A cast iron bathtub can be a charming addition to your bathroom provided it is in good condition and properly maintained. Antique clawfoot tubs are generally made of cast iron and prone to rust if they have not been properly treated. A few coats of high quality primer and paint can help restore the appearance of your cast iron bathtub, help prevent future damage and extend the life of the tub.
Sand the outside of the tub using 150-grit sandpaper. Continue to sand until all flaking paint is removed.
Apply an oil-based, rust resistant primer, such as Rust-Oleum, to the cast iron bathtub. The primer will help the paint properly adhere to the cast iron surface and prevent rust that can damage your tub.
Allow the first coat of primer to dry and apply a second coat of primer. Let the primer dry completely before you continue painting the bathtub.
Paint the cast iron tub with an oil-based enamel paint in your desired colour. Allow the paint to dry completely.
Wet a piece of 220-grit wet/dry sandpaper. Gently sand the dry enamel paint with the wet sandpaper to create a smooth surface. Wipe away any excess water with a dry cloth when you are finished sanding.
Apply a second coat of the enamel paint to the tub and allow it to dry completely. Repeat the wet sanding and wipe the tub clean to finish the job.