Well, this sure escalated.

After changing out the supply lines, replacing the stems and washers in the shutoff valves, and replacing the p-trap pipes -- everything was crusty and drippy -- I decided to go with a new faucet as the valves were dripping underneath and I didn't want to go through the chore of tracking down parts for an off-brand faucet.

This has opened up another potential problem. After removing the old drain, I can't get the new bottom drain gasket to seat propertly in the sink hole. I suspect the chip circled below is the culprit. The old gasket has a bulge in it where it was seated into the chip, but the new gasket isn't conforming.

Short of replacing the sink, any thoughts on how I can get a good seal on this? Should I pack a little bit of plumber's putty in there? Any other suggestions?

Sink drain hole:



Gasket Bulge:



I tried using the old gasket but keeping the bulge in the exact location while snugging it up is proving to be difficult. The old drain was brass and the nut holding it was extremely tight. Much tighter than I can get the plastic nut on the new drain.

I hope you enjoy plumbing more than I do.

Ha. I don't mind it, actually. It only sucks when unexpected things happen, which with this old house, seems to be every step of the way. 

A new gasket and silicone sealant. 

I've had great success in similar situations with EPDM sealant. If you want the gasket to be removable, just "fill" the dent (after thoroughly cleaning and degreasing it) and let it dry for about 24 hours. It won't stick anymore after that, but it will still be more flexible than it is when hardened completely.

I went with the Oatey putty. Works great, very easy to press and shape. Lightly sanded after an hour. The lip line has a slight wave in it, but I think the washer will seat against it without any issues. Of course, the OCD in me wants to keep sanding and feathering the perimeter of the patch, but I think I'll have to be like Elsa on this one. (If you have small kids, you'll get it)

Glad it worked, I usually sing that before I post something however it only works half the time.