work with metal all day, and have cut pipes before. jake said it Chop saw is the way to go with pipes wrapped in tape.Just need a smooth half round file for the bur. Problem with sawzall is they have a tendency to bounce if your not pressed up to the pipe. Bandsaw is next best just go slow. If your pipe does discolor which i doubt unless you have a really dull blade a small buffer wheel will take it right out. Good luck
