What kind of drain pipe is this? How can I best transition to PVC?

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brian717

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Hi fellas,

A pipe running from my tub was leaking so I went to take a look at the culprit, and found 1 and 1/2 inch threaded metal pipe feeding into a 2" cast iron vertical stack:

This is the pipe after I pulled it out:

http://imgur.com/K40Hqm0
http://imgur.com/8YUELtn

... and here is where it was connected to to the stack (the threaded 45 degree fitting there connects to another metal nipple that connects to the threaded hub in the stack):

http://imgur.com/9dWZ0l0

The plumbing elsewhere in the house is PVC connected to cast iron vertical stacks, so I'd like to do the same thing here. What is the best way to transition from that metal threaded hub to PVC?

Thanks for your help!
 

Cacher_Chick

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Hard to judge size in the photo, but me thinks you need a 1-1/2" male threaded adaptor to run a new piece of PVC pipe to the tub.
 

brian717

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Yup, it's 1-1/2". Can I just screw PVC into the fitting? I've heard that plastic could crack in a metal tapped fitting.
 

Jadnashua

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A male pvc thread usually is okay, what you don't want is a female fitting for longevity. It's possible it could break, but it's more common for a female socket to eventually split.
 

Tom Sawyer

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It's either that or invest in an 1-1/2" not pipe tap which will set you back a few dollars.
 

brian717

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An update:

First off, thanks for all the help. Due to the limited space there, I tried my best to clean up the threads in the fitting and got a threaded PVC adapter in there with some thread sealant. Unfortunately, as hj predicted, this still leaked. The 45 degree fitting is connected to a nipple that screws into the tapped cast iron hub. The nipple looks yellowish - I'm assuming it's brass? Have brass nipples ever been used in DWV systems?

I tried to fit a 24" pipe wrench in there to remove the 45. Not enough space to get a grip on it. My 18 incher didn't fit enough to get any real torque on the fitting, either. So - if I cut the 45 off, would I be able to use a banded coupling to join PVC to the threaded brass (I assume it's brass)? I feel like the threads would stop it from making a good seal, but what do you all think?

Thanks again for all the help.
 

Terry

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Cut off the pipe where there are no threads, use a banded coupling either into a 45, or a street 45.
There is no way I would bother with a wrench on that. Just cut that bad boy off. :)
 

brian717

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Cut off the pipe where there are no threads, use a banded coupling either into a 45, or a street 45.
There is no way I would bother with a wrench on that. Just cut that bad boy off. :)

... I just checked it out, hoping to do just that. Looks like the whole thing is threaded from the 45 all the way into the tapped hub (it's only about 2 inches besides where it's screwed into the 45 and the hub). I wish I had gotten a picture. I guess this means I need to go back to the wrench?
 

Cacher_Chick

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I cannot see what is in that insulation, but I would work hard to clean up those threads and put in a brass nipple with some pipe dope and work out from there.
 

Tom Sawyer

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Ok, so cut the 45 off. Carefully slice the remaining pipe lengthwise into the tee, cold chisel and hammer the piece out, clean up the threads and screw a male adapter in.
 
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