Cast Iron Sewer Pipe Repair Paste. You then apply the epoxy putty by pushing it into the hole or crack in the pipe. Then, wrap the wet bandage around the pipe and putty, extending the bandage a bit beyond the putty on each side.

Clean the repair area by removing rust with a wire brush and dusting away debris with a clean rag. You then apply the epoxy putty by pushing it into the hole or crack in the pipe. If you have a small section of visible cast iron drain pipe with a leak or crack, you may repair the pipe yourself.