joining replacing cast iron with plastic

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Jgaines, Nov 8, 2013.

  1. Jgaines

    Jgaines New Member

    Messages:
    3
    Location:
    Boston
    I've got an old house (~1930) and am redoing the bathroom. There is a lead closet bend connecting to cast iron. I want to replace the lead with plastic, by removing the lead and using a fernco donut to attach the new 4" plastic to the cast iron (the hub of the cast iron is visible at the left in the photo below. But the lead pipe is quite close to the floor level. I don't think there is enough room to put a section of 4" pipe and a 90 degree bend, and not have the bend end above the floor level. Any suggestions for how to do this?
    IMG_5872.jpg

    Also, the 2" line to the sink has a shallow angle between two of the cast iron pieces. In the photo below, you can see that the angle of the left-most cast iron segment is different from the others. I want to remove the cast iron back to the left-most segment, and then put in plastic from that left-most hub. Will the plastic and donut be able to handle this shallow bend?

    IMG_5874.jpg
    Last edited: Nov 8, 2013
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    You could make up some room for the closet bend by using a 4x3 flush bushing in the hub and running 3" from there.

    You cannot insert a pipe into a hub with a donut and expect it to seal if it is not straight. This is the beauty of a lead joint. A 1/16 bend might get you closer.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,233
    Location:
    Cave Creek, Arizona
    You use a "spigot" closet bend which is designed to go in close to the finished floor level. The rubber "donut", if you can get one to fit your hub, is fairly rigid so there is almost not flexibility to it. You will have the same problem with the closet bend because it is also cocked. You need 1/32 bends which are not made in plastic.
    Last edited: Nov 9, 2013
  4. Jgaines

    Jgaines New Member

    Messages:
    3
    Location:
    Boston
    Thanks very much for your replies, cacher_chick and hj. Is there a better way than using the donut (actually a P44U-405 PlumbQuik by Fernco - pictured elsewhere in this forum)? Will it not leak and last long?
  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    If there is room for the fittings you need, I would leave the hub alone and snap the pipe behind the next hub.
  6. Jgaines

    Jgaines New Member

    Messages:
    3
    Location:
    Boston
    I don't think there is enough room. The hub is part of a T. But there is another problem. I took out the lead and cleaned up the hub. The P44U-405 Fernco donut that I bought fits very loosely in the hub. My pipe says Mallory Abendroth AV,WT, 18 lbs ?? FT, and has an XH printed on the hub. So I need a donut that is for connection to XH cast iron. Do these exist?
  7. Reach4

    Reach4 Active Member

    Messages:
    1,872
    Location:
    IL
    I have a friend who converted to overhead sewers a few years ago. The plumbers cut the vertical cast iron, and transitioned it to new PVC (six inch I think) that routed out through the basement wall (core drilled) through a new trench with PVC joining up to what was the only sewer path after winding around the house about 135 degrees.

    Anyway, the somewhat relevant point was that the joint was made by pouring lead into what sure looks like regular PVC. The PVC was on the outside of the cast iron. Maybe I will get a picture some time. I was pretty astonished. I did not see any obvious misalignment. This was not in Chicago, but the plumbers often worked in Chicago.
  8. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    This looks to be a second floor bathroom. Sometimes the best option is to drop into the wall below and make the cut there.

    Using an existing hub, like hj mentions, does not allow for changing the angle. Any pipe inserted into a hub with a rubber bushing will be perfectly straight. A poured lead joint allowed for the crookedness of the layout.
    I would reall think about going further back, and doing a more complete replacement. It may give you a chance to look at the wood structure and it's soundness.
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