Any trick to keeping compression fittings from weeping?
I'm replacing the water supply-line valves in my bathroom (hot and cold to the basin, cold to the toilet). The old ones were 38 years old and I wanted to upgrade to the new 1/4 turn ballcock design. This is part of a total bath remodel.
The supply lines are 1/2 OD copper pipe and the valves attach to the copper pipes with a compression fitting (brass sleeve between the valve body and the compression nut).
Seemed straightforward, after removing the old valves I made sure the supply lines were not out of round and were not galled. The ends of the pipes were cut at 90 degrees as they should have been. I used fine steel wool to remove any surface corrosion and to leave a smooth surface.
Wiped everything down well, installed the valves hand-tight (being careful to not over-tighten) and turned the water back on.
Two out of the three valves weeped water around the compression fitting, I could feel moisture where the pipe entered the compression nut. Not enough to drip, but not a perfect seal. Tightened a little more by hand, rechecked, and they were still weeping.
I finally removed all the valves, put on new compression sleeves, but this time I smeared a thin coating of pipe thread compound (Harvey's TFE paste) around the pipe before I put the compression sleeves on. Tightened everything hand-tight as before, turned the water on, and no more weeping. Dry as a bone.
Question: is it common for new compression fittings on old pipes to weep? My solution worked but is there something else I should have done instead What would a "regular" plumber have done? I might need to go through this all again in another bath.
Thanks for your help.
- Spellcheck