(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 8 of 8

Thread: joining replacing cast iron with plastic

  1. #1
    DIY Junior Member Jgaines's Avatar
    Join Date
    Nov 2013
    Location
    Boston
    Posts
    3

    Default joining replacing cast iron with plastic

    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?
    Name:  IMG_5872.jpg
Views: 211
Size:  66.7 KB

    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?

    Name:  IMG_5874.jpg
Views: 189
Size:  83.4 KB
    Last edited by Jgaines; 11-08-2013 at 06:36 PM. Reason: rewording

  2. #2
    Test, Don't Guess! cacher_chick's Avatar
    Join Date
    Jan 2008
    Location
    Land of Cheese
    Posts
    3,161

    Default

    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. #3
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,687

    Default

    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 by hj; 11-09-2013 at 07:35 AM.
    Licensed residential and commercial plumber

  4. #4
    DIY Junior Member Jgaines's Avatar
    Join Date
    Nov 2013
    Location
    Boston
    Posts
    3

    Default

    Quote Originally Posted by hj View Post
    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.
    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. #5
    Test, Don't Guess! cacher_chick's Avatar
    Join Date
    Jan 2008
    Location
    Land of Cheese
    Posts
    3,161

    Default

    If there is room for the fittings you need, I would leave the hub alone and snap the pipe behind the next hub.

  6. #6
    DIY Junior Member Jgaines's Avatar
    Join Date
    Nov 2013
    Location
    Boston
    Posts
    3

    Default

    Quote Originally Posted by cacher_chick View Post
    If there is room for the fittings you need, I would leave the hub alone and snap the pipe behind the next hub.
    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. #7
    DIY Senior Member Reach4's Avatar
    Join Date
    Sep 2013
    Location
    IL
    Posts
    1,285

    Default

    Quote Originally Posted by cacher_chick View Post
    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.
    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. #8
    Forum Admin, Expert Plumber Terry's Avatar
    Join Date
    Aug 2004
    Location
    Bothell, Washington
    Posts
    14,221
    Blog Entries
    1

    Default

    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.

Similar Threads

  1. replacing cast iron sewer with plastic
    By switchex in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 33
    Last Post: 01-14-2013, 12:00 PM
  2. Replacing Cast Iron Shower Drain / P-Trap & Replacing with ABS
    By n0teye in forum Shower & bathtub Forum & Blog
    Replies: 2
    Last Post: 08-29-2011, 02:36 PM
  3. Plastic To Cast Iron Pipe
    By Barkri12 in forum Toilet Forum discussions
    Replies: 1
    Last Post: 06-04-2009, 12:43 AM
  4. Iron Cast vs Plastic pipes
    By Lee5929 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 07-23-2006, 05:34 PM
  5. Cast Iron: Cutting and joining to PVC
    By remodelingit in forum Remodel Forum & Blog
    Replies: 8
    Last Post: 06-22-2005, 06:31 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •