Thread: Foam Carving - Cannon

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Ok, so my grandpa and I are trying to build a naval/pirate cannon for my haunt. We want it to be functioning so we've built a potato gun and are trying to build onto it with pink insulation foam. We've started to cut out circles and glue them together onto the skeleton (spud gun). Now we've sort of hit a road block. We don't really know how to go about carving this cannon. Does anyone have any insight as to how we could go about this? I know this is a ways down the road but how would someone "treat" the foam after it is carved? I've read somewhere online that suggests fiberglass. Is this the way to go? Is there any easier ways? Stronger ways?

I remembered seeing something like that when looking into some foam work. I think this might be just what you're looking for

Pirate Cannon - A working replica of a naval cannon that fires pneumatically - Instructables - DIY, How To, craft, offbeat


hope I did that right... if not you can cut and paste.

Carving? Like what tools to use?

I use a bread knife from my kitchen. It's great! Once I get the shape, an electric sander, then by hand. Not sure if that's what you were asking.

As far as treating it. I paint, paint, and paint. Then if I want to waterproof, use a sealer (which I've actually never done... yet).

I followed the basic process in the instructables, with a slight modification. I drew the cannon profile out full size on paper. I then "sectioned" the drawing into 2" and 1" sections.

I then used a circle cutting jig with my tilt head bandsaw to cut circles of foam which had the angle and diameter as shown by each section of the drawing. I then used a hole saw to cut the center out of each piece for the PVC tubes to stick through.

You can then use epoxy to glue all the stacks of together. I also used fiberglass cloth and epoxy to cover the foam. You CAN NOT use fiberglass resin for coating the foam, it will melt it. You have to use epoxy, very expensive.....



Lee

I can not seem to post pictures, but I created an album "ltkhoover" with pictures of the cannon I built using the info in the previous post. The cannon is plumbed for both compressed air firing and/or fog machine. I did not think the compressed air added anything, so I did not use it at Halloween. The cannon is fired by an animatronic Blucky who turns his head, turns at the waist and then drops his arm to "fire" the cannon with an LED tipped "match".

Lee

I've never used latex before but do you think that would work instead of fiberglass? If so, would you put it on before or after painting?

how would i go about using said epoxy and fabric method? how expensive are we talking?

Would anyone have any ideas for colors to paint my cannon? I want it to look as authentic as possible. I was thinking a silver with black misted over it. Any thoughts?

Black... if you want to scuff it up a bit, use some silver or whatever, but I believe black is authentic.

Originally Posted by neojacksparrow

how would i go about using said epoxy and fabric method? how expensive are we talking?

Not sure what you mean about using Latex. I suppose you could use hot glue to glue the foam togeher and then paint with Latex paint. It would probably look OK, but would not be durable.

To epoxy coat, you lay fiberglass cloth on the foam and then saturate it with epoxy. My cannon took about a quart of epoxy to glue everything together and then cover with epoxy saturated fiberglass cloth. Not sure what epoxy is going for now. A year ago, a gallon was close to $90.

Look on the web for instructions on boat building. They cover wood with fiberglass cloth and epoxy all the time. Should be some good photo's and tutorials.

After the epoxy dried, I painted mine flat black. I then splattered/fogged red oxide primer lightly on it. Gave it a very nice rusted metal look. I have had multiple people believe that the cannon barrel is real.

Good luck with your project.

Lee