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

3 People Made This Project!


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524 Discussions


4 years ago

Also what will any type if BBQ igniter work

2 replies

I used a bare piezo element from a lighter and it still works


2 years ago

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.

1 reply

Drill 3-4 small holes(3mm or so) in the combustion chamber but be careful not to keep your hand near those holes while shooting it. Or you can get a proper pressure valve but it would need a lot of maths to find the right pressure. Or drill a bigger hole, about 7 mm in the chamber and seal it up with epoxy. If the pressure is too high, the epoxy will break and the pressure will come out the hole.

Drill some holes through the sides of the cap and the end of the combustion chamber so you can stick some nails through. Or just use a ton of epoxy to seal the cap and mount a bottle cap somewhere on the combustion chamber with another ton of epoxy for fast and easy loading, like I did.

Consider removing your cap before you shoot it.

plz tell me if I'm mistaken or not, but the ignition chamber should be 2ft long right?

1 reply

Mine is like 0.5ft long and it works great. The bigger the better, but I think 2ft is an overkill.


Question 3 months ago

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.

2 more answers

you probably want to use PBC or ABS so it doesn't blow up but it could still shoot if you dont put alot of lighter fluid in.

I tried putting spray in a few bottles and igniting it. Most of the times the bottle only got really hot, but sometimes it would burn slower and melt the bottle. Meanwhile I have built a proper cannon with pipes. Works great, but I had to fix the cap with a few nails so I can remove them to reload the cannon but the cap doesn't shoot out and decapitate my nephew (almost happened). But removing the cap and putting it back was very difficult and I needed to do it as fast as possible so the spray doesn't condensate and not ignite. So I took a bottle cap and mounted it on the bigger pipe with a ton of epoxy for easy loading.

i think it will still fire fine but the potato probobly just wont go so far

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