Sweet thanks, that's a good idea. Now my only question is; do I want to lacquer the cannon now? See, the problem is it's not really "complete", it's just functional. I had planned to make it a lot more complex, but ran out of time during the summer. Cause I get the feeling that once I clear-coat it,...

Where would one buy this 2-part lacquer? Any recommended brands?

That's a pretty good idea, but it might be a while before I manage to implement it; school is starting in a week and damned if that doesn't tend to consume my time.

I really owe you an apology, I don't think I noticed your original suggestion. You must've been sitting there thinking I'd totally cold-shouldered your input. So really, sorry about that.

Shit, now I've got epoxy all over my piston.

that sounds dirty.

Well oh my, don't I look like a fool. It *was* leaking around the copper sealing face and into the barrel. And yeah, the reason i didn't use some water earlier is because I had just finished polishing it to be all nice and sexy, and fucking moisture in the bane of my existence. Anyone know a good wa...

It had a +.01 tolerance and was pushed in with a hydraulic press. I think it's fully sealed.

I couldn't get the aluminum backing off of the threaded rod because of the JB weld, so I applied epoxy at the red arrows: http://imgur.com/79TFG.png The nut-side I "snowplowed" into the washer, and the side on the aluminum backing I just applied epoxy. Again, I could not easily rotate the aluminum a...

There should be atleast some epoxy on all the threads in that area.

So I applied epoxy to the nut, let it set, and brought the gun up to bike-pump pressure. Still leaks /: Mind you, I think this did help a bit, but it didn't solve the problem. I hate to think the valve-side sealing face might be slightly out of alignment, or for that matter any part of the valve. An...

Right, that makes more sense. I guess both would work, but that way is prettier. Thanks

I'll give it a shot today, we'll see how it goes.

Thanks for the input!

So just to clarify, you're suggesting putting a glob here, covering the bolt and contacting the washer?

Guh, that's gonna suck if I ever want/need to change part of the piston.

The rubber of the sealing face is already a very tight fit around the threaded rod, to the point where you actually have to "screw" the rubber down the rod.

I figure the next thing I'll do is put on a slightly bigger washer and slap some Loctite on the threads.

So I sandwiched some JB-Weld between the aluminum backing and the rubber sealing face, let it set over night. Unfortunately the leak is still present, although it seems slightly diminished relative to the pressure I got it to. I ran out of CO2 and had to switch to a bike pump, so my max was at about...

Oh my. It appears this is a double post. When I originally posted, I got an error, and upon inspection didn't see that a post was created. Apparently I did not inspect close enough.

The actual thread is here.