I am fitting a new WC to a 1960s vintage soil pipe. The pipe is cast iron and joined with lead which appears to have been cast in place (not foil wrap). I want to remove the last 'extension' piece (about 4" long) which will leave the remaning 'female' pipe at pretty much the exact correct height for my new WC.
The advice in the previous discussion was to dig out the lead bit by bit and to wiggle the pipe by hand working it loose. A 1/4" wood chisel (old) was suggested as a good tool for the job.
My question is: why is it not possible to undo this by putting a blowtorch on the cast iron pipe that is to be removed and to heat it until the lead melts? Is there a danger of explosion? a nager of cracking athe iron of the bit I want to retain?
Has anyone 'dug out' lead from such a joint? Can it really be done in a reasinable length of time? Would a plumber do it that way?