My friend had given me an empty Pringles can to add to my "stash" of things I might need for making pirate decorations. Well, that worked perfectly for the side pieces of the cannon.
My husband had bought a ready to eat salad from the grocery store-- that worked out perfectly to create a rounded end on the non-firing end of the cannon. Once the basic shape was formed, it was simply a matter of adding the finishing touches. I added pieces of crinkled tissue paper on the cannon, the cardboard 2 x 4's and the wheels too.
Once the tissue paper had dried, all I had to do was paint it and put it together. Now that it is finished, it is going to hang out in my garage until needed.
Cheryl