I have a old sink drain (it was a double sink but converted to a single bowl in the early 70's). There is a threaded stub sticking out of the wall that connects back to (what appears to be a cast elbow). I've tried penetrating oil to get the stub loose (I want to cap it off back flush with the wall) and I haven't had much success in loosening the threaded pipe. I was wondering if I should continue trying the penetrating oil method or can I use heat and possibly get the pipe to "break free". The pipe looks like it's steel and I think the elbow is cast so I am afraid to use much pressure for fear I will break the pipe and have a bigger problem than I already have.

I only found this situation when I pulled an old dishwasher out to replace it and the new one won't fit with this pipe sticking out!

Thanks for any help.

I would not do much hammering on the pipe in the wall or the pipe sticking out. The pipe in the wall is probably cast iron and is very easy to break. Here is the way I would do it but remember I am talking about the situation one that I can get to all the things I need to. First I would use a "Jab" saw and I would saw the pipe sticking out off flush with the cast iron pipe, then I would use a hack saw blade or the "Jab" saw to saw into the threads of the pipe that is left in the cast iron. Make two cuts side by side about one half inch apart, saw just deep enough to weaken the threads. When you have cut the pipe use a screwdriver or small chisel to knock out the small piece of iron that is left between you two cuts. When you get that out you will be able to use the chisel to remove the rest. Then use a plug with lots of pipe dope.

The wall stubout is no doubt galavanized iron and not cast iron. This galvanized nipple will screw into a threaded elbo inside the wall. What you must do is unscrew the galvanized nipple from the threaded elbo and replace it with a galvanized plug. Don't forget to teflon tape the threads. Good luck, Tom

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Originally Posted by speedball1

The wall stubout is no doubt galavanized iron and not cast iron. This galvanized nipple will screw into a threaded elbo inside the wall. What you must do is unscrew the galvanized nipple from the threaded elbo and replace it with a galvanized plug. Don't forget to teflon tape the threads. Good luck, Tom

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Tom:

I agree, it is galvanized and I was wondering if heat would be OK to use or should I stick with the penetrating oil. The elbow looks like cast.

Bill

The elbo could very well be cast iron. You may try heating the elbo or tapping on the nipple to loosen the threads. Put a 14 or 18" pipe wrench and turn the nipple out counterclockwise. Good luck, Tom

Quote:

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Originally Posted by speedball1

The elbo could very well be cast iron. You may try heating the elbo or tapping on the nipple to loosen the threads. Put a 14 or 18" pipe wrench and turn the nipple out counterclockwise. Good luck, Tom

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Well, I tried that for quite a while, but finally had to resort to cutting the pipe flush with the wall and capping it off. Thanks for all your help!!

:)