Replacing Sink Drain/ Sanitary T

[AKS14]

I have the wall opened up in my bathroom and I have what appears to be a 2" cast iron vent with a T and a 1.5" copper sink drain tied into it.
I was originally planning on just removing the copper sink drain and replacing it with PVC threaded into the cast iron T, but the position of the fitting being directly in the middle of a stud makes it a bit difficult to get a wrench on and also when I did, it didnt seem to budge even when putting some considerable force on it. I could heat it with a torch but the area is pretty tight and I dont want to damage anything, also I am not sure if I do remove it the threads in the T will be in good shape or not

I was thinking of just cutting a few inches above and below the T, and going with reinforced fernco couplers to integrate a PVC T

So I was thinking of adding a bit of blocking up towards the ceiling to fit a support bracket to the pipe, then taking a sawzaw with a metal blade to cut the pipe (is this a good idea or bad?), then going back and perhaps cleaning up the outside of the pipe with a bit of sandpaper and fitting a PVC "all hub" T with some stubs of PVC glued into it, and fit it in place with reinforced fernco couplers. Would I need to add any sealant on the outside of the cast iron pipe before putting the fernco on to insure there arent any leaks, or is just thoroughly cleaning/sanding/deburring the pipe good enough? Also what would be the best way to transition from the 2" outlet to a 1.5" for the sink drain, just a glued in fitting?

Attached is an image of what I am working with, the vertical pipe measures out to about 60mm OD (which appears to be 2" cast iron) and then the horizontal sink drain measures out a bit over 40mm OD (which appears to be 1.5" copper)

Thanks in advance.

 

[Reach4]

"So I was thinking of adding a bit of blocking up towards the ceiling to fit a support bracket to the pipe,"
For your searching term, you would be using a "riser clamp" and some carpentry.

"Would I need to add any sealant on the outside of the cast iron pipe before putting the fernco on to insure there arent any leaks, or is just thoroughly cleaning/sanding/deburring the pipe good enough? "
Usually, you use liquid dish washing detergent as a lube.

"Also what would be the best way to transition from the 2" outlet to a 1.5" for the sink drain, just a glued in fitting?"
The thing that makes that transition is called a trap adapter.

"I was originally planning on just removing the copper sink drain and replacing it with PVC threaded into the cast iron T, but the position of the fitting being directly in the middle of a stud makes it a bit difficult to get a wrench on and also when I did, it didnt seem to budge even when putting some considerable force on it. I could heat it with a torch but the area is pretty tight and I dont want to damage anything, also I am not sure if I do remove it the threads in the T will be in good shape or not"
I see the access is very very restricted. Could you pull that metal thing away, move the electrical wire, and carve up that stud more? That would simplify things in that you would not have to change out the cast iron. I am not a pro.

After carving, you could sister a piece of wood with a hole in it to the carved-up stud. Then screw and glue the new wood to the old.

It is possible to get a piece of threaded schedule 80 PVC, rather than schedule 40 with the glue-on adapter. That would reduce the diameter going thru the holes in the wood.

BUT WAIT: can you use the right banded coupling and feed that copper pipe with PVC? Is the copper leaking or something?

 

[Sponsor]

 

[AKS14]

"So I was thinking of adding a bit of blocking up towards the ceiling to fit a support bracket to the pipe,"
For your searching term, you would be using a "riser clamp" and some carpentry.

"Would I need to add any sealant on the outside of the cast iron pipe before putting the fernco on to insure there arent any leaks, or is just thoroughly cleaning/sanding/deburring the pipe good enough? "
Usually, you use liquid dish washing detergent as a lube.

"Also what would be the best way to transition from the 2" outlet to a 1.5" for the sink drain, just a glued in fitting?"
The thing that makes that transition is called a trap adapter.

"I was originally planning on just removing the copper sink drain and replacing it with PVC threaded into the cast iron T, but the position of the fitting being directly in the middle of a stud makes it a bit difficult to get a wrench on and also when I did, it didnt seem to budge even when putting some considerable force on it. I could heat it with a torch but the area is pretty tight and I dont want to damage anything, also I am not sure if I do remove it the threads in the T will be in good shape or not"
I see the access is very very restricted. Could you pull that metal thing away, move the electrical wire, and carve up that stud more? That would simplify things in that you would not have to change out the cast iron. I am not a pro.

After carving, you could sister a piece of wood with a hole in it to the carved-up stud. Then screw and glue the new wood to the old.

It is possible to get a piece of threaded schedule 80 PVC, rather than schedule 40 with the glue-on adapter. That would reduce the diameter going thru the holes in the wood.

BUT WAIT: can you use the right banded coupling and feed that copper pipe with PVC? Is the copper leaking or something?

So generally no sort of adhesive or serious prep of the cast iron pipe is needed to get a good seal with the Ferncos?

And I was trying to avoid carving that stud up even more, and I don’t think the extra room would particularly make it easier to get that fitting loose. I was able to get a fairly good grip on it but being 60 years old I think it’s just pretty well stuck in there.

Plus I think from spending time lurking these forums the common sentiment among people is to get rid of the cast iron Ts because they are prone to leaking/failure once they get old like mine.

The copper sink drain isn’t leaking but I just feel like it may be one of those things where I finish my new bathroom and 1-2 years down the road it leaks there and I’m kicking myself in the ass for not spending an hour and $50 worth of parts to just fit up all new PVC