Connecting Old Gal Nipple to PVC

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by bbillcee, Dec 10, 2008.

  1. bbillcee

    bbillcee New Member

    Messages:
    101
    Location:
    NY
    i have an old 2" gal nipple that used to go to a 2 in trap under the sink.

    should i use a no hub with sleeve to transfer to PVC then do all new trap etc in PVC

    or use 2" inch to 1 1/2 reducer then use all 1 1/2 brass traps etc

    which is most pro job? thanx
  2. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    I don't know the most "pro" answer, but since no pro has responded, I'll take a shot.

    Whenever I come across a galvanized stub-out, I like to screw on a FIP (female pipe threads) PVC adapter using teflon tape. In your case, you'll need the adapter to reduce from 2 in to 1.5 in. Next, I cement on a standard trap adapter to the spigot (SP) end of the adapter and now you are ready to install your 1.5 in PVC trap.

    This is what a trap adapter looks like:

    Attached Files:

  3. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    I do not advocate the use of any female plastic thread to connect to a metal male thread ever. It is almost a guaranteed leak even on a drain.

    What is the condition of the thread?
    If it is good you and put on a reducing coupling, then a 1 1/2" nipple then a slip joint washer and nut and put the tubular p-trap right into it.
  4. bbillcee

    bbillcee New Member

    Messages:
    101
    Location:
    NY
    well the nipple was screwed i was able to get it out and replaced with new nipple then i put the existing heavy duty brass trap back on that reduces to 1 1/2.....still planing the rest out i will definately be using brass
  5. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    Sounds like you have it under control.
  6. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    I have never had a leaking problem when I screw on a nice deep-threaded FIP PVC adapter using teflon tape. I have seen leaks, however, when people try to screw either a metal or a plastic slip-joint nut directly to the galvanized pipe. The metal nut will eventually rust away, and that rubber seal is guaranteed to disintegrate over time and leak.
    Last edited: Dec 11, 2008
  7. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    A metal female with a plastic male into it is okay but not vice versa. I prefer to avoid any plastic to metal threaded connection myself.

    As for the metal nuts rusting, that only happens when you use zinc plated steel nuts. I avoid those and use brass slip joint nuts.
  8. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    What about when you need to transition from galvanized to PVC? Most P-traps today are PVC, and for good reason.

    Isn't the seal used with the brass slip-joint nuts the same black rubber thing that always deforms, deteriorates, and eventually, leaks?
  9. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    If I am transitioning from Galv. to Schedule 40 PVC I would use a Fernco Proflex Coupling. To Tubular brass or, poly the slip joint nut and washer.

    [​IMG]
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,276
    Location:
    Cave Creek, Arizona
    connection

    We use whichever connection is best for the particular installation. You have not told us anything about the actual pipe, other than its size and that is probably a 1 1/2" pipe, rather than 2". But a No-Hub type coupling would be the very last option when all else failed.
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