SpudFiles

A year or two ago I had made a (very) simple pneumatic piston valve cannon, you can see it by googling "spudzooka" My problem is that whenever I try to pump it up, the air just mostly escapes through the barrel. There could be many things wrong: diaphragm dried out, space between back cap and barrel to large, diaphragm misshapen etc. I think the problem is that my potato is pushed in too far, and is blocking proper movement of the diaphragm. Is there anyway I can get it out without just sawing apart my gun? (in frustration that there were many leaks, EVERY connection is both glued and heavy-duty caulked over, the only way to access the inside is through the barrel)

Coil a large corkscrew with some wire, sharpen one end and hook it into the potato. It works for muzzle loaders and cannons.

How would I hook it into the potato without pushing it farther in? I don't want in actually fully inside my chamber,

If you twist it as you hook the potato, it won't push much further in, once it's in a full turn, then pull it out slowly.

Alright thanks for the help

this happened to me in my mini coaxial, its soo frustrating, i shook it for like hours to get it out. For future projects you should use a threaded fitting in the back so its easier to clear clogs.

I did use a threaded fitting... but in a fit of frustration I glued it closed cause there were leaks everywhere... not the smartest thing I've ever done.

When is the last time you actually fired this thing? If its a few years old maybe its time to make a new one. It sounds like its pretty much FUBAR anyways!!

I've never gotten it to fire when I originally made it I didn't have a good compressor (it was broken and would only pump a little before slowing then stopping) so I kind of just left it for a while, recently I have gotten back in to making DIY zombie stuff and figured I would try to fix it, (that's when I discovered the potato was too far down)

What does FUBAR stand for?

FUBAR stands for fu*ked up beyond all recognition lol. The potato is not your problem, the piston probably is. If everything is not near perfect, like the piston size, pilot, etc. it will not work. Does the piston even seal properly???

I would recommend building anew anyway as the "SpudZooka" plans are several years old and still incorporate DWV and even sewer fittings, which are dangerous, especially at the back of a piston valve.

Take a look around here for some good plans. Mr.Crowley has some pretty good instructions for a barrel sealing pneumatic here.

Try to plug up the barrel and fill the gun, that might push the potato a out little. Then refill and shoot it out

He cant shoot it out because the valve never worked in the first place!!!!

Has the spud been in there a while?

Fill the barrel with water (and, if possible, the chamber and valve as well) and lit it sit overnight. Go in through the muzzle with a something long and thin and mash the spud.

Lol yes... The spud has been in for years xD I might just ditch the whole thing and make a new one