Need help. Tight seal/Leak

Discussion in 'General Discussion' started by John T, Oct 5, 2019.

Help Support Plumbing Forums by donating:

  1. Oct 5, 2019 #1

    John T

    John T

    John T

    Member

    Joined:
    Oct 5, 2019
    Messages:
    5
    Likes Received:
    0
    Location:
    Salem, OR
    I posted this earlier but perhaps in the wrong section . My apologies .

    I’ve been working under my house replacing most of the galvanized half-inch with PEX.

    I have one long continuous pipe that runs to the far side of crawlspace with cery difficult access. I found the spot to tie in but While trying to get the T loose I started to unscrew the long stretch of galvanized pipe. I only turned it about a quarter turn. Then retightened it.
    I’m wondering if Breaking the original bond will cause this point to start leaking.
    It is out of my sight and very difficult to access. However I don’t want a leak either.

    Any opinions on if a quarter turn on an old connection will start leaking?

    Thanks in advance.
     
  2. Oct 5, 2019 #2

    Jeff Handy

    Jeff Handy

    Jeff Handy

    Well-Known Member

    Joined:
    Jul 5, 2019
    Messages:
    341
    Likes Received:
    55
    Location:
    Chicago suburbs
    We have pbly all turned a galvanized pipe or nipple that we prayed would not budge, if we had our fingers and toes fully crossed.

    Why don’t you just take that iffy galvanized pipe out?
    You are trying to reduce the amount of old galvanized anyway.

    Can’t you go back and finish unscrewing it, then in its place add a copper pipe soldered to a brass adapter?
    Just wrap the threaded end with teflon and/or pipe dope.

    But finally, I have found that even pipes you did not want to rotate will still keep a good seal, if retightened enough.

    Unless they are super ancient, and the threads are almost gone. Not common in my experience, but ask the pros to jump in.
     
    John T likes this.
  3. Oct 5, 2019 #3

    frodo

    frodo

    frodo

    Just call me Macgyver Professional Supporting Member

    Joined:
    Sep 28, 2014
    Messages:
    7,645
    Likes Received:
    2,368
    Location:
    ,
    prolly not,

    a pipe thread is tapered into the fitting.
    the threads on the pipe are a c---hair shorter than the thread on the fitting.
    this leaves a small space at the bottom of the fitting like a channel
    the pipe dope is packed into this space to seal it. if you backed the pipe off then re tightened it
    and a little more, then all you did was repack the dope into the channel
    but,
    if you did not tighten it ''a little more'' then it is a 50/50 it will leak

    you are replacing 1/2'' galvanized piping with pex pipe
    below is a side by side ID [inside diameter] chart.
    note.... that pex id is actually the size of 3/8'' galvanized id pipe
    i thought you should be aware of what you are doing

    galvinized_pipe_id.png
     
    John T likes this.
  4. Oct 5, 2019 #4

    John T

    John T

    John T

    Member

    Joined:
    Oct 5, 2019
    Messages:
    5
    Likes Received:
    0
    Location:
    Salem, OR
    Thanks for your responses. The are the answers I was looking for. I will try and tighten it back up and then test. Problem is it’s difficult to see the far connection for leaks. Fingers crossed.
     

Share This Page