The shower doesn't go to a P-trap; it goes to an old cannister trap that is under the floorboards (or was, until I removed them). The cap is a 5" metal disk with a 1.25" hex-nut shaped protrusion in the center. The trap itself appears to be lead, and the incoming and outgoing pipes in it are lead as well. They go under the tub (which isn't part of my remodeling plans) so I want to just remove the cap and replace it with a flush cap so I can tile around it, and leave it as-is.
The problem is when I torque it with my plumbing wrench (with enough force to leave teeth marks on the hex nut) the only movement I get is the input and output lead pipes twisting slightly. Not a good idea. So my next thought was to heat the top of the trap a little (like running a jar under hot water to loosen the lid), but I'm afraid I'll just melt the lead and be completely in trouble.
Does anyone have experience with these old traps, especially stuck ones, that could give me any suggestions on how to safely remove the cap?
Many. many thanks Keith