Cast Iron & Galvanized Pipe Rusted Connection

Discussion in 'Shower & bathtub Forum & Blog' started by DIYSEN, Nov 22, 2008.

  1. DIYSEN

    DIYSEN New Member

    Messages:
    2
    Could somebody offer a suggestion on removing a galvanized nipple to a rusted cast iron P trap for a bath tub. Drain system is under a concrete slab. I intend to replace the tub due to corrosion & rust.Is it also possible that the threads on the trap are gone due to corrosion that makes reconnection w/
    new pipe impossible?:confused:
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Squirt it repeatedly with PB Blaster penetrating oil, for about 2 days. You will need a 24" pipe wrench minimum. You still might break something.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,647
    Location:
    Cave Creek, Arizona
    pipe

    How large a hole will he have to make in the slab to get, and turn, a 24" wrench? And what are the chances the trap will snap if he uses that much torque? Cut the nipple out with a SawZall. If you cannot figure out how to do it, call a plumber who does. Your thread in the trap is probably still good. IF not the nipple would have just pulled out or turned easily.
  4. DIYSEN

    DIYSEN New Member

    Messages:
    2
    HJ, JIMBO
    I appreciate your help & thanks.Will pre heating the connection w/ propane
    torch help loosen fittings & where could I get the PB blaster penetrating oil
    since this is my first time hearing this type of oil. I know of WD40.
    Thanks again.
  5. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    PB blaster is pretty common. WD40 helps, but is not a true penetrating oil, although it is often used as such.

    Heat on the trap might help, but hj's point about just cutting it and joining new with banded couplings makes sense also.
  6. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,350
    Location:
    Yakima WA
    PB Blaster is available at most hardware stores. It is better at penetrating than WD 40, but I concur with the suggestion about the recip saw and banded coupler option being the better option.
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