Teflon Tape on Plastic Threads

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by bakechad, Jun 28, 2006.

  1. bakechad

    bakechad New Member

    Just finished my latest plumbing project.

    I installed a RO filter in my laundry room to fill up five-gallon jugs. Everything went very well and it was working flawlessly for the first day.

    The next day, two of the screw on connections for the plastic tubing started dripping. The owner’s manual troubleshooting section said to tape the threads if they leak. I did this to the first connection and it stopped dripping and I have had no further problems with that connection. The second connection is hard to reach, so when I taped it, I put on too much tape and it rolled up on the threads. Now this connection really leaks!

    So my question is how do I remove the tape without damaging the plastic threads?


  2. prashster

    prashster New Member

    The tape doesn't stick to the threads.
    You should be able to unscrew the joint and the tape should just peel right off. When you tape, make sure you go in the direction that the female side will screw so that the female side doesn't push against the trailing edge of the tape but rather goes with it.

    Also, only put enough tape to cover the threads completely - but not excessively (2 complete revolutions usually works for me - others and pros may differ).

    Third, you should consider using pipe joint compound. Some people prefer joint compound to tape. Some prefer tape to compound. Some prefer both...
  3. Gary Slusser

    Gary Slusser That's all folks!

    Four to six clockwise spiral wraps when looking at the end of the threads; from behind the threads, you go counter clockwise. That's makes the tape tighten as you screw the parts together,

    Joint compound not made for the specific type of plastic can damage plastic parts and will void warranties on many types of plastics.
  4. norcal1

    norcal1 Plumber/Owner

    Sounds like the plastic cracked...hope not.
  5. jimbo

    jimbo Plumber

    San Diego
    Too much tape on plastic is a problem. The plastic pipe industry recommends 2 wraps, then hand tight, then 1/2 wrench turn. Most plastic fitting leaks are caused by damage due to overtightening.

  6. You'd be surprised how many people don't have that knowledge in regards to plastic pipe fittings.

    #1 service call that I love to make money on:

    Threaded male adaptor into the A-coil pan on a furnace. Installers never dope or tape that threaded connection and it always leaks. Thanks guys! $$$
  7. Gary Slusser

    Gary Slusser That's all folks!

    Yes over tightening is the prime cause of failure of threaded plastic fittings.

    Unless the fitting is 1/24" or smaller, I find that for me to actually cover the threads with 2 layers of tape, I have to put more than two wraps on to cover all the threads... so I spiral the wraps up the threads and back down, which when I count is usually 4-6 wraps depending on the size of the fitting, such as 3/4" or larger, and two layers. Doing it that way on many plastic fittings for about 17 years, I've only had to go back once to fix a leaking threaded fitting, but then I tighten them with a wrench more than a 1/2 turn.
  8. Cass

    Cass Plumber

    Gary, That is how I have been doing my threads for as long as I can remember. The first few times they leaked and I just kept experementing untill I found a combination that worked.

    2 wraps of tape would cause you to have to overtighten the threads and may not be enough to fill in between the threads.
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