Compression 1/4 turn shutoff drip stopped itself - should I still tighten it?

[teecee]

I installed a couple of quarter turn compression shutoff valves. Hot side was ok. The cold side had a very small drip - like 1 drip every hour and then the next day it slowed further. But I do feel very small leak when I touch it.

I removed it and installed it again with a new valve. Same result. I used dope on both the ferule and the threads.

Should I still tighten it further or leave it alone?

 

[Reach4]

But I do feel very small leak when I touch it.

Does that mean the leak did not stop? How about giving the nut another 1/8 turn, using two wrenches.

 

[Sponsor]

 

[teecee]

It is not 100% leak free. After every few hours when I touch it i feel a very small drop. I thought I tried my best to tighten it as much as I can but I will try again for another 1/8 turn.

Should the threads completely screw in?

 

[teecee]

Does that mean the leak did not stop? How about giving the nut another 1/8 turn, using two wrenches.

It is not 100% leak free. After every few hours when I touch it i feel a very small drop. I thought I tried my best to tighten it as much as I can but I will try again for another 1/8 turn.

Should the threads completely screw in?

 

[Taylorjm]

That’s very common and is nothing to worry about. Tightening it more can actually cause worse issues so it’s a delicate balance. If it stops then you’re fine. If not then give it just a little bit more. I just installed a toilet quarter turn valve at my place that had a slight drip. I put a container under it and by the next day it was fine. That’s not how I’m used to doing things but my dad was a pipefitter for 40+ years and has done thousands of jobs with instruments that use compression fittings and he told me leave it alone and it will stop. I laughed and said sure. I hate it when I’m wrong.

 

[Reach4]

It is not 100% leak free. After every few hours when I touch it i feel a very small drop. I thought I tried my best to tighten it as much as I can but I will try again for another 1/8 turn.

I think I cannot over-tighten with 6 inch long wrenches, but somebody else might be able to do so. Also, stop valves are often in an awkward position that makes tightening harder.

Longer wrenches make for much easier turning.

 

[Taylorjm]

I think I cannot over-tighten with 6 inch long wrenches, but somebody else might be able to do so. Also, stop valves are often in an awkward position that makes tightening harder.

Longer wrenches make for much easier turning.

You can defiantly over tighten a compression fitting. I’ve done it with 1/4, 3/8 and 1/2” copper. Once you over tighten it you are screwed because the ferrel is crushed and won’t seal again. Especially with 1/4” copper for refrigerator water supplies. They are very easy to overtighten.