How To Cut Cast Iron Pipe From Inside. (drill not included.) used to cut off pipes below floor level or in the ceiling in new construction, around pools, and for replacement of closet flanges. A chalk mark is drawn around the pipe.
A snap cutter, a reciprocating saw, or a grinder. A sthil saw with a 300mm blade might nearly do it.
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An angle grinder with a metal blade will cut most of it, you need access all around the pipe. Applying a pipe repair bandage over the repaired part of the cast iron pipe is the final step to this process.