a friend of mine asked me about repairing a 2inch round hole on a pipe for a fire sprinkler system in a warehouse. He says the pipe is around 3/16 thick.. there is no pressure or water in the pipe now... he has a 90amp flux core welder from harbor freight. can i actually cut a section of new pipe and put it over the hole and weld it? I'm a certified welder but not for pipe. (not yet at least)