Changing a copper connecter to a cast iron stack

[nhilo32]

I have sink drain that is a copper pipe leading to a cast iron stack. The copper pipe is leaking about half an inch before it goes into the stack. I need to change the copper pipe. There appears to be a pipe connector screwed into the side of the stack however I CANNOT unscrew it for the life of me. I've tried soaking it with WD40 and letting that sit. I've banged on it with a hammer (might have been a little more gentle here than necessary as I didn't want to crack the stack). I've tried heating it with a MAP gas torch. It will not budge. How do I twist this thing out? Is that even the best thing to do?

 

[havasu]

Your first step is to toss the WD-40 (water displacement) and get a can of PB Blaster, which is made to penetrate. Let it soak overnight, then give it another shot. Also, post a picture so the folks in here can confirm this is the correct way to do it.

 

[johnjh2o]

Don't hit it with a hammer you could crack the cast iron. (big no no) Cut the copper pipe off as close to the fitting in the cast iron as possible. Using a hacksaw blade make two cuts on the inside of brass fitting a 1/2" apart. Being careful not to cut into the threads in the cast iron fitting. (take your time) After you have made the two cuts pick out the small section of brass. (it must be removed the entire length of the fitting) Then using channel lock pliers collapse the fitting by squeezing it. At that point it will turnout very easy.
John

 

[LiQuId]

What john said. and then re connect with a Mj coupling, make sure its a copper to Ci coupler. ( after replacing the leaking section )

 

[nhilo32]

havasu I will try that.Also I read somewhere else that a 1:1 ratio of transmission fluid and acetone is up to 4 times as effective. If either works I'll post it.

John, if that doesn't work I'll try your method.

Liquid, Since I have all the floor boards up (this is part of a bathroom remodel), I'm going to replace the whole line with plastic.

Thanks, everyone for your comments. I'll let you guys know how it turned out. Not looking forward to cutting it out if that is what has to happen.

 

[nhilo32]

Here are some pictures of what I'm talking about.

 

[johnjh2o]

It looks like it's in a fairly easy spot to cut it out. If that copper is marked DWV I would remove as much of it as you can. DWV copper had yellow lettering on it.

John

 

[nhilo32]

I'm going to take the whole line out and replace it with plastic. I was wondering if the section of pipe that has six sides on it is actually able to be unscrewed. It looks like it should be, why else would it have a six sided shape, but I'm starting to wonder. Maybe whoever did this sweated the copper into it.

 

[havasu]

It does almost look like it has been sweated. if you plan on replacing the entire section with plastic (ABS), I would have everything ready and get a big ol' pipe wrench with an extension pipe and go to town. it just might unscrew. If it doesn't, you will be prepared to replace it anyway. Keep us informed of the progress.

 

[johnjh2o]

The fitting that is screwed into the cast iron is called a solder bushing. They were very common back in the day. Unless your planning to replace the cast iron side outlet ell don't use to much force on the bushing.

John

 

[nhilo32]

Up till now I have been trying to unscrew the bushing, without much luck either. Would it be better to remove the copper from the fitting and sweat in a new copper section and then move to plastic with a Fernco fitting or remove the solder bushing? If I remove the solder bushing what is the best thing to replace the bushing with to convert the sink line to PVC?

 

[johnjh2o]

You would be far better off to remove the bushing and use a PVC male in it's place. It's not that hard to do. I have replaced many of them with the method I described to you in much tighter locations then you have.

John

 

[nhilo32]

Up till now I have been trying to unscrew the bushing, without much luck either. Would it be better to remove the copper from the fitting and sweat in a new copper section and then move to plastic with a Fernco fitting or remove the solder bushing? If I remove the solder bushing what is the best thing to replace the bushing with to convert the sink line to PVC?

 

[mccmech]

If you want to unthread the brass/copper adaptor which is threaded into the cast iron I would suggest heating up the cast iron female threads. Metal expands when it is heated, therefore heating the copper/brass adaptor will only make it tougher to unthread. Heat the female threads & be amazed at how easily the adaptor unthreads. Just my .02 worth

 

[nhilo32]

Wow. That was kinda rough. I tried heating it a couple more times, just in case, to no avail. Then tried John method. That worked! Thought it did not crush with a channel lock, I had to use a screw vice. However, John, I did cut into the threads a bit. Do you have any advice on what to do in that situation. It does not appear to be a deep cut, I don't think it even went all the way through the threads. I'm hoping your going to tell me there is some kind of putty I can use when I screw in the male PVC bushing. Any suggestions?

 

[desertwater]

Teflon tape and pipe dope

 

[johnjh2o]

If the cut isn't to deep just use T tape with pipe dope over it. It may be a good idea to run a galvanized nipple in and out of the taping a couple of times to clean it up before installing your PVC male.

John

 

[LiQuId]

I have a question for you john.

-Where Can a buy a winning Set for life Lotto ticket in canada ?

..you are very wise, and a Credit to this forum.

 

[johnjh2o]

Liquid I have a better idea when I win I'll tell you were I got my ticket.

John
Thanks for the complement, but there are many plumbers on this forum that are well qualified.

 

[LiQuId]

there are indeed and its soo refreshing now that........ naw.. I wont go there