Halloween Pirate Cannon (and Fog Machine Disguiser)

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This Instructable describes the cannon I built to disguise the fog machine I use for my pirate-themed Halloween setup. I was built primarily out of standard 2 x 4 lumber and PVC/ABS plumbing, all available at your local big box hardware store. I apologize for the lack of interim pictures, but I did this project a while ago before I discovered Instructables.

Anyway, The main purpose of the cannon was to hide the fog machine in some context that made sense within the Pirate theme we've had for the last few years. Having the fog come out the cannon as though it were firing seemed like the obvious choice.

Step 1: Designing the Plumbing

For me, most of the fun is in the planning and research. I sketched out some ideas that could be very easily built using simple 2 x 4 lumber. I then went to the local Home Depot and Lowes to see what was available in the plumbing department that would provide the right scale. Once I had all the sizes determined, I started modeling a solution. I'm an Industrial Designer (www.eikedesign.com) so I used Solidworks to determine the plumbing method. I decided to plumb a path from the fog machine exit up thru the bottom of the cannon to exit out the front. I used a large diameter pipe for the cannon body, a smaller diameter for the fog path, and a reducer on the front of the cannon to mate the 2 and to simulate the thick wall of my cannon.

Step 2: Finalizing the Design

Here you can see a Solidworks rendering of the proposed design.

Step 3: Building the Support Structure and the Barrel

The lower support structure is pretty simple. Each layer of 2 x 4 parts is screwed and glued from below to the layer above. I added deep counter bores to keep the screw length down.

The rings on the cannon barrel were made by cutting short lengths of the main pipe, slitting them, sliding them over the main barrel, and gluing them in place. I oriented the slit gaps on the bottom where they are not visible. The end cap is a standard pipe end cap that's been cut way down in length.

To make the flare on the nozzle end, I added a thin MDF wooden ring and then used auto body compound to swipe the transition.

Step 4: Building the Wheels

The wheels were also made from standard 2 x 4 lumber. For these, I used biscuit joints with the glue to avoid the screws. I used stock closet poles for the wheel shafts with small dowels press fit into cross drilled holes in the shafts (not shown in this image, but visible in the final). 

Step 5: Finishing Details

I stained all the wood, and added some black chain and some molded wood detail parts I found at Home Depot to give the cannon some fanciful decoration. I also found a molded resin pirate head in a discount bin somewhere that I believe was originally intended as a paint-it-yourself belt buckle kit. It doesn't show very well in the photo, but I painted it bronze and added it as a cast bronze emblem on the front.

In the original design, I had some simulated strapping that I was going to make from 1/8" by 1" aluminum bar. I ultimately wanted something more Disney-esque rather than historically or structurally accurate so I added some simulated bronze nails using bronze-finished round furniture tacks.

Step 6: Video Demonstration

Step 7: Conclusion

That's pretty much it. I still need to make the straps that hold the cannon barrel in place, and I still may add the strapping to the wheels after all.

I might also add a red light to the inside of the barrel at some point to indicate the cannon firing and provide some dramatic backlighting to the fog. I'd have to make a little electrical harness between the fog machine and the fog timer though to time the light and that may be over my head.

In the photo, I also added a stack of cannon balls made from styrofoam balls painted flat black (the photo is grossly overexposed), along with a barrel that I flamed and stenciled to fit the theme (It says "Gunpowder" and "Barbados").

I didn't include any specifics as I don't know what is available at your local big box store. I'm also a firm believer that you'll get more enjoyment out of coming up with your own design anyway. Hopefully, this Instructable inspires you to do just that. Thanks for looking!

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    35 Discussions

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    MikeV124

    Question 9 months ago on Step 3

    Can you give more details about how you did the flared muzzle? it looks like more to it than just an MDF wood ring and some bondo. How did you make the inside look so nicely tapered?

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    markeikeMikeV124

    Answer 9 months ago

    Oops! Yeah, I kinda glossed over that part. Sorry.

    I cut down a cone reducer like this one (see link below) to fit inside the large 4" pipe. I glued it inside backward so that I could attach the smaller diameter "smoke pipe" inside the larger pipe (see transparent CAD image above). The 45 chamfer inside the cone reducer forms that nice taper inside the muzzle. Once everything was cut and glued in place, I added the MDF ring and bondo-ed everything to form the outer flare, and hide the joints between the cone reducer and the pipe. Hope that helps.

    PS- I can't find a link for a 4" to 1-1/2" cone reducer, although I'm almost certain those are the sizes of pipe I used. I'd check your local BigBox and see what might work for you. That's what I did. https://www.amazon.com/POWERTEC-70136-4-Inch-2-Inc...

    Thanks!

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    jen617

    4 years ago

    Hi there, may I ask how you made the bands across the center of the cannons? Also have you had any success with sound synchronizing?

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    markeikejen617

    Reply 4 years ago

    Sure. I cut sections of the same pipe at about 1-1/2" wide, then slit them along the length. The slit allowed me to open them slightly to fit over the main pipe. I positioned the gap formed by the slit on the bottom of the cannon so you never see it. I then swiped some auto body repair putty around either side of the band to blend it in to the main body, and painted.

    I didn't do anything with electronics or lighting. The cannon was just intended to disguise the fog machine, and it works perfectly for that as-is.

    Thanks!

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    markeikejbonnema

    Reply 4 years ago on Introduction

    Thanks! They are just common round-head furniture tacks available at the big box stores, like these- http://www.lowes.com/pd_58199-37672-532690_4294710882__

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    markeikelm45116

    Reply 7 years ago on Introduction

    The fog machine just sits on a shelf. The cannon with attached plumbing forms a lose fit over the exit hole of the fog machine so there are no hard attachments between the two (somewhat visible in the CAD drawing). You can just lift off the cannon to gain access to the fog machine fill hole.

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    markeike_biohazard_14

    Reply 8 years ago on Step 2

    It's a high-end ($6,000+) 3D solids-based engineering program called Solidworks, which has a built-in rendering program called Photoworks. I'm an Industrial Design Consultant so I use it for work. For something as simple as this, you could use a free CAD package like Google Sketchup and get great results.

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    markeikecablestein

    Reply 8 years ago on Step 4

    Just standard rattlecan paint - primer and semi gloss black. I really like Rustoleum "Painter's Touch" paint. It goes on and levels out really nicely and is pretty durable, but all major brand paints are pretty good. Cannons were cast metal and paint was slopped on to prevent rust, so a really smooth, run-free automotive paint job is not required. The only trick to rattlecan paint from my experience is to ignore what they say about it being "dry to the touch" in 24 hours. Let it cure for at least a week and you'll have a really durable paint job..

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    rbbiggs

    9 years ago on Step 3

    What size (diameter)  PVC pipe did you use, and how long of a piece?  Is the swivel made from 2 inch PVC?
    Also, how wide and how long is the 2x4 base?

    Thanks again for posting this, going to have some fun with my Kids !

    1 reply
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    markeikerbbiggs

    Reply 9 years ago on Introduction

    Sorry for the delay in responding, but I had already put the cannon away for the season. The cannon barrel was made from 4" irrigation pipe with 1.5" inch pipe for the cross piece. The base is 24" long by 10" wide and three 2x4s tall with 7.5" wheels. Thanks for your interest!