Sanding a bathtub

[Michael Weber]

I know they can be refinished (lose long term durability)or have an insert made (expensive).
I have a very old cast iron porcelain tub that in good condition except that the finish is rough which makes it difficult if not impossible to clean well. Looks a bit grungy after much scouring. It has no chips or cracks or rust. Since its old and probably has a thick layer of porcelain I was thinking of sanding with my ROS using very high grit paper. I know it's available up to 6000 grit at least. Is the worth a try or is it a disaster in waiting? Not sure what my starting and finishing grits should be. Anyone attempt this or have advice?

[Steve Peterson]

Is the original surface rough? Or is there a layer of hard water build-up sitting on top of the surface? I would try the remedies for removing calcium build up before attacking the porcelain surface.

Steve

[Michael Weber]

Well, I'm very embarrassed. I actually ask this question here a couple of years ago. Found it when I googled it this morning. Jeez, it's a good thing I still have a sense of humor because all the rest of them,including memory, are totally shot. Too late to delete. Sorry

[roger wiegand]

I'm with Steve, try a lime remover first. Porcelain on cast iron is a glass surface, both very tough to roughen and going to also be hard to smooth. Rather than a sander I'd be looking at a glass polishing agent like cerium oxide (available on Amazon) used with a polishing pad on a ROS-- try it by hand in an inconspicuous area first.