Scrub the metal shower with a trisodium phosphate cleanser and a plastic brush or coarse sponge. Rinse the metal and wait three to four hours for the entire shower to dry.
Cover portions of the shower you do not want painted with masking paper and painter's tape.
Coat the clean metal shower with galvanized metal etching primer, using a roller, equipped with a shed-free cover. Promote a slick finish by smoothing the wet etching primer, using a 3-inch polyester paintbrush. Apply light pressure and brush with long vertical strokes. Wait four hours for the shower to dry.
Wash the polyester paintbrush and roller with water.
Stock the roller frame with a new cover. Coat the primed metal shower with a two-part appliance epoxy, using the roller. Apply the epoxy paint as you did the primer. Wait 24 hours for the final finish to dry and cure.