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PART 1: https://www.halloweenforum.com/threads/how-to-make-a-realistic-cannon-part-1.79204/

PART 2: https://www.halloweenforum.com/threads/how-to-make-a-realistic-cannon-part-2.79205/

PART 3: https://www.halloweenforum.com/threads/how-to-make-a-realistic-cannon-part-3.79207/

PART 4: https://www.halloweenforum.com/threads/how-to-make-a-realistic-cannon-part-4.79208




If you read the first part of my thread, you know we're working on a realistic but lightweight cannon like this...


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We've already made the body of the cannon, a tapering cardboard tube, now we're going to form the muzzle section.

I puzzled over this for while before coming up with this solution. Pink foam. It's the best stuff for making props and it's cheap.

Basically, the muzzle is a series of donut shaped pieces of foam stacked over a lenth of ABS tubing. The inside of the donuts is the exact diameter of the tube, but the outside varies to give the muzzle it's characteristic flared shape.


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It's best to slide all your sections of pink foam onto the tube while the tube is standing up. This way, they all go on nice and square. You can use foamboard adhesive, available where you buy your pink foam, to glue it all together.

Now the fun part. You want to muzzle to have a nice smooth shape. But the pieces of foam are square sided. The best way to shape it is to spin the whole thing. Like you would on a lathe.

I figured out that if I hot glued a temporary plug of wood in each end of the pipe, then drilled a hole exactly through the center, I could insert a dowel that would act as my lathe.


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I just attached one end of the dowel to my drill, clamped the drill down, inserted the other end of the dowel into a piece of wood with a hole in it that I also clamped down, and spun the whole thing. It works great!!!! All you need is some course sandpaper and gentle pressure and you can shape the foam perfectly as it spins. It might take some trial and error, but the raw material is cheap.

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Once you get it looking smooth and the shape you want, insert it into your cardboard tube at the narrow end to test the fit. It should fit nice and snug into the tube. If it's too big, just sand it more.

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Once you've got it, take out the two wooden plugs, squirt some latex caullking around the are where the ABS meets the foam, and the muzzle is ready to be glued in.

One thing though. The length of ABS might need a support inside the tube, especially if you've kept it long. The best thing to do is cut a support disc and glue it inside the tube.

Next, we'll talk about how to add more details to the cannon.

Arrrrrrrrrrrr.....
 

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What size of ABS Tubing did you use for the inside? Also where did you purchase the Pink foam?.....I went to Home Depot and they looked at me with a deer in the headlights look....LOL!
 

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I can recommend contacting an audio supply store for speaker cabinet porting tubes. Online you can order them from Part-Express.com who stock vent port tubing in various sizes. I have some 2.5" and 3" tubes, 4 feet long each. Cheap enough, heck the shipping was more expensive than the product.

Something to mention here about that tube, if you intend to make a fogging cannon barrel or do the ol' compressed air spudzooka boom gun, make that internal tube run the whole length of your cannon. Then you can run whatever special effects into the back of the cannon and it'll reach all the way through.



By the way.... the aging and rust pits in your cannon are SPOT ON! I do believe you've studied an old cast-iron car axle or two as research? Heh heh....
 

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I can recommend contacting an audio supply store for speaker cabinet porting tubes. Online you can order them from Part-Express.com who stock vent port tubing in various sizes. I have some 2.5" and 3" tubes, 4 feet long each. Cheap enough, heck the shipping was more expensive than the product.

Something to mention here about that tube, if you intend to make a fogging cannon barrel or do the ol' compressed air spudzooka boom gun, make that internal tube run the whole length of your cannon. Then you can run whatever special effects into the back of the cannon and it'll reach all the way through.



By the way.... the aging and rust pits in your cannon are SPOT ON! I do believe you've studied an old cast-iron car axle or two as research? Heh heh....
Thanks "Bryan316" for the information....Much appreciated!
 
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