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Another noob question, this time about PTFE

Discussion in 'Plumbing and Central Heating' started by cjard, 16 Aug 2016.

  1. cjard

    cjard

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    The thermostatic shower valve unit I picked up has 3/4 female input connections, and 1/2 output connectors. Because I was geared up for 15mm right through, including all my tap connectors I picked up two 3/4 male to 15mm compression couplers (like this http://www.screwfix.com/p/male-coupler-15mm-x/82086 )

    There weren't any rubber washers in the bottom of the holes on this shower valve (unlike the other valves I've bought for the rest of the house) so I wound 12 turns of PTFE onto one coupler, wound it in, and it's fine. On the other one, i first had 12 turns and water was pouring out (well, dripping out at an exceptional rate).
    I re-did it, thinking I'd messed something up and it was better, but dripping. I've put 16 turns on and it's still weeping ever so slightly (in half an hour it didn't make a drip but if I rubbed the bottom of the union it would leave a water mark on my finger). Should I up it to 20 turns?

    In terms of basic PTFE technique, am i right in thinking that winding the coupler all the way to the bottom is actually detrimental because it forces the threads to one side of the groove, which might open up a path for water on the other side?
     
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  3. Dan Robinson

    Dan Robinson

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    Can't be a7sed with another PTFE thread (arf) especially if that numpty JohnD is lurking.

    Bin the tape and buy a bottle of liquid PTFE from screwfix.
     
  4. Aquaheat

    Aquaheat

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    Or a tub of Loctite 55.

    How long do you reckon this will take before PTFE on compression or adding a jointing compound on top of the PTFE is mentioned @Dan Robinson ?
     
  5. muggles

    muggles

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    I think you need to bin the PTFE and buy some fibre washers
     
  6. Agile

    Agile

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    Have you asked the makers if there should be washers?
     
  7. Dan Robinson

    Dan Robinson

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    I'm saying no more on the subject as my word is Gospel on this matter.
     
  8. Nige F

    Nige F

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    Dispenser of hemp from screwfix £7. Tub of paste. £3 Jobs a good un.
     
  9. Aquaheat

    Aquaheat

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    Well us RGI Gods know the commandments but i bet it still gets bought up! How's the land of the rising sun?
     
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  11. picasso

    picasso

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    Do you put ptfe and jointing compound ?
     
  12. Aquaheat

    Aquaheat

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    Do you mean me @picasso ? If so then God NO! Slight smear of compound on pipe after olive and thats it. No real need for it with copper olives but the brass ones like it. In reality they shouldn't need anything as its a mechanical joint but I've found a few weep so just do it now on everyone as it saves having to go back and redo the odd one which has wept.

    Jon
     
  13. Dan Robinson

    Dan Robinson

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    Spent today flying a 737 in a proper Boeing simulator. Very cool. Sitting in the second home watching the news as a typhoon is about to hit. Might scupper Disneyland tomorrow.

    Company email server has collapsed too though which has taken the shine off the evening. However, honourable SIL is here with the 1 month old nephew and all my little tricks for keeping babies quiet are coming back to me :cool:
     
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  14. picasso

    picasso

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    Just messing about (trying to see if any of the yokels would bite):D
     
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  15. Aquaheat

    Aquaheat

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    @picasso Here's a tutorial I made earlier for those wanting to know how to do compression joints properly. :whistle:

    DSC_0150 [90784].JPG
    Place backnut and olive onto pipe...

    DSC_0151.JPG
    Liberally apply jointing compound on the olive and pipe...

    DSC_0152.JPG
    Wrap plenty of PTFE over the compound and the length of the pipe ensuring its well covered and push fitting hard into place...

    DSC_0153.JPG
    Pull backnut over PTFE and tighten on to fitting. A perfect leak free compression fitting every time is a beauty to behold.
     
  16. picasso

    picasso

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    Its not every day you see a professional at work..........:censored:
     
  17. Dan Robinson

    Dan Robinson

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    You forgot to put compound onto the PTFE.


    Amateur
     
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