Re: Threaded joints / boss white + hemp

Discussion in 'UK DIY' started by Andrew Gabriel, Nov 28, 2003.

  1. In article <3fc73f5e$0$13351$>,
    "Christian McArdle" <> writes:
    > I've never done threaded joints before. The standard instructions always
    > seem to say to wrap hemp around the threads opposite to the way it gets
    > screwed in. I'm not really sure what this means.
    >
    > 1. How thick a clump of hemp should be used?
    >
    > 2. Do you wrap the hemp inside the channel of the thread, or across the
    > threads?
    >
    > 3. If you run inside the threads, do you start from the end away from the
    > joint or towards the joint?
    >
    > Christian.
    >
    > P.S. this is for radiators, no potable water involved.


    Use PTFE tape, much easier. I use about 10 turns, wound such that
    it is not unwound by the action of assembling the join. Join should
    become tight when assembled -- if not disassemble, remove mangled
    tape and replace with more turns. If you can check for leaks using
    compressed air to at least 2 atmosphere's pressure with gas leak
    detector spray, that's much easier than doing it by refilling with
    water and looking for drips, draining down, remaking joint, etc.

    --
    Andrew Gabriel
     
    Andrew Gabriel, Nov 28, 2003
    #1
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  2. Andrew Gabriel

    Andy Hall Guest

    On 28 Nov 2003 14:12:09 GMT, (Andrew
    Gabriel) wrote:

    >In article <3fc73f5e$0$13351$>,
    > "Christian McArdle" <> writes:
    >> I've never done threaded joints before. The standard instructions always
    >> seem to say to wrap hemp around the threads opposite to the way it gets
    >> screwed in. I'm not really sure what this means.
    >>
    >> 1. How thick a clump of hemp should be used?
    >>
    >> 2. Do you wrap the hemp inside the channel of the thread, or across the
    >> threads?
    >>
    >> 3. If you run inside the threads, do you start from the end away from the
    >> joint or towards the joint?
    >>
    >> Christian.
    >>
    >> P.S. this is for radiators, no potable water involved.

    >
    >Use PTFE tape, much easier. I use about 10 turns, wound such that
    >it is not unwound by the action of assembling the join. Join should
    >become tight when assembled -- if not disassemble, remove mangled
    >tape and replace with more turns. If you can check for leaks using
    >compressed air to at least 2 atmosphere's pressure with gas leak
    >detector spray, that's much easier than doing it by refilling with
    >water and looking for drips, draining down, remaking joint, etc.


    In this connection, it makes sense to run the system for a day or so
    after completion and initial flushing to check for leaks and pressure
    drop. Then put in some system cleanser and run for a few days,
    checking again. Finally flush and add inhibitor.

    This avoids wasting inhibitor if draining is needed to fix a leak.

    On another practical note here, using Pegler Terrier lockshield valves
    which can be bought with a drain cock on the radiator side means that
    if work is required, you can turn off this valve and the TRV using the
    isolating cap that comes with them. You can then drain easily and
    fix a problem in this area without a total drain down. These are a
    nice quality valve IME.

    (Christian, for your benefit, if you don't have valves, Travis Perkins
    heating centre in Reading near to PC World in Basicngstoke Rd. have
    the Pegler ones)



    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Nov 28, 2003
    #2
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  3. Andrew Gabriel

    Andy Hall Guest

    On Fri, 28 Nov 2003 16:04:29 -0000, "Christian McArdle"
    <> wrote:

    >> (Christian, for your benefit, if you don't have valves, Travis Perkins
    >> heating centre in Reading near to PC World in Basicngstoke Rd. have
    >> the Pegler ones)

    >
    >I do already have the valves. However, by some stroke of coincidence, I have
    >indeed bought the stated valves several weeks ago from that very branch of
    >Travis Perkins, along with some Invensys TRVs.


    Well there's a coincidence :)

    >
    >As for the connections, in practice, I have just would a large "sheet" of
    >hemp round the threads in no particular direction with a large mound of Boss
    >White spread over the top (at 85p a tub, I'm not worried by wastage!) I
    >wiped off excess Boss White with bog roll. We'll see if it leaks soon
    >enough. ;-)


    I think that that ought to do it. Of course, smelling of Boss
    White and hemp and going into the merchants ought to be worth a few
    more points of discount.

    However, you do need to practice your Whitley accent, call everyone
    "mate" (because that is their name), make sure your backside is
    hanging out of your jeans and remember to leave the gold card at home.
    :)


    >
    >Christian.
    >


    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Nov 28, 2003
    #3
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