Everybody wants a potato cannon. Especially #1 & #2 sons.
However, it's not entirely wise to let small people play with explosives or high-pressure gases. At least, not without me there to, er, supervise.
Enter the Pneumatic Potato Pistol - pocket-sized ballistic mayhem.
Step 1: Tools and Materials.
- Hot glue (or epoxy)
- Cutting and grinding tools - either a hacksaw, file and sandpaper, or a rotary tool with appropriate bits.
- Safety gear - you will need goggles if you're using a rotary tool on the pen, be careful around hot-glue, and read the safety instructions on the packet if you are using epoxy. For the safety equipment needed when you use it, check the video in step four.
- A large syringe. I acquired mine from school, but you can sometimes get them from pharmacists - ask for large oral syringes.
- An old biro or similar stiff narrow tube.
Step 2: The Barrel
Cut off about 6cm (about two and a half of your American Inches) of the blunt end of the pen.
Near the closed end of the pen, drill a hole large enough to take the syringe nozzle. Note that the syringe I am using has a wider diameter near the base of the nozzle, and that is the diameter I am working to.
If you are planning to use the pistol to fire actual potato, grind the open end of the pen to a slightly chamfered edge. It doesn't need to be razor sharp, it just makes it easier to push into your spud.
Step 3: Construction.
The nozzle of your syringe (do I mean nozzle? I bet there's a medical word, but you know what I mean) is probably longer than the internal diameter of your pen. Trim it down to give plenty of clearance to allow air through.
Lay the barrel across the top of the syringe, with the stump of the nozzle in the hole you drilled. Hot-glue (or epoxy) the barrel in place, making sure there is an air-tight seal all round the point where the nozzle enters the barrel.
Let the glue cool fully before using the gun. This can take longer than you think, especially if your layers are thick.
Step 4: Firing
Insert your ammunition - either a paper pellet, or a lump of spud. To load with potato, press the barrel into the potato and lever it out. That will leave a spud "bullet" sitting in the barrel mouth. You could ram it further down the barrel with a matchstick, but there's really no benefit.
Hold the pistol in your favoured fist, with the barrel sticking out past your fingers, aim, and smack the plunger with your other hand.
Like the video: