How to Make a Potato Gun Launcher

Are your ready to have some fun making a potato gun? Let's sure hope so, because this is the full guide to building a potato gun capable of launching a potato 250 yards or more. That's well over two football fields in length! You can either read our step by step instructions below or Watch the Instructional Video.

1. Before you start to make a potato gun launcher, check the laws in your area because these guns aren't legal everywhere anymore.

2. Make sure that your ready to invest about 30 dollars or so for the parts. No worries, this baby will be well worth it!

3. What to buy:
* A grill ignition kit (The little clicky red button on the grill)
* A 4-inch diameter PVC 90 degree elbow (Or just a section of four inch pipe)
* A fitting adapter for the elbow (Or pipe) with threads for a cap
* A screw on cap
* A 4-inch to 2-inch PVC adapter
* A 4 foot long section of 2-inch PVC pipe.
* A few cans of aerosol hairspray
* A bag of potatoes

4. First, put the threaded adapter on the elbow, and screw the cap on it.

5. Put the 4-inch to 2-inch adapter in the other end of the elbow

6. Put the barrel in the 2-inch end of the adapter, if it doesn't go in, lightly tap it with a hammer. Make sure it is flush when you are done.

7. Drill a hole in the side of the elbow(from here on out, referred to as "The Chamber")

8. Stick the prong that came in the grill ignitor kit in the hole, and fasten it with a screw.

9. Pick one of the wires that came in the grill ignitor kit, and fasten it to the prong. Fasten the other end to the bottom of the grill ignitor.

10. Tape the grill ignitor to a comfortable place on your cannon, this will become the trigger.

11. There is another metal tab showing on the outside of the grill ignitor, fasten the other wire to this and let it hang while you do the next step.

12. Screw a screw into the side of the chamber so that it is a sixteenth of an inch away from meeting the prong on the inside.

13. Fasten the wire you let hang from the grill ignitor, to this screw on the outside of the chamber. When you click the grill ignitor, you should see a tiny spark jump across the prong to the screw.

14. Don't let your body touch any of the metal parts, your body will take the shock and you won't get a spark. Ir helps to cover up all of the wiring with electrical tape.

Loading the gun

1. Get a potato and wedge it down the barrel with a broom or other pole. It should be a tight fit.(Ideally, the barrel should trim off the edges of the potato when you put it in)

2. If you don't have any potatoes, you can load the gun with anything smaller than the bore. All you need to do is stuff a wet rag down the barrel before loading your ammo. This step is crucial, as it forms a tight seal and prevents pressure from escaping around the object. If desired, you can put another wet rag in after the ammo to keep it from falling out of the end of the barrel.

Firing The Cannon

1. Load the gun as directed above

2. Unscrew the cap.

3. Get ready to race the clock.

4. You have to do this next step in 10 seconds or less.

5. Spray hairspray into the chamber for about 5 seconds (you've better hurry, half of your time is up!) Screw the cap back on, but DON"T CROSS-THREAD IT!!! Prepare for a kick and push the button on the grill ignitor.

6. Watch that potato soar.


There are a few reasons why your potato gun might not work.

* The spark is not traveling through all of the wires.(Check all of the connections)

* Your body was touching something metal when you pulled the trigger.

* You waited too long to fire. This mistake is the most common. If you wait more that a few seconds after spraying the hairspray in the chamber, the fumes will evaporate, and you will be left with a sticky hairspray glob in the chamber.

* Your didn't clean your gun after every shot! There will be a puddle of hairspray in the chamber after you fire (only the fumes catch fire) You don't want the leftover glob of hairspray to stay in the chamber, or it will harden around the prong, and your gun will not make a spark. Also, clean it immediately after firing, otherwise the cap will get stuck.

* You have a weak seal around the projectile. Make sure it fits tightly in the barrel.


* Use common sense!!
* Always check your local laws before firing.

* Never fire at anyone or anything. The best place for a potato gun is in a wide open field without young children around.

* Don't fasten any pipes together except the PVC cap. The gun is designed to fall apart if it reaches explosive force. If anything is fastened that is not supposed to be, the gun could explode.

* Use this gun at your own risk. It is not a toy


* Experiment! Instead of dealing with wiring up a grill ignitor, just hook a safety pin to the tab on the side and bend it towards the tip. Sharpen the end of your barrel to perfectly trim off the edges of the potato. Put a screw on the bottom of the barrel to prevent you from loading the potato in too far. The possibilities are endless.

* Accessorize! Add a strap to carry it, a water bottle holder from a bike to carry your hairspray, or make a ramrod holder out of film canisters. A good way to carry extra ammo is to fasten nails on your gun to stick extra potatoes on.


Jack B said...

thanks for the great tutorial. Right now I'm working on building one for my physics class

Anonymous said...

yeah boy science fair here i come

atul said...

ATUL BRAND- Twenty years experience pipe manufacturer and supplier of Delhi/India, provide quality pipe manufacturing in pvc pipe, pvc conduit pipes, conduit pipes, pvc conduits.

ATUL BRAND - PVC Pipe, PVC Conduit Pipes said...

ATUL BRAND- Twenty years experience pipe manufacturer and supplier of Delhi/India, provide quality pipe manufacturing in pvc pipe, pvc conduit pipes, conduit pipes, pvc conduits.

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