Sealing SCH 80 PVC threads that leak

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by DTAZ, Jul 11, 2019.

  1. DTAZ

    DTAZ Member

    Feb 14, 2017
    Hello all,

    Anybody run into this problem? I have built a vacuum breaker for an irrigation system and made the above ground parts out of SCH 80 PVC. I've got a leak that won't quit. The short nipples that are available at my irrigation supply company are cast with less taper to the threads than longer nipples which have cut threads . I've nearly bottomed out the nipple into its adjacent fitting and still have a weeping leak after multiple rounds of assemble disassemble. Started with three turns of Fast Tape and finally resorted to just adding three more turns over the existing tape after four tries... Suggested solutions (other than copper pipe please).
  2. jadziedzic

    jadziedzic Member

    Aug 4, 2006
    New Hampshire
    Buy a reasonably inexpensive (Ridgid?) die of the appropriate size, buy a longer nipple with cut threads, cut it to length, thread the cut end? Even a Harbor Freight die set would probably be better than the cast nipple.
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  4. plumber69

    plumber69 In the Trades

    Jun 20, 2014
    Prince Rupert, British Columbia
    How bad of a leak? Small threaded leaks usually seal themself
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