Stop a leak

[PVCpneumatic]

Hey Guys and Gals, How can I make a Male to female joint air tight without gluing it together? This is for my air cylinder to ball valve and ball valve to barrel connections. As it is my first spud gun, I am rather lost. Help?!
cheers.

[jackssmirkingrevenge]

Er... thread tape?

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... or are you not taking about threaded fittings?

[PeteS]

Er... thread tape?

Or maybe PFTE paste. I use tape for most smaller stuff but in bigger sized stuff I like the paste that comes in a tube. Again assuming you are talking threaded connections.

[PVCpneumatic]

Cheers guys. That worked a treat. And now I can get the system up to ten PSI before my glued joints start leaking. Again this is my first cannon, so im just following a simple design. I am thinking of using a hard setting resin around each glued joint and the pump valve. Also... Rubber to PVC... Is there an easy way to get an air tight seal?

[PeteS]

For solvent welded pvc joints that leak...
Pressurize the cannon and submerge it to find the leaks. Once you know where they are you can pull a vacuum on the gun, a shop vac is good enough, apply primer and pvc glue to the leaking spots. Allow it to draw in some primer and glue and then turn off the vacuum and allow it to dry.

Next time use more care in priming and gluing to avoid the leaks in the first place. Oh and when solvent welding new joints 1/4 turn while putting the joint together helps.

For rubber to pvc, super glue (cyanoacrilate) works well for gluing rubber faces on pvc pistons. Anything else that I tried, short of a bolt, failed quickly.

[PVCpneumatic]

Cheers PeteS. Hopefully this will work for all future models that I make. I know where all the leaks are, but the contact glue that I used to attach the bike pump valve starts to bubble when pressure exceeds ten psi. So superglue and a vacuum should be all I need? Wonderful. Your help has been much appreciated.