Before you attempt to refinish a steel bathtub, understand a few important points. Since steel is ill-suited for adhesion, it requires abrasion, or it will ultimately shed its new finish. Unfortunately, steel is too durable for the same friction-based abrasion techniques used to prepare surfaces like vinyl, plastic and fiberglass. Apply a special type of primer, capable of etching metal. In addition, choose a durable coating that will stand up to a relatively large amount of duress.
Wash the steel bathtub with a water-based degreaser, using a coarse plastic brush. Rinse the bathtub with wet rags. Wait two to four hours for the tub to dry.
Cover portions of the steel bathtub you do not want painted with professional painter's tape. Cover the floor beneath the bathtub with heavy-duty fabric dropcloths.
Apply galvanized metal etching primer to the clean steel bathtub, using a paintbrush manufactured for use with latex paint. Wait six hours for the primed bathtub to cure.
Wash the galvanized metal etching primer from the brush with warm water.
Apply epoxy appliance paint to the primed steel bathtub, using the clean paintbrush. Wait 24 hours before using the tub.
Never prime a dirty steel bathtub, or the finish will fail
Never paint a bare steel tub, or the paint will peel.
Do not use an ordinary acrylic latex or oil-based primer on steel, or the finish will fail.
Do not use an ordinary acrylic latex or oil-based paint on a steel bathtub, or the finish will ultimately chip or peel.