it to glue. This stuff is made specifically for the foam board.
The can is simple, spray each square, wait 1-2 minutes, press together, and repeat. Once the entire stack is glued, put it somewhere safe and come back tomorrow for the next step.
Don't do anything stupid like putting a giant ceramic flower pot on the top of this stack thinking it will keep everything compressed. The flower pot will slide off and and it will make a mess. Yar!