Compression ring not compressing

[Hnvdt knight]

Hello! I’m new to plumbing so please forgive me if all the terms aren’t right. I’m replacing a leaky right angle stop valve with compression fitting. Removed the old valve, compression ring, and bolt, and put the new bolt, then ring, then valve on. Hand tightened with the valve pushed all the way back on the pipe. Tightened slightly further with a wrench. At that point, the whole valve/ring/bolt was spinning entirely unattached to the pipe and could easily be pulled off. Gave up and tightened as much as I possibly could using a pipe wrench and channel lock pliers (I know this is frowned upon). After, the valve could still be rotated around the pipe but took more effort. No surprise lots of leaking when I did a test run. Removed the whole setup and saw that the compression ring was still unattached around the pipe and easy to remove. Separating the valve from the nut was very challenging and required several tries with the pliers. All components have been compared to the just removed set and are identical. Any insight why cranking as hard as I can left the ring detached when in theory it should be severely compressed/malformed?

 

[Reach4]

It takes two wrenches to tighten a compression valve, or a wrench and a locking pliers. And it takes more torque than people usually think. I don't think you can crush the copper tube with 6 inch wrenches.

So get two good-fitting wrenches. Lube the olive/ferule/ring with some silicone grease or pipe dope, and also lube the threads. Then tighten using both wrenches, and don't worry about crushing unless you are unusually strong. The lube will reduce the amount of force you need to apply, but unless you have 10 inch wrenches, I think you cannot crush the pipe/tube. I am not a pro.

 

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[Jadnashua]

The threads on some valves (usually made in China) tend to be made with what may have been dull tools, so the nut can bind some when trying to tighten it up...that's what a drop of oil on the threads can help with. Otherwise, the nut may 'skip' a little bit as it binds, then releases, rather than being a smooth tightening. Unless you're really strong, a 6" wrench may not be big enough to apply the needed torque to create a good seal.

Once it's tight enough, you should not be able to turn the valve on the pipe.

If the pipe surface is scored, or dented, it may be tough to get a compression fitting to seal properly.

 

[Fitter30]

When a compression ring seals it has to be tight enough to deforms the pipe so the ring doesn't come off. 1/2" compression would take at least 10" -12" adjustable wrenches .