New Nuair Leaking - my Bad?

  1. Submariner1 Member

    Messages:
    96
    Location:
    Berkshire
    The new compressor lost 8.2 Bar in 22 hours ...
    Then I discovered, the leak was where I had fitted the supplied Euro QR! (The only joint the user has to make).
    The QR fitting was supplied with Off white coloured tape pre-applied to the threads.
    E2686E47-AE34-4D01-BBE9-345A99CC59D3.jpeg
    Couldn’t hear the leak, but Diluted fairy liquid was blowing 1” bubbles like crazy. Note the pic where the connector is screwed fully home.
    I redid the joint with 5 layers of white PTFE Tape. Almost as bad. Tried again with 7 revolutions of tape, better but still small bubbles. ( note fitting was fully in ).

    Redid it again!
    This time with 9 layers of ptfe tape.
    A1BE6F18-4D94-42ED-9BFD-55A9AF435E71.jpeg
    Much better ... almost leak free; but when I put some oil on the joint, you could just see some micro bubbles over a 5 min period.

    I thought 3 layers of tape was all one needed on a tapered joint? Am I wrong?
    Note the threads on the fitting and the tank, look clean cut and undamaged.

    Would It be better to redo it with 11 revolutions of tape or use something like Locktite 572?

    what is the best thread sealer that would seal these threads, yet undo without heat, or the absolute minimum heat.
     
  2. eddie49 Member

    I suspect that the female fitting on the tank is BSP parallel ( BSPP ), not tapered ( BSPT ). It is designed to accept a tank end-plug, and seal using an O-ring or a flat rubber disc washer.
     
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  3. Anguz

    Anguz Forum Supporter

    Messages:
    677
    bedfordshire
    loctite custard... cant remember the number but got a tube in my van
     
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  4. waddycall

    waddycall Member

    Messages:
    1,229
    United Kingdom
    10-12 wraps on the thread then keep wrapping around near the end of the thread to create a build up that will form a ptfe washer against the shoulder of the hex as it winds in. Don’t be afraid to put more on.
     
  5. Submariner1 Member

    Messages:
    96
    Location:
    Berkshire
    Maybe the thing to do is get a 1/2 BSPP plug and a dowty washer, and save this non corroding QR fitting for use as a spare on the on board regulator.

    It does seems to be holding pressure much, much better; but I will see how much air is lost over 22 hours; and if not too significant, just live with it. Or try once more with 11 layers of PTFE!
     
  6. Submariner1 Member

    Messages:
    96
    Location:
    Berkshire
    Thanks seems a good plan, as with nine wraps one can hand screw it in a long way.
     
  7. waddycall

    waddycall Member

    Messages:
    1,229
    United Kingdom
    It probably just needs building up a bit. The theoretical perfect world of what you should use on a thread and how much doesn’t really exist!
     
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  8. zzr1200

    zzr1200 Working at 650 ft on open steel work

    Messages:
    4,032
    Location:
    Glapwell, Chesterfield, Derbyshire.
    Studlock works as well, but is tad hard to undo if required...
     
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  9. eddie49 Member

    The on-board regulators on small compressors are often restrictive, and so it is quite common to replace a tank end-plug with an air connector to get a high flow rate supply for high-consumption air tools.
     
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  10. Brad93

    Brad93 M J B Engineering

    Messages:
    10,396
    Location:
    Essex
    Sod the PTFE tape you need Loctite 55 cord.

    Or loctite thread sealant, I forget the number it’s a gel.
     
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  11. Submariner1 Member

    Messages:
    96
    Location:
    Berkshire
    Yep that's what they say its for.
     
  12. premmington

    premmington Member

    Messages:
    2,023
    Location:
    Norfolk
    What it really needs is an isolating crane valve between the tank and quick fit connector for starters... :thumbup:
     
  13. mtt.tr

    mtt.tr Member

    Messages:
    4,046
    Essex England
    Have you wrapped the ptfe in the right direction as in anti clockwise
     
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  14. pedrobedro

    pedrobedro Man at Matalan

    Messages:
    10,705
    Location:
    CX Derbyshire
    Slap some Boss White round it then tighten it up and leave it to set.
     
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  15. hotponyshoes Member

    Messages:
    3,379
    Location:
    Somerset. Uk
    Stick an o-ring over the stem of the fitting.
     
  16. Submariner1 Member

    Messages:
    96
    Location:
    Berkshire
    Good news, despite seeing micro bubbles (appearing) very slowly last night, when oil was put on the joint.
    This morning there was no pressure loss. ( well none I could discern with this guage.
    Either this weeping of air has self sealed (doubtful), or as its much warmer this morning (unheated garage).
    The air expansion has Compensated for any Minute loss of air Overnight.

    at least I am on the right track, as before the 50L tank would be almost empty.
    And now unless I had bubble tested with soapy water and oil I would (incorrectly) say over 12 hours there was zero air loss.
     
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  17. Malky Member

    Messages:
    144
    Location:
    Scotland
    Should it not have a ball valve first.
     
    jsf55 likes this.
  18. eddie49 Member

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  19. bricol Member

    Messages:
    1,520
    N.Yorks, UK
    Surely clockwise as you look at the end of the thread, so when you wind it in, its not trying to undo it.
     
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  20. mtt.tr

    mtt.tr Member

    Messages:
    4,046
    Essex England
    Your right, wasn't so bright this morning.
     
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