I looking to cut old cast waste pipe and replace the removed portion with PVC waste hopefully connecting the two with a fernco fitting.

What type of blade do you use? Will a sawsall work? Any input would be great. Tim

You would need a metal cutting blade. I don't know if an all purpose blade would work or not. I used a hack saw when I did this before by hand. The fitting worked for me. I do not know any codes and am not an expert.

Most any good reciprocating saw will do the job but it with take more time than you might imagine. Since you are removing a section you're going to make two cuts. I would suggest you call Home Depot or a tool rental place and look into a cast iron pipe cutter, looks like a big ratchet chain with cutter wheels.

A friend of mine also said that cast iron might crack if not using a slow setting on a variable speed saw. Just thought I'd pass it along.