Removing sink drain from cast iron stack

[Dave]

The drain plumbing on the bath sink is rusted out and needs to go. It is silver colered but don't know what kind of metal it is (standard thin 1 1/4" drain plumbing). It appears to screw inside the female cast iron stack. The connection to the stack looks all built up with scale and rust and am afraid if I take a monkey wrench to the rusted pipe it will crumble or twist into a prezel and not turn. It there a proper tool or way to get this out? Thanks, Dave

[Speedy Jim]

If you are absolutely certain that the TEE fitting in the stack is threaded, my preference is to saw the horiz drain pipe or fitting off as close to the TEE as possible. Then, make a saw cut lengthwise along the horiz pipe/fitting. That will allow you to "collapse" the pipe (with a chisel). Then it will unscrew easily.

It's a bit tricky to sawcut not too deep as to destroy the threads in the TEE.

If the pipe is really badly corroded, you could try driving the chisel into the sides of the pipe. It might collapse without sawing.

This is just general advice; there are dozens of different pipe and fitting combinations you could be dealing with.

Jim