My first real pneumatic...

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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suburban spudgunner
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Thu Jan 08, 2009 11:17 pm

I built this one a few years ago and haven't really had the time (or money) to build a better one yet. Figured I'd upload it just for the hell of it.

The whole thing is constructed of galvanized steel pipe, with a 3/4 inch chamber connected to a 1/2 inch barrel. I used a 250 psi rated schrader valve for air intake, and a 1/2 inch brass ball valve (currently seeking to improve this) for release; it's rigged like an actual trigger pull, and I only have to move my fingers about an inch to fire. It's accurate enough for my standards, and I'm trying to get a laser sight (along with some other useless cool stuff) for it.

Kinda had to stick to small-scale pneumatics with this one, since I live in a small suburban area with plenty of anal-retentive neighbors.

A horribly made video can be located here:
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My humble little spud gun...
My humble little spud gun...
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The definition of insanity is doing the same thing over and over again and expecting different results.
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MrCrowley
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Thu Jan 08, 2009 11:30 pm

Not bad, though putting a laser on it will be pointless because you're using a ball valve. When you trigger a ball valve, it will throw of your aim when you try and open the valve really quickly.
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Cosmic Muffin
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Thu Jan 08, 2009 11:30 pm

looks good :wink:
try to spring load the ball valve or replace it with a solenoid valve, will make it much more powerfull.
and why dont you remove one of the chambers so it looks more like a rifle-then you could add some "useless cool stuff" on top the barrel like a scope
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frankrede
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Fri Jan 09, 2009 7:50 am

Looks like this will last 50+ years ha, nice work, You should spring load that ball valve for better performance!
Current project: Afghanistan deployment
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JDP12
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Fri Jan 09, 2009 8:32 am

nice first gun, I say put a spring loaded ball valve on there. it will open faster and with less effort.

EDIT: Dang frank beat me. I didn't see his post cuz i had this thread open for an hour and never refreshed it.
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suburban spudgunner
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Fri Jan 09, 2009 8:55 pm

Thanks for the feedback.

Mr. Crowley: Actually, the ball valve works surprisingly smoothly on this; I used to have a laser on it (which stopped working), and the shot would hit only about an inch away from where I was aiming.

Cosmic Muffin: Removing part of the chamber would take decrease the volume of air the gun could hold, while also decreasing its accuracy: the shape of the chamber allows me to rest the top half on my shoulder, while the bottom half provides support underneath (fitting nicely in my armpit), which gives it a lot of stability to compensate for the force needed to open the ball valve.
I think I will try to get a spring loaded ball valve: I'm assuming it's probably cheaper than a solenoid?

Thanks again: glad you're all being constructive.
The definition of insanity is doing the same thing over and over again and expecting different results.
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Sticky_Tape
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Fri Jan 09, 2009 9:37 pm

There are fake pneumatics? Were you good at making them? Jk I like your gun I made a bver a while ago but discovered.. Piston valves are more fun hintity hint hint.
You can tell how awesome a cannon is by the pressure used.
http://www.spudfiles.com/forums/high-pr ... 12803.html
xnt rnm ne z ahtbg
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Cosmic Muffin
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Fri Jan 09, 2009 9:43 pm

oh right, you could always add a larger chamber but if you have something to rest on your shoulder then that seems like the better alternative.
and yep it would be alot cheaper, springs you can find everywhere but valves are about 20 - 40 bucks Australian, then you have to mod the valve ( + 10 bucks for hose barbs, hose and blowgun) and its alot easier to add one spring
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suburban spudgunner
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Sat Jan 10, 2009 12:24 am

I made a crappy one before this with a few of my friends, before I knew anything about pneumatics or engineering. As a result, my first gun had no real practicality: it was unstable, hard to trigger, constantly leaking, etc.
The barrel was only about 2 feet long (1/2 inch), with a chamber of the same length (3/4 inch) curving underneath, which was both unnecessarily large and awkward for that particular gun.

I meant this was the first one that I actually planned out for accuracy and power, before going and spending all of my money on plumbing parts to build it. What I have now is the product of a couple years of tinkering.
The definition of insanity is doing the same thing over and over again and expecting different results.
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