Tape or Joint Compound

bigwill

I installed a new shower and the cpvc fitting to the mixer valve is leaking. I used teflon tape on the cpvc threads and tightened twice but still leaks a little. I plan to buy a transition union and replace the cpvc fitting, it is 1/2 inch. Should I use teflon tape or pipe thread compound on the male threads on the transition union? The male threads will screw directly into the mixer valve and I will glue the cpvc supply line into the other end.

Thanks

VIPlumber

A union does not need tape or dope when done properly. Why not just back out your connection to the shower valve, clean it, tape & dope it, and reinsert?

bigwill

I actually need a transition male adapter to screw into the brass female mixer valve, not a union. I tried the cpvc male with teflon tape into the mixer twice but still leaks a little. I have been reading many opinions on which to use on male threads and I cant seem to get a most popular response. Some use only tape, some only dope, some use both on same fitting, some use 1 sort of combination on metal and something different on cpcv. Also if use dope on brass threads, rectorseal 5 or T plus 2?

Thanks

TheEplumber

Using a cpvc male adapter with brass threads? Tape and dope your connections

VIPlumber

Plastic into brass? Be very careful as cross threading is done quite easily.