Rusted pipe - need advice
I am helping my brother put new sink cut off vlves on his bathroom. When removing one of the valves, we noticed first that the pipe was iron (tested with a magnet), and second that is was coroded on the bottom so that most of the threads were gone. This is an old beach home built in 1956 and we knowthat the majority of the piping is copper, but we do not know where this iron pipe came from. The other pipe is is good condition.
So how can we repair this pipe? What is it attached to behind the wall? We are hoping that we can vice grip it and unscrew it from whatever coupling is behind it. Does this seem feasable? We want to avoid cutting out the plaster in the bedroom to access the area.