Stop Valve Compression "confusion"

[bjferri]

I know I'm making this "MUCH" harder than it is but I again don't understand how much pressure to apply when tightening this fitting. I tested with a piece if 1/2" copper...put the nut on, then ferrule, bottomed the valve out, slid the ferrule close to the valve, then hand tightened the nut, then took a wrench and maybe turned it half turn with a lot of pressure. I even tried to pull valve off pipe - couldn't (I have a fear of water pressure blowing it off) then I unscrewed nut to remove valve and the ferrule slide right off...didn't even looked scratched? I'm baffled!!

[jadnashua]

If it doesn't turn and doesn't leak, it should be fine.

[Gary Swart]

Do the real connection as you described doing the test, but this time put a few drops of light oil, 3 in 1, sewing machine, or similar on the threads. Don't use pipe dope or tape. If it leaks, tighten it some more.

[gear junkie]

Do the real connection as you described doing the test, but this time put a few drops of light oil, 3 in 1, sewing machine, or similar on the threads. Don't use pipe dope or tape. If it leaks, tighten it some more.

You're recommending to put a petroleum product in the potable water supply? WTF? Use pipe dope or tef tape. The compression fitting depends on deforming to make the seal. You should not need to slip the compression ring off. What size wrenches were you using? The amount of torque applied is relative to the person. What seemed like a lot to you might not be enough. Try upsizing your wrenches. You won't hurt the pipe.

[Redwood]

I use a dab of plumbers grease when I install compression fittings.

[bjferri]

Thanks for the comments. I'm sure it's all about the torque as I will soon find out. I'll nix the tef. tape/pipe dope/ etc. and do this dry but apply more torque.

Thanks again...

[Redwood]

You're missing the point! Use Grease! It allows the threads to be lubricated so you get the right torque!

[Gary Swart]

Plumbers grease will certainly be OK. But, yes a few drops of light oil will can also help. Light oil is not poison and the minute amount you would actually get in the water supply would be so diluted by the time it got to a faucet, you would never taste it. Remember, it goes on the threads not inside the pipe.

[SteveW]

I agree with Gary and Redwood - this is all about lubing the threads with something that won't get in the way of the nut adequately deforming the ferrule. Teflon tape, and even some thick pipe dopes, can interfere with the nut tightening enough to do the job.

Terry posted info from one of the compression stop manufacturers to use a couple drops of oil on the threads some time ago.

[Mikey]

If it makes you feel better, use castor oil ...

[gear junkie]

Plumbers grease will certainly be OK. But, yes a few drops of light oil will can also help. Light oil is not poison and the minute amount you would actually get in the water supply would be so diluted by the time it got to a faucet, you would never taste it. Remember, it goes on the threads not inside the pipe.

I just wouldn't want to take that chance.

If it makes you feel better, use castor oil ...

It would make me feel better, thanks.

[ked]

Oil is toxic, caster oil will rot over time. Use plumber's lube, the stuff you put on shower valves to make them work smoothly. It is non-toxic for many years.

[hj]

If the manufacturers want lube on the compression threads let them put it on when they assemble it.

[JerryR]

What about using Dow 111 silicone lube on the threads. One tube lasts a lifetime?
http://www.bigbrandwater.com/dow111.html

I use this for o-ring lube on water filter o-rings.

Jerry

[Mikey]

At the rate I'm going, it looks like it will last for several lifetimes. Good stuff.