Tying PVC into Cast Iron Drain -- in Los Angeles

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by thebigsee, Jan 29, 2010.

  1. thebigsee

    thebigsee DIY Member

    Messages:
    94
    Location:
    Southern California
    If you go to any hardware store in L.A., seems like all the drain stuff is ABS, and PVC is just for sprinkler systems it seems. I am not sure why that is, but you don't really see PVC on drains around here. Anyone have any idea why this is?

    I want to use a Watco Flexible Waste/Overflow on my tub, but all the fittings on it are Schedule 40 PVC, they don't have an ABS model. I'm going to use it anyways as it's the perfect solution for my tub, but I need to connect it to female threads on a 50-year-old 1-1/2" cast-iron trap. The drain will be pretty much inaccessible once the tub is in place, so I need to glue everything apparently.

    These are my options are far as I can figure:

    1) Screw an ABS nipple into the cast iron, then connect the ABS nipple to the PVC using a banded coupler. Problem is, the drain will be practically inaccessible once the tub is installed, and I am not sure it's OK to have a banded coupler inaccessible as it's not glued.

    2) Screw a PVC nipple into the cast iron (if the threads match, not sure if they do) and then glue the drain assembly onto it. This seems the best solution, but I'm not sure if PVC is OK to connect to cast iron.

    3) Break up the concrete, replace the cast iron trap with a PVC one (if i can find one here in L.A., doubtful) and glue the drain assembly to it. Really not keen on doing this but will if it's the best thing to do.

    Any thoughts? Mainly want to do this right so I don't have leaks and such. Thank you.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,021
    Location:
    Cave Creek, Arizona
    Any of the three methods is okay as long as you do the transition with the proper material. You will NOT find an ABS nipple, but a male IPS adapter and section of pipe will work just as good. All of them require careful measurment unless you can set the tub and then work the drain to it.
  3. dcelite

    dcelite Plumber

    Messages:
    132
    Location:
    Los Gatos, CA
    You can glue the PVC to the ABS. We use Oatey transition solvent weld cement. I guess you may not find that glue at the hardware store. Also, there is no problem with having an approved transition band that is inaccessible. That's how cast iron pipe and fittings are connected.
  4. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    Does your state approve a pvc to abs glue joint?. We do not no matter what glue you use. Have to use either a mission band or male/female fittings only.
  5. thebigsee

    thebigsee DIY Member

    Messages:
    94
    Location:
    Southern California
    Thanks for the input. Ends up that I'm going to have to replace the p-trap (threads too damaged to get an effective seal with either PVC or ABS) with ABS, then connect the ABS to the PVC drain assembly with a banded coupler. That ABS/PVC glue seems far too controversial for me to mess around with!
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