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Discuss PTF Tape and Compression Joints in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Jerry N

    Jerry N New Member

    Can anyone tell me whether PTF tape used on a compression fitting would degenerate?

    Also, where a plumber undoes the nut on one end of a compression joint is it correct that the connection at the other end of the joint will NEVER in any way be disturbed?

    The above queries may sound a bit odd but that is exactly what was said by an "expert" who attended my property after a very - and I do mean very - slow leak was discovered after a plumber undid and then a couple pf hours later reconnected a flexi pipe to an elbow connection. The expert said, in his experience, undoing one end of a compression joint will NEVER loosen up the connection at the other end and that PTF tape does degenerate and can do so within three years. Is he correct?


    Update ( I am new to this thread and I cannot see an option form me to comment on posts made so far)

    Thanks to those who have already responded. I should point out that the plumber says he did use a wrench to hold onto the elbow joint when he undid it and then did it up again. But what I need is independent confirmation that, even when the joint is supposedly tightly held using a wrench, the joint at the other end can still be disturbed. Also I am looking for comments which basically say PTF tape does not degenerate especially when it was used less than 4 years beforehand on the relevant joint.
     
    Last edited: Jul 16, 2017
  2. snowhead

    snowhead Well-Known Member

    If that was the case, then there would be millions of leaking joints around the Country.

    It would be imposssible to say NEVER.
    It would also be good practice to check the tightness of a second joint on the same fitting.
     
    • Agree Agree x 1
  3. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Of course compression fittings can but disturbed if you dont hold back on the fitting when undoing them as for ptfe degrading there would be a awfull lot of leaks springing up every day if this was true as long as its used properly it is fine may i ask why you have asked this cheers kop
     
    • Agree Agree x 2
  4. rpm

    rpm Trusted Plumber Top Contributor!!

    Guess you are here as you didn't like the answers you were given elsewhere then.
     
  5. Jerry N

    Jerry N New Member

    Oops - just seen this section! See above where I updated my original post.

    I have had responses from elsewhere all of whom have, in effect, said that a plumber or an "expert" cannot say that the undoing of a connection at one end of a compression joint will NEVER potentially loosen up the other end and that PTF tape doesn't degenerate. The more independent plumbers who effectively say that the better so far as I am concerned as that is evidence I can present to my insurers when I challenge the claims made by the plumber and expert
     
    • Friendly Friendly x 1
    Last edited: Jul 16, 2017
  6. Jerry N

    Jerry N New Member

    Also I would appreciate views on the attached pictures. From what can be seen, does it look like the olive shown was incorrectly installed? The slit in the olive was made when it was cut to allow it to be removed.

    WP_20170519_09_53_35_Pro.jpg

    WP_20170519_09_53_58_Pro.jpg

    WP_20170519_09_54_01_Pro.jpg

    WP_20170519_09_54_07_Pro.jpg
     
  7. Matchless.plumb

    Matchless.plumb Trusted Plumber Top Contributor!!

    I feel the olive was wrong,y installed you would ad a leak straight away or within days. If the leak appeared after years then I would assume it was correctly installed.
    It is quite hard to judge if it was wrong installed based on your pictures. I'd rather use jointing compound than ptfe. But everyone uses different things.
     
  8. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    It is hard to say but when you look closely there is a bit of errosion of the olive and disscoulouration i would say it is a old fitting expansion and contraction and heat could lead to leakage it would be quite difficult to get it wrong but cross threading of the fitting and not using a jointing compound could also cause a failure cheers kop
     
  9. mache

    mache Active Member

    Sounds like your looking to claim for water damage either through insurance company or against your plumber. Making judgements is extremely difficult without full disclosure. When was the work done, what exactly was done, was the leaking joint exposed or boxed in. If boxed in who did that? You mention a very very small leak how was it discovered and what damage has been caused.

    Any modification to a system has a possibility to affect the fabric of the original construction (not just plumbing but anything including buildings, roads, cars).

    Unlikely to get categoric answers, but more chance with full disclosure of events
     
    • Agree Agree x 3
  10. Best

    Best Trusted Plumber Top Contributor!!

    That olive is rotted! If you look at the edge you can see a lot of it is missing. Difficult one to call, to be honest, as the plumber probably should have never assumed the other side of the compression fitting was, (1) completely undisturbed (as how would he be sure?)
    and (2) was originally correctly done.
    and I now am adding (3) - he wouldn't know the fitting had corrosion damage.
    Sounds to me the plumber has tried to avoid a claim.
    The ptfe eroding comment is laughable.
    I do however feel sorry for the plumber if you are trying to claim from him for a leak on somebody else's work. If little damage done, I would accept it possibly isn't 100% his fault and forget it. Lots of old things break if you touch them.
     
    • Like Like x 1
    Last edited: Jul 16, 2017
  11. steadyon

    steadyon Active Member

    I think you are asking two distinct questions:

    1. Does the "other" side of a compression joint NEVER loosen when one side of the joint is undone and re-done?

    2. Does PTFE tape deteriorate over time?

    I don't think you are going to get a definitive answer to either question with any form of scientific backing. My own opinion, as given before, is that compression joints can loosen on the opposite side from that being worked on if the fitting is not secured against movement, but it is rare, particularly with elbows. I have never seen PTFE tape on joints of any age where the tape has degenerated, and certainly not to the point where a leak has occurred. I note you have not responded to the suggestion that a flexible hose was joined directly to a compression joint where the flexible hose terminal fitting was not designed for such connection.

    I think you might be well advised to get written confirmation of your "expert's" formal and scientific qualifications, his or her experience as a working plumber, and membership or otherwise of such bodies as the Society of Expert Witnesses, Academy of Experts or Expert Witness Institute.
     
  12. Chuck

    Chuck Top Contributor!!

    You need to talk to a solicitor and find out where the burden of proof lies in your case, what evidence if needed, etc. I'd be surprised if the scenario you describe needs expert investigation. It's more likely to turn on what was your plumber employed to do, whether he used reasonable skill and care and what he could reasonably be expected to observed during the course of his work.

    I doubt the opinions of the 'expert' are worth discussing. Unless you've missed out the part of the story where both sides agreed that this person was appropriately qualified to act as a 'Single Joint Expert' [*] what they think or say is not likely to be relevant. If, however, this person damaged the joint in question so a real expert can't determine cause reliably that may strengthen your case. Or it may not, which is why you need to consult a solicitor.

    [* What you really need here is a 'Single Joint Compression-Joint Expert' :) :). Okay, I'll get my coat...]
     
    Last edited: Jul 17, 2017
  13. GH77

    GH77 GSR Top Contributor!!

    "Never" is a very bold statement and the plumber was unwise to use this term, but sounds like he is on the defensive, if you pursued this to court he will deny liability, they may rule in your favour or his, but you can't be sure and to be honest is it really worth pursuing this purely on a financial basis? . how much damage was done? . if you're not happy with this plumbers work then I would advise not using him again and put the whole thing down to experience.
     
    • Agree Agree x 1
  14. Jerry N

    Jerry N New Member

    Thanks for all of the comments. But here are more issues I overlooked when I posted my previous queries.

    Where PTF tape has been would around the thread on a compression joint to act as a lubricant, if that joint is subsequently undone and then done up again, is it usual practise to just do the joint up again without removing the old PTF tape and then, once removed, to use new tape?

    When a flexi pipe is being attached to a compression joint I understand there is no olive to form a seal. Instead there is a gasket of some sort possibly a rubber O ring or a washer of some type. So some questions.

    Regarding the O ring or washer seal, firstly is it possible to overtighten the nut on the end of the flexi pipe crushing the O ring or washer thereby leading to a leak whether large or small?
    Is it common practise to simply reuse the O ring or washer or should the O ring / washer be replaced?
    As there is no olive which would form a seal, is it common practise to wind ptf tape around the thread on the compression fitting not just to act as a lubricant but also to act as a backup seal?
     
    Last edited: Jul 18, 2017
  15. steadyon

    steadyon Active Member

    1. Replace PTFE tape on thread
    My view is that it shouldn't have been there in the first place, so I wouldn't replace. Nor would I clean off any that was left on.
    2. A flexible hose should not be connected directly to a compression fitting. The sharp edge of the fitting can cut into the rubber seal / gasket in the flexi fitting. You can get special adaptors to go in the compression fitting (olive as usual) with the other end threaded (1/2" or 3/8" BSP) with a flat face to contact the flexi seal.
    3. As above, the sharp end of the compression fitting can damage the gasket.
    4. Most flexis have these seals captive in the end nut, so they cannot be replaced, although an additional fibre or rubber seal could probably be used OK if it is damaged. If not damaged they should re-seal OK if the flexi is re-used.
    5. PTFE tape is only designed to seal tapered threads. It is not designed to seal parallel threads, and won't act as a backup seal. If the original seal doesn't work (flat face to gasket), replace the faulty component.
     
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