Compression fitting stops leaking by itself ?!

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Old 08-07-16, 02:20 PM
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Compression fitting stops leaking by itself ?!

Installed a new compression fitting to sink, had to resort to the proverbial overtightening (read below why and what I may have done wrong). The new fitting was leaking (dripping ~3 drops per minute), then a couple of hours later it stopped leaking. Has been dry overnight.

Is this normal? What should I do? Leave alone or try some remedy. I don't think I should tighten it any more. It's already overtightened.



Details:
The semi-flexible hot water connection to my sink started leaking last night (rubber seals completely aged and disintegrated-likely the originals from when house was built in 1990). This is how it was:



Now, because the existing compression fitting (to 1/2" copper pipe) was the old multiple turn style (I have found that after a few years these never fully close and also have a tendency to leak from the stem), I decided to get a new 1/4 turn compression fitting.

Unfortunately, upon removing the old fitting, I discovered that it must have been overtightened during the original installation (1990 when house was built). So the ferrule was quite stuck
As a side note, I should have suspected this it because when I redid the compression valves in the kitchen sink I also found the fittings overtigtened and had a hard time getting the new ones to seal again.

So, I tried to re-use existing ferrule and nut with the new fitting... but they did not seal even under moderate overtigthening.

So (plan B) I just used an automotive puller to pull out the ferrule. Towards the end, I experienced a lot of resistance on the puller so I left the ferrule very close to the end of the copper pipe
and partially cut the ferrule with a hacksaw, then snpapped it open with a screwdriver, being VERY CAREFUL not to dent the copper pipe. Indeed no damage to copper pipe.
However, as you can see from the photo, the original overtightening seems to have deformed the copper pipe (you can see the saddle in the copper pipe diameter in the photo, and I imagine this is not normal -- it’s a sign of overtightening right?))



In any case, I put in the new ferrule and gave it a try, while already planning in the background how I may have to sweat a copper pipe extension etc.
Sure enough after normal tightening (hand tight + 1/2 turn) the compression fitting was leaking quite a bit (one drop per second). So I tightened another 3/4 turn and the flow was reduced to about 1 drop a minute.
I tightened a bit more thinking that perhaps it may seal, however after tightening another 1/4 turn the leak actually increased (Uh Oh, better look where that propane torch is, I thought,...)

Well, I gave it another 1/4 turn and the flow reduced again to about one drop a minute.

Frustrated, I left it as is, since it was 10pm and we had to cook and I did not want to end up having to shut off the water to the house.

But then,... when I checked about 2 hrs later, the leak seemed to have stopped. This morning, things were still dry, no drops in the bucket either?!?

Long story short, should I leave it as is? Or is this high risk for leaking in the future? I wigled a bit the fitting just to see if perhaps I had a very borderline seal, but it did not leak.

I cannot explain this and wonder what to do, so I'm turning to the experts (or other DYIers who ended up in a similar predicament).

Any advice appreciated.

P.S. I'd also like to replace other (the cold water) compression fitting since I'm doing this, but I'd rather avoid the same complications and uncertainty.
 
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Old 08-07-16, 02:38 PM
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...after normal tightening (hand tight + 1/2 turn)...
I would not consider a half-turn past hand tight as normal. To me normal is no less than a full turn and often a full turn plus another half-turn beyond hand tight. Even the high quality Swagelok stainless steel fittings need a full turn and the cheap brass fittings from the mega-mart homecenter need more.

It is NORMAL for the ferrule to compress the copper tube/pipe. If it doesn't the fitting is apt to slide right off the pipe or leak or both.

And yes, a slow leak MAY stop on its own. This is especially true if you have high mineral content in your water. I personally would not mess anymore with a fitting that you had properly tightened (more than a half-turn past hand tight) that originally had a small weep but sealed itself after a few hours.
 
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Old 08-07-16, 03:27 PM
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Thanks for the clarification Furd,

Actually I misread/misquoted the instructions. Tightening instructions that came with the fitting itself say: "...1/2 turn after the nut begins to take hold or bite into the tube". And indeed I set my reference to when the fitting started being snug to the pipe. Then I went that extra 1/2 turn, but it leaked, so I tightened some more, and more.. . I sort of expected having to tighten beyond the instructions since the pipe was not new, but I'm quite a bit past that. I'd guess I've torqued it to about 20-30 foot pounds, and that is while having applied some plumber's silicone grease to the threads. This is a generic fitting from Lowe's.

I'll leave it alone for now.
 
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Old 08-07-16, 03:44 PM
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If you feel the new fitting was not over tightened (beyond use), I would remove it.
Use a puller if necessary.
After the old ferrule and nut are pulled off, clean the copper with emery cloth.
Slide on the new nut. Coat the inside of the ferrule with pipe dope and slide it on. You want a coating of dope between the inside of the ferrule and the outside of the pipe.

Do not overtighten the nut. The ferrule doesn't need to be compressed against the pipe. Only the very thin edges of the ferrule need to dig into the pipe.
This is usually wrench tighten until ferrule grabs (stop will not pull off easily) plus 1/2 to 3/4 turn.
 
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Old 08-07-16, 07:18 PM
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Ok, I just replaced the other (cold water) compression fitting on the same sink. This one perhaps required even more torque.

So, I removed the old ferrule. This one was stuck too.

But is it normal for the 1/2" copper pipe to be this deformed? See photo below. And see how much smaller that pipe is compared to the new ferrule! Is this normal?




In any case, I gave it a try. I put plumbers silicone grease on the copper pipe, inside and outside ferrule, and nut threads.

Here is how things progressed:

-Hand tightened the compression fitting nut.
-Tightened another 1.5 turns: It took that many turns to get the fitting to just grab onto the pipe. But torque is still relatively light (estimate 10 lb-ft torque)
-Tighten another 1/4 turn and test: Leaking
-Tighten another 1/4 turn: Still leaking 1 drop every 10"
-Tighten another 1/8 turn
-Tighten another 1/4 more, at this point the nut starts squeaking as I turn, in spite of the grease.
-And another 1/8 turn squeaking (estimate 30 lb-ft torque at this point --turning the nut takes significant effort at this point): Still leaking 1 drop every 35"
-Another 1/10 turn, squeaking: Still leaking one drop every 45"
-Another 1/16 squeacking, (perhaps 35lb-ft now), the whole fitting turns just a tad bit (yes, I'm holding it with two opposing wrenches): Seems to have stopped leaking!


Look at the nut though, it is essentailly at the end of the tread, that ferrule must be smashed inside. But no leak so far.



I have 5 more sinks and 3 toilets to eventually redo this way in this house. There's got to be a better way… less work…more reliable… more predictable at least…

I think I'm going to try the dope on the next one. I am tough worried that a non-hardening dope may be eventually be pushed out of whatever small gap it is sealing -- and I'll get a leak at a later date. Or perhaps my mental model of how pipe dope works is incorrect.
 
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Old 08-07-16, 11:53 PM
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Having the copper that compressed is not normal, the person that originally installed the stop valves must have had a gorilla tighten them.

I do not advocate using any kind of "dope" on the pipe/tubing or ferrule. However, in your case it might work. It seems to me that the ferrules and fittings being sold in the mega-mart homecenters (made in a communist Asian country) are far inferior to what was made in the USA but that is another story. IF you had a means of soldering on valves without using a torch (I'm sure that you don't) that would be my suggestion.

At this point I say go ahead and try the goo along with tightening the heck out of the nut. You won't make it any worse than it is now.
 
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Old 08-08-16, 12:40 AM
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I wonder if a push fitting such as Sharkbite would work or is the pipe to deformed?

I wonder if there is enough pipe to get a flaring tool on it? The hole in the wall for the pipe could be enlarged slightly to temporarily allow the flare nut to be slipped back. The solid escutcheon removed and a split escutcheon could be slipped on after the connection.
 
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Old 08-08-16, 08:14 AM
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The copper pipe is deformed badly, beyond use IMO. I can't believe the compression fitting isn't leaking or the nut cracked.

I would solder on a 1/2" pipe adapter and use 1/2" pipe inlet valves.
Sharkbite fittings won't work.

All your valves are probably overtight. I usually don't recommend it but for any other valves you want to change, I would try to use the old nut and ferrule.
Clean off the old ferrule and apply Teflon paste to the valve threads. Tighten until snug and check for leaks.
 
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Old 08-08-16, 03:41 PM
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Thanks for all your replies, this is quite helpful.

Since it's not leaking (I can't believe it either), I think I'll leave this one alone for now. What's the risk? Could the nut just crack sometime later without me even touching it?

Soldering :
I'm attracted to the idea of soldering on an adapter. Handyone, I imagine you mean a copper sweat to male thread adapter and then get a female thread valve?



I guess the pipe deformation is not an issue with soldering?
I'm, of course, a bit weary of soldering such a short stem. On one hand, it's only 1/2" pipe so it should heat up quickly ("it's only waffer thin" as Monty Python would say…), I'll keep the flame mostly on the adapter, then as soon as the pipe melts solder I apply and I'm done?

I would, of course, put a copper or aluminum shield plate to avoid burning the wall, perhaps even a small piece of wet cloth around the pipe right at the wall? Or even open up the hole in the wall a bit, to get a small wet rug around the pipe just a little deeper. What is the main risk? Fire? or desoldering the other end of the pipe inside the wall?


Solder valve without torch? How is that done? I googled it but not much came up.


Dope :
What type of dope? Non hardening I imagine? I have "Great White" dope with PTFE. Perhaps I'll try it on the next one. If I can get it to seal without gorilla tightening then I'd feel better about the reliability of my seals.
Reliable seal is my main concern here. This sink leaked, because the rubber seals on these 25 year old semi-flexible metal supply lines has deteriorated. So I imagine that the other 5 sinks and three toilets in the house (which have the same original semi-flexible metallic supply lines) will soon start leaking. So the main purpose of proactively replacing the valves and supply tubes is to get a reliable seal, and a socondary objective to get the 1/4 turn valves which are presumably better (and will likely continue functioning after many years? as opposed to the multiple turn ones?). I don't want to trade this aging unreliable setup with unreliable compression seals.




I tried using the existing ferrule, but seems like that had a tendency to leak even more in this case -- though I did not get up to gorilla levels of tightening when I tried that on the first valve.

Finally, a relavant issue is that water pressure at my street is 110PSI, reduced to 55PSI through a pressure regulator. But I've had the pressure regulator go bad bofore. So all seals should be 110PSI proof, at least for long enough for me to realize the pressure regulator has gone bad.
 
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Old 08-08-16, 04:18 PM
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I guess the pipe deformation is not an issue with soldering?
Not as much of an issue, the gaps can be filled with solder in most cases.
The first rule of sweating copper is the pipes must be clean and dry. I would also recommend Mapp gas instead of propane, it will heat the adapter much quicker.

If you don't want to use the adapters, the wall must be opened up and new stub outs soldered in.
That would actually be the best fix from the beginning.
 
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Old 08-10-16, 06:05 PM
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Thanks everyone for the advice.

I'll leave this sink alone for now since it's not leaking. I'll just make a note it is vulnerable and perhaps address it at a later time.

As for the other fixtures, I'll eventually get to them but it may be a while.

Whatever work I do on these, I'll post the results.
 
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