OK, here’s a weird one.

I was given a 1931 Standard double-bowl kitchen sink for my soon-to-be-renovated kitchen in my 1930 house. Great sink. Cast iron, white porcelain surface. Problem: One of the bowls (the deeper one) has some weird bumps on it. It looks like someone filled up the basin about four inches with some chemical and it damaged the porcelain surface. Little bumps everywhere. The rest of the sink is smooth and in good shape. I’ve look everywhere for a reporcelaining shop, and there’s only one place in the midwest that does it, so I’ll probably have it reglazed. I know this isn’t the best option, but I’m a sucker for old plumbing. My question: any ideas on how to remove these bumps? I’ve tried a wire wheel on my drill — it brought down the bumps a bit to make the surface a little smoother, but it also generated a lot of white dust. I wonder if this is water scale? I tried soaking towels in vinegar and placing them on the surface of the sink for a few hours — nothing. So I guess my question is this: if I get some serious sandpaper and smooth out the bowl (likely bringing the surface down to the cast iron underneath) will the glazing guy still be able to get a relatively smooth surface? Thanks for any advice.

Mike