Bathtub refinishing

Bathtub refinishing also known as bathtub resurfacing, bathtub reglazing or bathtub re-enameling is the process of refreshing the surface of a worn, damaged bathtub to a like-new condition. This process typically involves repairing any damaged areas. Chips or cracks are repaired using Bondo or another type of polyester putty. After repairs are made the surface is prepped with an acid etching. Etching provides mechanical adhesion. Porcelain, enamel, and fiberglass tubs are non-porous and do not provide a good substrate for the new coating to attach to. Etching the surface provides a porous surface that will allow proper adhesion. Another possible method is to apply an adhesion-promoting bonding agent like silane to the surface before applying the coating. The two methods can be used in unison or independently. The greatest adhesion is achieved by using both methods together. Some new refinishing processes do not require the use of etching, by relying on silane alone. After preparing the surface, primer is applied, followed by a top coat. Generally, a catalyzed two-component cross-link synthetic white coating is applied, but the coating does not have the durability or abrasive tolerance of the original glass-enamel coating of a factory-new bathtub.

Coatings used to create a new bathtub finish can be epoxies, urethanes, hybrid polyester-polyurethane, or polymers. These coatings may be rolled, brushed, or sprayed on.

Bathtub refinishing is possible using DIY kits from hardware stores, but some may choose a professional service company offering refinishing services. DIY kits generally do not offer the same level of bonding and thus, deteriorate more quickly, relying primarily on epoxy adhesion. Without professional spray equipment, the final aesthetic look may show brush or roller marks.

...
Wikipedia