Reglazing a bathtub is a professional project which involves etching the old surface, using a chemical compound that is 'hot' enough to melt soap residue and oils away. In saying 'hot' I don't mean temperature wise. It is more of strength. It will be a chemical solution that not only melts away residue but also leaves absolutely no residue behind.
Now that the Bathtub, tile or shower has been etched it will receive a molecular bonding agent that is hand rubbed into the pores caused by the etching process. Now will be systematic application of synthetic porcelain and a separate application of molecular bonding agent. The set time on each of these depends on the temperature and humidity level. It will also depend on the surface being refinished. Each surface is able to have a customized solution of synthetic porcelain. Porcelain and ceramic surfaces will do much better with a liquid glass additive. While acrylic, fiberglass and cultured marble (which is actually fiberglass resin and crushed limestone) will do better with a fiberglass resin to melt into the old surface then a synthetic porcelain finish coat fused into that. The entire process of bathtub, tile and shower reglazing is to make the new surface an integral part of the old. We literally want the two to become one.
So what is Bathtub Painting?
Epoxy paint is very old technology and was actually used in the 1990's for Apartment and Motel bathtub painting. It has a dull 'painted' look to it and it also will yellow when bleach is used on the painted fixture.