Here is what I'm trying to do:

I'm inserting a 3/4" galvanized steel plug into a 3/4" stainless steel pipe connector that is welded to a steel plate covering a pressurized water tank that has 60 psi. My objective is to insure the steel plug does not leak but unfortunately it is. I've tried using teflon tape on the plug threads but it leaked. I also tried using PFTE pipe dope and it leaked.

One thing I seemed to notice is that if I tried tightening the plug more, the leak seemed worse. Did I tighten it too much?

Would the leaking stop if I use both together? Or should I use something else to seal the threads? BTW, the pipe connector and plug are new.

Would appreciate suggestions.

Thank you

 

Either should have worked, 60psi is not excessive. remove everything, clean and use both.

Are you sure you are using compatible threaded pieces NPT vs straight threads, there is a bid difference!

 

What sealing method does your plug use? Does it have a gasket/washer, O ring or is it a tapered thread like NPT?

If it uses a washer or O ring check the sealing surfaces for scratches & nicks. Your gasket or O ring must also be in good condition.

If it's a NPT thread use a pipe dope and tighten the snot out of it. If it still leaks then I'd try another plug. Tapered threads rely on a precise metal to metal fit in the threads and there are always manufacturing tolerances that can sometimes make it more difficult to get a good seal.

 

I'm sure both are 3/4" NPT

 

I use Teflon tape with a generous coating of RectorSeal5 swirled around over the tape , and then as Pilot Dane says - tighten the snot out of it.

I used to dread threaded connections and had many leaks – but after doing the above I haven’t had any leaks at all.

(At first I thought pipe dope over Teflon tape was nutty – but turns out many plumbers actually recommend that. It seems to work very well!)

 

Use both. That is what I see plumbers and fire sprinkler fitters do.