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Trouble with Teflon. Use Pipe Joint Conpound?

13 years ago

I am having trouble with a brass 1" PEX to male thread adapter. I am attaching it to a copper female joint, but have done this 3 times now and it keeps leaking. I use Teflon on the treads. I tried doing from 3 rounds of Teflon around the tape up to 10 (in the direction of the thread), same thing, slow leak about 1 drop per minute. Im probably using 40-50 lb-ft of torque (as much as I can apply in crawlspace without pipe extensions, IÂm weary of applying more torque on a copper fitting anyway). It is a PITA because for each attempt I have to undo the PEX copper crimp, cut the PEX pipe a little shorter, recrimp and then crawl in and out of the crawlspace to test it.

Now, I am using Teflon tape in a red container with a white cover. I thought that is the "triple density" one. However after the third failure I compared it with some yellow (gas, presumably double density) tape and the yellow one seems thicker. Also the color of the tape itself is white not pink as I saw described in a previous post. Am I using the right tape?

In any case, IÂm thinking of using pipe dope. This is a water supply line (main). Should I use Rector Seal No 5?

The threads look ok, but assuming the cause of the leak is some minor thread problem, will the pipe dope do a better job than the Teflon?

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