If you are the kind of person who needs to shoot a little wad of potato at someone moving in slow motion, this may be the gun for you. It uses a twist of tubing, a Zippo, and some water to create the ultimate in potato-attack technology.
The full DIY appears on Instuctables, but this thing is pretty basic.
Of note: some very dire safety warnings that I don’t want you people to ignore:
I also want to start by re-iterating his safety warnings as this device has risks related to fire, steam, pressure, metal-work, and projectiles. I recommend wearing eye protection during all steps and using common sense. I accept no liability for any risk in the manufacture or use of this device. Do not attempt to use power tools if you are not familiar with them and I don’t recommend anyone under the age of 18 attempt to manufacture this device without competent adult supervision. Don’t touch the barrel for a few minutes after it has been fired as it
becomes extremely hot. Also, the soot will stain clothes/skin. Be careful with this thing guys.
Soot: the silent soiler.