How to Build a Potato Gun

PVC pipes form the potato gun body.

Potato guns, made famous by resourceful teens and their fathers during potato festivals, show up regularly at science fairs. However, a potato gun launches a potato with force for a few hundred yards and as such, an adult must supervise the construction and operation. You can learn a lot about chemistry and combustion with a potato gun but safety comes first. Read on to learn how to build a potato gun.

Things You'll Need

• PVC pipes (in various lengths)
• PVC connectors and end cap
• PVC glue
• Grill igniter
• Hack saw
• Drill with 1/8-inch bit
• Potatoes
• Hair spray (aerosol)

Instructions

1. Cut a piece of 3-inch PVC pipe into a 12-inch long section. This will serve as the combustion chamber.

2. Drill two holes opposite each other in the middle of the pipe and insert the end wires from the grill igniter, one into each hole. Look into the pipe as you position the wires until they are about ½ inch apart. Glue the wires into the holes, taking care to seal the holes completely.

3. Fit a 3-inch PVC end cap with a screw-on mechanism on one end of the pipe. To do this, you will clean both the end of the pipe and the inside of the screw portion of the end cap before applying an even coating of PVC glue to a 1-inch segment on both. Quickly fit the pieces together and push the cap on tightly.

4. Use the same method to apply a reducing PVC connector to the other end of the pipe. Choose a connector that reduces the opening from 3-inches to 1 ½-inches in diameter. Once PVC glue is applied, move quickly, since it will adhere very quickly.

5. 

   Add a 3-foot piece of 1 ½-inch PVC pipe inside the connector, gluing it securely. It’s important to make sure your joints are secure or your potato gun could fall apart when pressurized.

6. Discharge your potato gun in an empty area, such as a field where no houses are around. A potato will easily break a window or harm a person. Some communities ban potato guns within the city limits so check with your local law enforcement agency before shooting yours.

7. Pack the narrow chamber with a small potato and push it in with a rod or broomstick.

8. Remove the end cap and spray hair spray into the combustion chamber. Quickly replace the cap.

9. Aim your potato gun in a safe direction and hit the igniter. Hold onto the gun firmly as it will kick when the potato launches.

Tips & Warnings

• Like fireworks and model rockets, potato guns can be fun and educational but also very dangerous. Don’t shoot one unless your parents are supervising the activity.

• Be prepared to lose your potato gun if you act irresponsibly. Although they are legal in most areas, the police will not react favorably should you discharge it in a dangerous manner. They could confiscate your potato gun and you will be liable for any damages the launched potato causes.