I just ripped out all the water lines from my kitchen to the basement connection. They were a plastic disaster and I replaced it all with copper. All the soldered connections were fine. However, due to problems getting the water supply to completely shut off I elected to use threaded ball valves with ferrule fittings on one side to make the connection. The ferrule fittings work great but the tapered threaded connections leak. I installed 3 of these threaded valves and all 3 of them leaked. I used an abundance of Teflon tape. The valve I got to seal properly required about 80 lbs of torque and I bottomed out the fitting. There was no more thread to turn.
I’ve since found that you can buy ball valves with ferrule fittings on both ends which would have been swell (3 times the price though). So I’m wondering, is Teflon tape my friend or enemy. Can I sweat threaded joints together or glue them? I thought about gorilla glue since it activates with water. I’ve got the last 2 valves down to a leak that is 1 or 2 drops per day. I’m a little reluctant to put the torque required to seal it because I’m worried about a wrench slipping off and folding all this pretty copper into a spiral. I don’t ever remember having this much trouble with a tappered threaded connection.
If your fittings were threaded poorly they may need epoxy to seal them.
how far can you thread them together by hand dry? if they go over 1/2 way by hand you have a problem.
PTFE tape is not the problem unless you used an excessive amount. 3/4" tef tape on 1/2"NPT takes three wraps. Threads must be clean and started properly.
I’m wondering if you might have mismatched fittings, maybe NPT and NPTF.Things look the same but aren’t, roots and crests differ ( shouldn’t “bottom out” ).
Or, possible foreign made substandard specs. China and India contribute to this.
I would pull it all apart and re-do. Ferruled unions can be had if you don’t need the shut-off.
Gluing and sweating threads is vomitory DIY well deserving contractor scorn, and affords opportunities to do it again and again.
I didn’t know there were 2 types of tapers. There are no markings on either parts. I still have the package the tapered male sweated pieces came in and there’s no indication. That would certainly explain the poor fit. Both parts were made in the US.
I didn’t use 3/4" tape, more like 1/2". I did build up about 3 layers of it on the 2nd attempt.