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Hand cannon.

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Hand cannon.

Unread postAuthor: warhead052 » Wed May 04, 2011 1:19 pm

Tell me what you think. Also, the projectile is not sealing, so let me know if you can help... The jb weld just simply gets pushed out some how.

Image

Full thing, almost 7 inches long.

Image

Trigger, sorry for the blur.

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Projectile from the side.

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From the front, sorry for the blur again...
And that's all! I hope you like it. Its almost done, once I figure out how to stop the jb weld from coming out of the end... It completely hardens, then it loosens up when pressure is applied.
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Unread postAuthor: jrrdw » Wed May 04, 2011 1:32 pm

JB Weld and most epoxies, bondo and fiber glass resin all shrink some while curing. Looks like you need a adapter to get things down to size. Use the Macro setting on your camera for close up pictures.
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Unread postAuthor: warhead052 » Wed May 04, 2011 1:37 pm

What do you mean an adapter? Its more the jb weld wont harden and stay hardened. It shrinks when I add pressure, but then take away the pressure and its fine.
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Unread postAuthor: PVC Arsenal 17 » Wed May 04, 2011 1:42 pm

You have threads on that plug... why not just cap it? I can't be sure, but from those pictures it seems like you used more resin than hardener... it also don't look cured. Properly mixed and cured JB Weld should have a more grayish color with a slightly glossy surface.

Then try putting a barrel around the sleeve of the quick disconnect and use your epoxy to mold the plug/projectile into a shape suitable for the barrel diameter.

Then you'll have yourself a brutally simple valveless launcher. Just pressurize and pull the barrel back to fire.
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Last edited by PVC Arsenal 17 on Wed May 04, 2011 1:46 pm, edited 1 time in total.

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Unread postAuthor: jrrdw » Wed May 04, 2011 1:46 pm

I was thinking the shrader valve is coming out under pressure. What exactly is coming apart?
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Unread postAuthor: PVC Arsenal 17 » Wed May 04, 2011 1:48 pm

jrrdw wrote:I was thinking the shrader valve is coming out under pressure. What exactly is coming apart?


I think he means the JB Weld used to fill up the plug/projectile. Scoring the inside could also help. Sealing that up should be a very easy task for JB Weld if done right.
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Unread postAuthor: warhead052 » Wed May 04, 2011 2:38 pm

The plug, its coming undone. I figured out why, its because it some how got some other epoxy on it, and it lubed the inner surface, so it hardens then slides out. I fixed it though, and added some extra strength to keep it from sliding out. Currently curing, and should be done by around 7ish central time zone.
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Unread postAuthor: jrrdw » Wed May 04, 2011 3:05 pm

Yea that's one thing about JB Weld, the metal has to be clean.
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Unread postAuthor: warhead052 » Wed May 04, 2011 3:08 pm

Yeah... I fixed it though I hope. If not, when I go and buy some more parts for a diff project, I will get some new plugs and maybe caps.
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Unread postAuthor: jrrdw » Wed May 04, 2011 3:18 pm

The brass fitting section at your local hardware store is a must see. At the True Value near me there are 3 bins on tracks approx 5' tall x 3' wide with about 90 draws. Brass fittings heaven!
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Unread postAuthor: warhead052 » Wed May 04, 2011 3:21 pm

Nice. I also solved my problem with the freon tank. Got a 1/8th to 1/4th reducer, and it put the schrader that you see screwed in up in the pictures on it, and it pressurized to 5-10 psi. My bike tire gauge said 20, but the other gauge I put on instead of the schrader said 5 - 10.
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Unread postAuthor: PVC Arsenal 17 » Wed May 04, 2011 4:05 pm

Post some videos up when you get a chance. It's kind of interesting to see these things fire (at least in my opinion). This type of launcher has a lot of potential.
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Unread postAuthor: jackssmirkingrevenge » Wed May 04, 2011 4:07 pm

strip the rubber off the schrader and it will stick better: http://www.spudfiles.com/forums/viewtop ... html#80833
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Unread postAuthor: warhead052 » Wed May 04, 2011 7:26 pm

Jack, the rubber has been stripped, everything has. I had to slightly increase the inner diameter of the plug for the schrader to fit, but yeah, its fine and perfectly sealed. Its just the other end, the projectile, thats not sealing when I plug it in.

PVC, this thing has a distance of...... NOT EVEN 1 METER! YAY!!!! :evil:
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Unread postAuthor: warhead052 » Wed May 04, 2011 8:21 pm

Argh, stupid plug keeps sliding out and releasing pressure! :evil: Is there any way to solve it? It holds up to 2 shots, then slides out. Is there ANY way to stop that? And make it hold up to at least 100 shots?
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