Pirate Cannon - A working replica of a naval cannon that fires pneumatically

Step 5 Glue it Up

Draw a reference line on the foam before you take it out of the jig. You could number the layers also, but I didn't have any problems. To glue the layers I used a Liquid Nails product rated for foam and I have used "Gorilla Glue" before with sucess.

Use a piece of pipe to help align the barrel slot and stack the layers on it. I added some wieght to the top and let the glue cure for a couple of days.

After I double checked that the layers were bonded, I cut the slot for the firing mechanism, which I should have done before the glue was applied. You won't make the same mistake.

To shape the cannon, I left the foam on the pipe and sanded with 60 then 140 grit sand paper.

The next layer was "Foam Coat" a commercial product that worked well, but in the future I would fiberglass the foam if the project would see a lot of use (like this cannon). For a prop that didn't need to be too durable I probably coat the exterior with plaster of paris or something similar.

Because the foam is coated, any paint will work. Use a latex based paint if it contacts the foam directly or it will melt your project.