joining replacing cast iron with plastic

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Jgaines

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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
 
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Cacher_Chick

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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.
 

hj

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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.
 
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Jgaines

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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?
 

Cacher_Chick

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

Jgaines

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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?
 

Reach4

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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.
 

Terry

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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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