I need to replace a drain line from an old double cast iron kitchen sink. The existing pipe is 1.5" galvanized steel which threads directly into female threads on a 4" cast iron stack. The male threads of the galvanized pipe broke off in the cast iron.

I'm guessing the easiest solution is to replumb with PVC, How do I attach the PVC to the existing hole in the cast iron?

Hey weekend:

Did you get the male thread out of the female fitting off stack?

If so, then should just need a threaded PVC male adapter, some tefon tape and pvc pipe/fittings/cement/primer, etc. to finish job.

If threads still broken off in cast iron the you will need to get a little creative here. You may just need to take an awl tool and pick away at threads... but most likely you will need to take a sawzall and a bi-metal sawzall blade and just cut the pipe threads to point that cuts threads of pipe, but not threads of cast iron fitting.

Here, you use sawzall to cut just to the point where cut meets threads... slightly less, in fact. Then cut another cut same as last about 1 inch away from other cut. Then take screwdriver and hit it with a hammer to relaeas the piece you just cut out. Because of threads,should just pop out.. then can collapse reat of pipe and teflon up a new male adapter and run pvc from there. Hopefully, that made sense.

Let me know what you think. Did I understand your question.. Talk later... Mark