I am replacing a garbage disposal unit in the kitchen. Everything is off but the flange, and I am getting very frustrated. I need to replace the sink flange as it doesn't fit the new unit I'm replacing the old unit with. But ... I cannot get the sink flange to loosen up, the plumbers putty is being very stubborn. Is there any way I can get that flange to come off without damaging the sink? Thanks for your time.
I had good luck removing a stubborn strainer once with a propane torch, heating the flange portion that sticks below the sink, then tapping at it occasionally with a hammer.
If you use a mapp gas torch, be aware that sucker will heat up fast. Try to stick to propane if you don't use mapp torches much.
Also, keep a close eye on things. You may not be fighting plumbers putty at all. Might be silicone in there from a past repair, or diy install.