Epoxy the leak, or just screw the blowgun in tighter with more teflon tape (you did use teflon, right?)

Lubing the valve really isn't necessary. My valve has worked fine without it for two years now. However, you may still want to open up the valve from time to time to check for debris that may be ...

You are correct.

Any time, any time. Always like to help a "noob" out.

BTW, take some pics of your cannon!

Hmmm... I had the same problem on my first cannon. Did you epoxy it or just pop it in? Is your hole perfectly round?

Just drill a hole, and pop it in. Add some epoxy if you so desire.

Yes sir, you are safe for pressurization. Though the threaded types of schraders (those with threads on the bottom end for screwing into the air chamber) are generally deemed safer and easier to use, I assure you that the type you have is perfectly safe for use. (I have used one up to about 125 PSI ...

Your hardwork has definitely paid off. The gun looks great and I'm sure it performs great as well. I always like a good military-themed gun.

Keep buildin',
Praetorian

Now your just splitting hairs...

Aside from that, yes everything is there, and yes my point has been proven.

If you use your brain, everything is there. Even the 4 inch male adapter, which can be found on the page he listed as the "female adapter page".

EVERYTHING IS THERE!

Edit: Modder fixed ...

His 2nd to last one is wrong, but the rest are solid. In fact, he has pointed all the parts you need. Just proves my point about McMaster having everything if you look hard enough.

Heres my tip: If you ever want to get the cannon done, follow those links and buy from McMaster. "Expensive" though ...

Remarkably, the air leaks fast enough to seal the valve. Any sprinkler valve is proof of this.

I think very small diameter plastic tubing might work, although it may still be too much. Try it and see, as the rest of your plan looks solid.

A neoprene disk will work perfect as the diaphragm ...

Heres the solution to your problem:

Most sprinkler valves use only a tiny equalizer hole to release air into the top part of the valve to close the diaphragm. When the valve opens, only a tiny bit of air can be wasted because of the minute size of the hole. You plan on using copper pipe to equalize ...

Spudthug, here is my suggestion:

I would hold off on the fittings. Purchase them from McMaster, which will tell you all the stats about what you are buying. I would rather wait a few days than feel uncertain about the pipe I just bought. I've bought numerous times from Mcmaster, and beleive me, its ...

Yeah... except that the guy already has the sprinkler valve and has modified it.

Good luck with the rest of the cannon pat123.

Depends on the one you choose. That means, choose one with female threads on each side, so you can fit a male adapter into it. Its truly not that hard.

Thanks Gepard, I just wanted to get an idea of what the testing conditions were like.

If anybody else knows more, fill me in.

Thanks,
Praetorian