Make a Potato Gun

It’s always fun to build something with your hands, and even more fun to build something that you can shoot! This is the full guide to building a potato gun capable of launching a potato {{safesubst:#invoke:convert|convert}} or more. Make sure to follow all necessary safety precautions. Although it is only a potato, you can really injure yourself or others.

Steps

Preparing to Build Your Potato Gun

1. Check the laws in your area beforehand. Potato guns aren't legal everywhere, and legality may change significantly from county to county, so check with your local authorities to make sure you aren't breaking any laws. You don’t want your neighbor calling the police on you because you’re firing potatoes around in your back yard.
2. Save up money. Parts for a potato gun will cost somewhere between $20 and $40, depending on where you shop. Check the bargain areas of your local hardware supply store for great deals, or use the internet to find deals all over the world. It doesn't need to cost and arm and a leg in order to make a potato gun, but you’ll need some extra cash.
3. Make a shopping list. It’s nice to have all your materials set out for you when you begin building. Your shopping list for a potato gun will include the following items.
   • 1 grill ignition kit (The small red button on the grill that clicks)
   • 1 4-inch diameter PVC 90 degree elbow (or just a section of four inch pipe)
   • 1 fitting adapter for the Tee (or pipe) with threads for a cap
   • 1 screw on cap
   • 1 4-inch to 2-inch PVC adapter
   • 1 4 foot long section of 2-inch PVC pipe.
   • 2-3 few cans of aerosol deodorant (for the butane)
   • Some form of glue or other adhesive (optional, but recommended)
   • 1 bag of potatoes

Building Your Potato Gun

1. Put the threaded fitting adapter on the elbow. Now screw the cap on it. This is a simple step – you’re basically just combining two component parts. The threaded fit adapter is the part of the pipe that has those little ridges inside of it. These are called threads. Refer to the video above for visual instructions.
   • You can also use glue if you worry that the pieces might stay connected. Spread some glue around the edges before connecting the two pieces. Don’t use too much.
2. Connect the adapter. Move to the other side of the potato gun and fit the 4-inch to 2-inch adapter in the other end of the elbow.
   
   
   • Once again, you can use glue for this step if you feel more comfortable with the structural integrity of the gun.
3. 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. Don’t tap so hard that you break the pvc pipe.
   
   
   • This is one step where using glue is recommended. The barrel undergoes a lot of force when a shot is fired and it isn’t as snug of a connection as the other parts.
4. Drill a hole in the side of the elbow. From here on out, the elbow will be referred to as the chamber. This is where you’ll hold your potato projectile eventually.
   
   
   • Make sure your chamber is neither too long nor too short. Too long of a chamber and your spud will sputter out of the chamber too slowly; too short of a chamber and the spud will disintegrate before you know it.
5. Wrap your wire around the spark generator. The spark generator is the piece of equipment you bought that will generate a spark. Try to wrap it in such a way that there is a gap between the end of the wire and the end of sparkle generator. The video will offer a visual aid if that doesn’t make sense to you.
6. Put the spark generator into the drilled hole in elbow. Grab your spark generator and stick it into that hole that you drilled earlier. If the hole isn’t wide enough do some more drilling before you try to stick the spark plug in there. You don't want to damage the spark generator or the wire.
7. Glue the spark generator with PVC cement. You need to glue it so that it is airtight. This step can’t be skipped or your gun won’t fire.
8. Screw a screw into the side of the chamber. You want to the screw to be sitting in such a way so that it is {{safesubst:#invoke:convert|convert}} away from meeting the prong on the inside. Try to be as exact as you can.
9. Fasten the grill igniter wire. The grill igniter is the piece of equipment with a red dot on top of it in your grill ignition kit. Grab the wire that hangs from the grill igniter and fasten it to this screw on the outside of the chamber. When you click the grill igniter, you should see a tiny spark jump across the prong to the screw. IF you don’t see a spark, check your connections.
   • Don't let your body touch any of the metal parts, your body will take the shock and you won't get a spark. It helps to cover up all of the wiring with electrical tape.

Loading the Gun Safely

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. Use another projectile. 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.
3. Know where your target is and what is behind the target. Never load a potato gun before you have identified a target and are sure that the firing of the potato gun will not result in bodily injury to anyone in front of or behind the intended target.

Firing the Gun

1. Load the gun following all necessary safety precautions. Spud guns are fun, but safety is paramount. Absolutely do not load the gun until you have a safe, intended target far away from anyone.
2. Unscrew the cap and get ready to race the clock. Be prepared to do the next step in 10 seconds or less. If you don’t fire the gun quickly it won’t work. Don’t worry if it takes you a couple tries.
3. Spray deodorant into the chamber for about 5 seconds. Remember that after you do this you should hurry, because half of your time is already up. Screw the cap back on, but absolutely do not cross thread it. This means screwing it on without the threads connecting correctly. Prepare for a kick and push the button on the grill igniter.
   • Try to hold the end of the potato gun low so that it doesn’t kick back against your face accidentally.
4. Watch the potato soar. Congratulations, you've successfully and safely fired a potato gun. Clean your gun with a wet rag before you shoot the next potato from your cannon.

Troubleshooting Your Potato Gun

1. Check to see if the connections are secure. The spark may not be traveling though all of the wires. Check all of the connections.
2. Ensure that you aren’t touching grounded metal. Your body might have been touching something metal when you pulled the trigger, which would neutralize the electrical charge. Stand in an open field.
3. Fire at the appropriate time. If the potato gun didn’t work you probably 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 condense, and you will be left with a sticky deodorant glob in the chamber.
4. Clean your gun. You absolutely have to clean your gun after every shot. It won’t shoot twice in a row. 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.
5. Check your seal. You could have a weak seal around the projectile. Make sure it fits tightly in the barrel.

Tips

• 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.
• Experiment! Instead of dealing with wiring up a grill igniter, 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.
• 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 common sense!

Warnings

• Never fire at anyone or anything. The best place for a potato gun is in a wide, open field without young children around.
• Always check your local laws before firing.
• Do not load a potato gun unless you want to shoot it immediately. There's no sense in loading a gun if you don't want to shoot it immediately; unnecessary loading increases your safety hazards.
• Never shoot your spud gun in extremely cold or hot weather. PVC is generally durable but can get very brittle in extreme weather, posing a safety hazard to the shooter and spectators.
• 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, and can seriously injure an unsuspecting victim.

Related Articles

• Build a Potato Launcher

Sources and Citations

See also

• Make a Marshmallow Gun
• Make a Zip Gun
• Carve Wooden Guns
• Make a Toy Gun
• Make a Pen Gun With a Trigger
• Make a Shoulder Holster
• Make a Water Gun with a Water Bottle
• Make a High Powered Pen Gun
• Make a Glove Gun
• Make a Peg Gun

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• Build a Potato Launcher