Cast iron tubs add vintage charm to any bathroom. The tubs are made from iron with a porcelain or enamel layer on top, and this top layer must be maintained and repaired. If it is not, the porcelain or enamel will become cracked, worn and stained. You can repair and restore shine to a cast iron tub, and if properly maintained, it can last a lifetime.
Protect the walls and floors with a protective cover. Use plastic sheet, bin bags or old towels and blankets (for the floor). Cover the legs of the tub if it differs in material. Vintage clawfoot tubs, for example, have metal legs and need to be protected.
Use a razor to remove the old caulk from around the edges of the bathtub and the closest surrounding tiles.
Clean the bath with a commercial-grade bathtub cleaner. Sprinkle the tub with the cleaner, let it sit for five minutes and then scrub the tub until it is clean.
Use a scrubbing brush to apply acid etching paste or sealer to the tub. This should fill in the cracks, scratches and chips in the tub. Let this rest for 15 minutes before filling the tub with warm water and cleaning the tub again.
Apply a coat of primer thoroughly to the entire bath tub. Then let it dry for a few minutes.
Apply a top coat of specialist enamel or porcelain paint to the entire bath tub. Wait until the tub has dried fully.
Apply another coat of glaze or gloss enhancer to the tub, and let it dry.
Protect yourself by wearing a mask, goggles and a protective cover to your body (or old clothes).
If the tub has claw feet for legs, add primer and paint the legs silver or gold, and then apply a top coat of gloss.
Make sure the bathroom gets plenty of ventilation so that you are not overwhelmed with the smells of commercial-grade cleaners.