While demoing a bathroom, I discovered that the waste system is copper. While removing the rotten subfloor I had to cut the flange off the 3″ copper. (It was soldered and I didn’t like the idea of open flame over a working waste system.) I was planning on cutting back the toilet bend a bit and connecting a short piece of ABS pipe with a fernco hub, to which I can attach a standard toilet flange. Will that work? (I suspect I’ll have a similar issue with the shower drain.)
Just saw online a pvc closet flange that fits inside a cast iron toilet bend and has a gasket that compresses to the inside of the cast iron. I don’t know what they’re called. Is there such a thing for copper?