How to Build Spud Air Guns

A spud gun can launch a potato hundreds of feet.

Compressed air has many uses. It inflates tires, powers shop tools, and it sprays equipment clean. When the work day is done, however, you can play with compressed air. A tank full of it carries a lot of kinetic energy; when you release that energy, it can give an object a mighty kick. This is the principle behind the spud gun -- also called the spudzooka, tater taser, or spudchucker -- which uses a tank full of air to fire a potato from the end of a pipe. Building one is easy with basic plumbing parts.

Things You'll Need

• 48-inch piece of 2-inch diameter PVC pipe
• 2 2-inch PVC pipe elbows
• 2-inch PVC pipe valve
• 4-inch to 2-inch pipe reducer coupling
• 18 inches piece of 4-inch PVC pipe
• 3 2-inch pieces of 2-inch diameter PVC pipe
• 4-inch PVC pipe cap
• Schrader valve
• Brush
• Drill
• Hacksaw
• Wrench
• PVC primer
• PVC cement

Instructions

1. Measure the width of the thick end of the Schrader valve (a small threaded metal piece that allows you to attach a pump) and drill a hole of that width through the side of the 18-inch piece of 4-inch diameter pipe.

2. Wrap the thick end of the Schrader valve in 4 or 5 layers of teflon tape, then twist the valve into the hole you drilled, using a wrench. The teflon tape will give it an airtight seal.

3. Attach a cap to one end of the 4-inch pipe with the valve in it. To hold the cap in place, use a brush to cover the pipe end with PVC primer and PVC cement before fitting the cap onto it.

4. Attach a 4-inch to 2-inch reducer coupling to the other end of the 4-inch pipe with primer and cement.

5. Attach a 2-inch piece of 2-inch PVC to the end of the reducer, then fit a 2-inch PVC valve over the other end of the 2-inch long piece. Join them with PVC primer and cement.

6. Cement another 2-inch long section of 2-inch PVC to the other side of the valve.

7. Attach a 90-degree 2-inch pipe elbow, another 2-inch piece of 2-inch PVC, and a second 90-degree elbow to the free end of the pipe. This will make a 180 degree turn in the pipe.

8. Prime and cement one end of the 48-inch piece of 2-inch PVC and fit it into the open end of the second pipe elbow. This will be your spud gun's barrel.

9. Set the gun aside for 24 hours to allow all the cement to dry.

10. Test your spud gun. Shove a potato into the barrel as far down as it can go. Close the PVC pipe valve, then use a bike pump or compressor attached to the Schrader valve to pump up the tank to between 60 and 100 pounds per square inch. Carefully point the barrel away from people and buildings, then open the valve to fire the potato.

Tips & Warnings

• Spud guns are not legal in all jurisdictions. Always check with local law enforcement before making and firing one.

• Never point a spud gun at anyone or anything. A potato travelling at high speed can injure or kill someone.

References

• Spud Gun Depot: How to Make a Pneumatic Potato Gun