Compression fittings weeping

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Anthony Curtas, Oct 21, 2019.

  1. Anthony Curtas

    Anthony Curtas Member

    Joined:
    Oct 13, 2011
    Occupation:
    Engineer
    Location:
    Northern Virginia
    Hi all,
    I have two shutoffs I installed over the weekend that are weeping for lack of a better term. Over the course of 8 hours or so, enough water will accumulate to show up with a finger test. Never seems to develop a full drop to leak down (put paper down that should show any drops).

    I installed 3 others that are perfectly tight and not leaking. My methodology was to seat the pipe in as best I could, push in the ferrule to make sure it seated in the shutoff fitting, hand-tighten as best I could, then about 1/4 turn with the wrenches after that. All of them required a second tightening past the 1/4 turn to seal, but not much.

    The two that are still weeping are probably at a full 1/2 turn and feel really tight, but still giving me that very slow leak.

    What are my options here? I was going to replace the ferrules, but I was wondering if pipe dope or even trying a bit more force would be worth it first? (but I don't want to permanently dent the pipe or crack the fitting nut).

    Thanks,
    Anthony
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Go another 1/4.
    I don't know if pipe dope at this time will help, but you could try. The lube on the ferrule and around helps lube. A little plumbing lube on the threads can help by letting your your efforts more into the tighening and less into thread friction.

    I was worried about crushing the pipe. I cut out a leaky compression connection that I was afraid I had over-tightened, disassembled, and found I had not dented the pipe. The deal is, unless your wrenches are very long, you are unlikely to over-tighten. Stubby wrenches are not sufficient. I am not a plumber.

    Do use good wrenches rather than loose adjustable wrenches. Flare nut wrenches are really good in letting you apply more torque without rounding off the hex.
     
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  4. Anthony Curtas

    Anthony Curtas Member

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    Oct 13, 2011
    Occupation:
    Engineer
    Location:
    Northern Virginia
    I'm using huge channel locks with foam on the jaws to hold the fitting and a 9" or so adjustable wrench on the fitting (a standard size, not a long one) I have open ended wrenches in my auto-tools, I can try one of those for the extra oomph. My SAE flare wrenches are not big enough for plumbing work, though.

    I'll give it another 1/4 then and wait overnight. Sounds like I can just delay swapping the ferrules in case tightening doesn't work. I should probably buy a few extras of those anyway.

    Thanks.
     
  5. hj

    hj Moderator & Master Plumber Staff Member

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    Plumbers do NOT use a "formula" such as "1/4 turn past hand tight". We tighten them until they are snug, regardless of how many turns it takes.
     
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  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Your calibration of snug may differ from others. Some might think of snug as hand tight. Yours might be less than it was the times you rounded off the nut.
     
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  7. Anthony Curtas

    Anthony Curtas Member

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    Oct 13, 2011
    Occupation:
    Engineer
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    Northern Virginia
    I read the 1/4 turn past finger-tight several places and figured that was a good starting point. Brasscraft's instructions say 3/4 turn past hand-tight. I'm not using a Brasscraft shutoff, but at least I have a reference point. I'll let you all know how it goes.
     
  8. Sylvan

    Sylvan Still learning

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    Occupation:
    plumbing - fire suppression - boiler inspector
    Location:
    New York
    Sometimes Handymen loosen the compression nut and use Teflon tape one or two turns on the ferrule and then tighten the nut snugly
     
  9. hj

    hj Moderator & Master Plumber Staff Member

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    Occupation:
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    Since I have NEVER "rounded off the nut", I am not sure what you are talking about.
     
  10. dj2

    dj2 In the Trades

    Joined:
    Aug 13, 2013
    Location:
    California
    Did you use a new sleeve?
    If it's leaking, it's not tight enough.
    On the other hand, with soft copper, over tightening can lead to new problems.
    Try again, and this time use a 12" crescent adjustable wrenchs or heavier. One to hold the angle stop and one to tighten.
    Remember: don't over do it.
     
  11. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    Normally I can install right out of the box. Sometimes I put some pipe dope on the threads. I've never used tape on them.
    Like hj I just tighten them on. I have no idea what finger tight is or how far past that would be.
     
  12. Anthony Curtas

    Anthony Curtas Member

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    Oct 13, 2011
    Occupation:
    Engineer
    Location:
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    Well I switched to the 12" adjustable and gave them another heave ho. About 1/4 turn on one and only half that on the other and it seems to have stopped. I'll keep an eye on it as I have a day or two before the counter goes in. (it is so much easier to work on these from above than laying in the cabinet).

    Much better with the longer wrench and honestly didn't feel like it was over-tightened. I was just worried about overdoing it, which it seems I did not. So no tape or dope necessary.

    Thanks all!
     
  13. Tuttles Revenge

    Tuttles Revenge In the Trades

    Joined:
    Oct 15, 2014
    The "1/4 turn past hand tight" ONLY applies to compression fittings that have soft rubber washers as the seal.

    A compression fitting made up of a brass ferrule that is compressing over a hard tube requires enough force to seal the fitting but also to compress into the tube to make an impression in the tubing so that it doesn't blow out. Inadequate tightening of these fittings can and will result in a blowout of the tube which will create a massive leak.
     
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