Cleaning Threads Before Reapplying Threadlock

  1. Pollys13

    Pollys13 Member

    Messages:
    328
    Location:
    Wiltshire UK
    I did Google I may have used the wrong search terms but I couldn't find any relevant information.
    I need to remove some fittings to replace a faulty regulator, using a Butane hand torch. I'm assuming I will need to clean up any gunk off the threads, before I reassemble, if so how do I go about doing this, Acetone, small brass brush?
    I'll be using low strength Flomasta liquid PTFE this time.
    Thanks.
     
  2. addjunkie

    addjunkie Member

    Messages:
    5,449
    Location:
    Northumberland. Reet oot in the sticks
    Thread lock and thread sealant are two different things, your planning to use sealant. Gas fittings like regulators and such dont normally have sealant on them, and if you do it needs to be the right sealant. Thread lock is to stop things vibrating loose.

    As for cleaning threads I just use a small wire brush.
     
    mtt.tr and wyn like this.
  3. awemawson Forum Supporter

    Assuming things are looking physically clean, I give them a squirt of carburettor cleaner then a blast of compressed air before applying any form of Loctite be it thread lock or pipe sealant.
     
  4. Pollys13

    Pollys13 Member

    Messages:
    328
    Location:
    Wiltshire UK
    OK thanks.
     
  5. Pete.

    Pete. Member

    Messages:
    8,655
    Location:
    Kent, UK
    I use a wire brush if there's any sign of old deposits, otherwise brake cleaner and a wipe over.
     
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  6. earthman Member

    Messages:
    1,149
    Yes, good point.:)

    I've just thought of this, what if the connector/fitting has to seal fluid but also cope with vibration/movement, which do you use then?:dontknow:
     
  7. Pete.

    Pete. Member

    Messages:
    8,655
    Location:
    Kent, UK
    Lock & Seal.
     
  8. earthman Member

    Messages:
    1,149
    Never heard of it.
     
  9. brightspark

    brightspark Member

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    27,632
    Location:
    yarm
  10. bricol Member

    Messages:
    848
    N.Yorks, UK
    Loctite 575. Excellent stuff - never had a leak using it. Comes apart again with no hassle. Instant use. No need to be too over the top on thread cleaning - just apply and screw up. I have used it at 25 Bar on 1/4 NPT fittings into 1/4 BSP successfully - although I don't recommend it.
     
  11. timgunn1962 Member

    Messages:
    76
    Location:
    Lancashire UK
    The Flomasta liquid PTFE is pretty boring stuff: IME it just works. For critical stuff and hydraulic pressures, Loctite et al make products that are "better" engineered, but the Flomasta stuff is cheap and plenty good enough for typical 10 Bar(-ish) compressed air systems.

    Clean off anything that's on the threads from before, using whatever you have to hand. A brass brush and brake part cleaner is my go-to if I'm in the workshop, maybe running a tap through the female threads to clean them up if I'm feeling particularly keen, but out on site it's usually a case of scraping off the worst of any previous sealant from the male thread with the point of my penknife and wiping it on a not-too-obviously-oily bit of my sweatshirt. I'll twist a bit of whatever I can find (often the sleeve of said sweatshirt) into the female thread to sort-of clean it. Apply the liquid PTFE to the male thread, and a little to the first female thread if it looks like it needs it, screw in the fitting, wait 10 minutes and pressurize. In the workshop, I'll then test with a leak-test aerosol. Soapy water also works. On site, it's usually spit.
     
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  12. timgunn1962 Member

    Messages:
    76
    Location:
    Lancashire UK
    Sorry, missed the Butane reference. I use the Flomasta liquid PTFE (from Screwfix) on Propane lines and I've never had a problem with it. However, I've not seen a "proper" spec for it that shows it is approved for LPG.

    I have a feeling the Tru Blu equivalent, available from Toolstation, is suitable for LPG. The PDS lists "Vapor Propane Piping".
     
    mike os likes this.
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