Wrong answers!!!
If you do not know the process of refinishing, you really should not answer the question. Failed refinishing jobs on most occasions are the process of DIY products and or a person that has no clue of what they are doing. The process is an actual reglazing and not a painting of the tub. It is not porcelain it is an areospace epoxy much like what is found on the space shuttle (not the parts that keep falling off either
).
Re-pocelaining the inside of a tub is not an option as porcelain is applied and then baked at 2500 degrees.
Clawfoot tubs should go through this process:
Sandblasting the outside after all plumbing parts are taken off. Next you should start with 360 grit sandpaper and an orbital sander and sand outside of the tub, then 300 all the way to you get to 220. The exterior finish only looks textured due to the pitted cast iron. This process will take care of it and it will smooth the outside of the tub. Next the tubs best exterior finish is not expoxy and you should never clean the tub with water nor use stripper on the outside of the tub. The best possible finish is POWDER COATING. This is the same process that is on the outside of semi and truck rims and you know how much abuse those take.
The interior of the tubs get cleaned 100%, the washed again with an idustrial cleaner and followed by an etching process. This prepares the porcelain and opens the pores of the tub for a new finish. Then there is 3 coats of aerospace primer followed by 3 coats areospace HSLD topcoat. The process then needs 24 hours to cure. The finish is new and I dont know about the rest of refinishers but I give a 5 year written warranty.