[darkmorford]

I just exchanged my empty CO2 cylinder for a full one, and a leak has popped up where there wasn't one before. I disconnected my keg system at the regulator to give me the fewest variables possible—just the tank and regulator—and it still won't hold pressure. After subjecting the thing to the bathtub bubble test, it looks like the leak is at the connection between the cylinder and regulator.

I've tried everything I can think of: two different washers (one fiber, one nylon), fresh teflon tape on the threads, even throwing on extra layers of tape to get a tighter seal. I'm still losing pressure at the tank connection, though it's very slow at this point. What else can I do to stop this leak? (Or do I just assume the tank's threads are shot and deal with the loss?)

[bo]

The seal between the tank and the regulator has nothing to do with the threads. It's all in the seal. Looks for a nick in either mating surface. If it's the tank take it back to the filler or swap it with a different one at a welding shop.

[darkmorford]

Should I take all the teflon tape off of the connection, then? There was some tape on the tank when I got it, so I assumed it was necessary.

[euge]

The seal between the tank and the regulator has nothing to do with the threads. It's all in the seal. Looks for a nick in either mating surface. If it's the tank take it back to the filler or swap it with a different one at a welding shop.

Yeah that's probably the best course of action. And why I don't swap my nice tank.

Should I take all the teflon tape off of the connection, then? There was some tape on the tank when I got it, so I assumed it was necessary.

I don't use teflon on those threads. You can if you want I guess. They're both brass so no corrosion risks. Teflon isn't used to protect a seal from leaking. It's there to prevent damage to the threads.