Crumbled bathtub drain flange
 

Hi,

I've got a pretty big problem with this bath tub. The ring was completely corroded and the cross in the middle was gone. So I used an internal wrench to try and screw it out and the whole thing just crumbled, leaving me with a ring of the old flange attached to the inside of the piping (image). Its extremely stubborn and theres a lot of old plumbers putty sticking it to the threading.

Any ideas on how I could chip this away and clean off the putty or get off the old drain flange altogether would be greatly appreciated.

Thanks!

Hope you have solved this by now?

Weaken the bond by making cuts in the flange using a small abrasive cutting disk with arbor in an electric drill.
Also, torqueing it in the direction of tightening it sometimes cracks it loose, either with a wrench or by using a hammer and chisel to deliver impacts.

And try a torch.

If he could get under it to use a wrench, he may as well replace it.

Or maybe go in through an access panel.