How to Refinish Porcelain Bathtubs

Old porcelain bathtubs are actually a porcelain coating over cast iron. The cast iron will basically last forever, but the porcelain eventually will get dull, dingy and worn. It's possible to refinish the porcelain surface with special enamel paint that's got polyurethane in it to provide that shiny, shell-like covering that can make an antique tub look new. The process involves dangerous chemicals and should be undertaken only with the proper preparation and safety equipment.

Things You'll Need

• Plastic tarps
• Plastic tape
• Respirator with goggles
• Protective clothing and long rubber gloves
• Hydrofluoric acid
• Brush
• Baking soda
• Paint sprayer
• Porcelain primer
• Enamel paint formulated for porcelain

Instructions

1. Clean the tub thoroughly. Remove all fixtures. Tape plastic tarps all around the exterior of the tub. Cover any part of the tub that isn't porcelain.

2. Put on the protective clothing and respirator. Brush on hydrofluoric acid, using extreme caution (it's corrosive to skin and any nonplastic material). Coat the porcelain completely, letting the acid etch and dull the surface for 15 minutes. Sprinkle baking soda over it to stop the reaction. Rinse and dry the tub.

3. Load your paint sprayer with porcelain primer while still wearing your protective gear. Spray on the primer in a very thin, even coat to avoid streaks or drips, completely covering the porcelain. (The primer should be a different color than the tub to allow you to see when you've got full coverage.) Let it dry for 30 minutes.

4. Reload your paint sprayer with enamel paint formulated for porcelain. Spray it on in the same manner as the primer--in a very light, thin coat. Let it dry for 30 minutes.

5. Apply at least four coats of enamel and as many as six. Let the final coat cure for two days before reinstalling the fixtures and using the tub.

Tips & Warnings

• Ventilate the room at all times.

References

• ThisOldHouse.com: Refinishing a Tub