Are the threads tapered?
3/4" Copper UNION - Use Teflon Tape or Pipe Dope (after sweating the two ends)? Or do you just tighten the nuts. Thanks!
I use a little pipe dope on the threads.
The threads on a union play no part whatever in the sealing function, they are there solely to enable the sealing surfaces
to be pulled tightly together. No dope, no tape, no nuttin'.
Although nothing is required on ANY part of a union joint, I like a little non-setting paste like Great White, both on the threads and very lightly on the mating surfaces, just as a lube and protector. It works for me! Many will suggest a little coating of light oil.
Pipe dope on the two mating faces will compensate for any minor irregularities. On the threads it helps them tighten easier. Putting it on the surfaces BEFORE soldering, makes them "dirty" so the solder does not adhere to the brass, which helps in a vertical installation.
Last edited by hj; 03-01-2012 at 05:58 AM.
Licensed residential and commercial plumber