The Original Potato Cannon





Introduction: The Original Potato Cannon

About: I liked designing and building things long before I became an engineer, now I get paid to do it!

In this instructable I'm going to teach you how to build the original hairspray powered potato cannon. Sometims it is also called a potato gun. Making this cannon takes about an hour and $30. The finished gun can shoot potatoes over 100 yards!!!

Step 1: The Materials

Building Materials
-5 feet of 1.5" ABS (DWV) pipe
-2 feet of 3" ABS pipe
-A 3" to 1.5" reducer
-A 3" threaded adapter
-A 3" end cap
-A BBQ ignitor (+1 Screw)
-ABS cement

-Cheap aerosol hairspray
-Potatoes or similar legumes


Step 2: Assembly

-Cut the 3" pipe to about 13" or a size you prefer (the larger the combustion chamber; the more gas; the more boom)
-Make sure the reducer fits over the pipe
-Spread some ABS cement on the inside of the reducer and outside of one end of the pipe, slide the reducer onto the pipe with a twisting method
-Repeat this for the threaded adapter
-Repeat this for the barrel (5' of 1.5" pipe)

Make sure your gluing is done properly, you dont want it to explode.

Step 3: Install the Ignitor

You probably saw in the last step a silver BBQ lighter attached to the side of the pipe, I tried using this, but it wasnt working, so I bought an $8 ignitor.

Drill a hole in the 3" pipe for the metal lead from the ignitor to fit, mount the ignitor using screws provided, you can slop some glue around the hole to make sure there wont be a gap where the flames will shoot out and burn your arm......

In order to create the arc (spark) to ignite the gas, there needs to be a metal contact between the lead from the ignitor and the metal chasis of the ignitor.

If you mounted the ignitor with bolts into the pipe, bend the metal lead to be within 1/4" of the bolt to make a spark,
I however put another screw in from the other side, but had to run a piece of wire from it to the metal chasis.
Both methods will work.

Step 4: You Are Finished; Firing

Let the cement cure for a couple hours.

-Unscrew the end cap
-Force a potato into the barrel (this is easier if you sharpen the end of the barrel with a file)
-Pack it down with a broom, make sure its still inside the barrel, and not the combustion chamber
-Spray some hair spray into the 3" pipe for 2-3seconds
-Quickly screw the end cap back on
-Point it at a 45 degree angle to maximize range and push the ignitor

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Can I use a 5 Liter bottle for the combustion chamber? I have a pipe the right diameter for the barrel but not one for the chamber.


Can you cut the 1.5" pipe to 3 feet ,instead of 5?

2 replies

Sure you can. It will reduce the range, though.

bcrylonitrile butadiene styrene. it is sold in hardware stores, and looks like black pvc

*acrylonitrile butadiene styrene

Consider removing your cap before you shoot it.

I would like to make one of these, except mine will launch marshmallows, instead of potatos. do you know if this is possible by just getting a 5 feet of 1" ABS (DWV) pipe instead of a 5 feet of 1.5" ABS (DWV) pipe?

2 replies

*and a A 3" to 1" reducer instead of a A 3" to 1.5" reducer

Maybe, but marshmallows tend to stick. This creates pressure buildup, which tends to blow the marhmallow to pieces. Marshmallows also will get smothered by the rapid acceleration through the pipe. A simple solution would be to use a reducer smaller than the marshmallow, and a slightly larger pipe.

Cool, were do you get stuff to make the gun?

I've made one, except I did go with steel pipes, silicone, rivets, and duct tape, and I'm using starter fluid as a propellant. Packs a hell of a punch.

Quick question, what's the best way to make a pressure valve so that if I accidentally use too much combustables it won't explode on me.

Also what will any type if BBQ igniter work

1 reply

Firing your kids out of it

It really doesn't matter as long as it is the style with the long barrel and a trigger