New valves leaking

[David bedient]

I have installed (sweated) 10 new copper male screw fittings than installed new shut offs 5 leak. I am using Teflon tape 4 turns.. Should I be using paste could the end threads be bad...

Thanks

 

[Reach4]

Try using both pipe dope and PTFE tape. Rectorseal No. 5 is good for metal threads.

A better PTFE tape might help too. The cheap stuff is low density. The higher density stuff will sink in water, once the water bubbles are off. You can use yellow "gas" tape on water no problem.

 

[Sponsor]

 

[Terry]

Sometimes three wraps of tape and then pipe thread sealant (dope) over the tape works well.
Tape should work, but should doesn't always get the job done. Normally I just use thread sealant and it's fine. On shower valves, that's all I use. On larger fittings like 1" I may use both.

 

[hj]

I never use the tape on metal threads, but the important thing is HOW TIGHT is the fitting, not what kind of sealant was used.