How to restore cast-iron bath tubs

Updated February 21, 2017

Cast-iron tubs have been popular since their introduction in the 1880s. Their owners admire the tubs' beauty, stability and resistance to wear. Your tub, however, may be showing its age. With some planning and effort you can restore your tub's finish and its former attractiveness.


Select a work area with very good ventilation, such as outdoors or in a garage. Proper air flow is vital during this project. Protect the work area with plastic sheeting and masking tape.

Turn off the water main and remove the tub's valve and drain. Make sure the tub is completely dry.

Remove or cover the tub's feet. Because of their ornate and detailed design, avoid damaging the feet during this project. If they also need repair or refinishing, send them to a professional.

Enlist the help of family and friends to carefully move the tub to the work area. These tubs can weigh several hundred kg.


Ensure that the tub is completely clean and smooth. Scrape off soap scum and clean with a commercial or homemade cleanser.

Wipe on alkaline emulsifier. Neutralise emulsifier with citric cleanser. Rinse and dry the tub and rub with alcohol.

Repair any dings, nicks, scratches or holes. Trowel fibreglass putty into damaged spots. Wait for the putty to harden. Sand the filled spots, first with coarse paper and then finer paper.

Wipe the tub with a tack cloth.


Use a clean cloth to apply the bonding agent. While the bonding agent sets, put on protective clothing and equipment.

Spray on at least three coats of enamel, drying 10 to 15 minutes between coats. If desired, use a heat lamp to speed up the curing time.

Wet-sand the dried tub with finest paper. Dry the surface with paper towels. Use a power buffer and auto compound to remove any scratches. Hand-buff the tub with car wax.


Clean all clothing, equipment and skin surfaces. Properly dispose of all rubbish and chemical products.

Return the tub to the bathroom. Uncover or replace the tub feet. Reconnect the valve and drain, and turn on the water main.

Allow the refinishing products to cure -- solidify and adhere completely -- for 24 to 48 hours before using the tub.


Professionals with all the right gear and experience can take up to eight hours to complete this project. Do not be discouraged if your efforts take longer. Expect your new finish to remain shiny about a decade, after which time a quick resanding and recoating should give yet another decade or so of good use. To keep your tub looking new, don't use abrasive cleansers or allow mineral deposits to form. Clean the tub regularly to avoid scum build-up.


Cast-iron tubs are heavy. Use proper lifting and carrying techniques to avoid injury. The chemicals used in this project are toxic. Be sure you do not inhale, ingest or come in contact with them. Always wear protective clothing, gloves and masks during the project. Cast-iron tubs may contain lead. Keep children and pets away from the project area, and do not let them inhale or ingest any materials from the project. When properly applied, the enamel finishing is very smooth and slick. Take care to avoid slips and falls when handling and using the tub.

Things You'll Need

  • Plastic sheeting
  • Masking tape
  • Razor blade
  • Alkaline emulsifier
  • Acid-based citric cleanser
  • Denatured alcohol
  • Trowel
  • Fibreglass putty
  • Rotating sander
  • 36-grit sandpaper
  • 80-grit sandpaper
  • Tack cloths
  • Bonding agent for paint
  • Protective clothing -- long trousers, long-sleeved shirt, closed-toe shoes or Tyvek suit
  • Air mask
  • Respirator
  • Gloves
  • Acrylic urethane enamel paint
  • Spray gun, low pressure/high volume type
  • Heat lamp (optional)
  • Paper towels
  • 1,000-grit sandpaper
  • Power buffer with foam pad
  • Auto compound
  • Polymer glaze car wax
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About the Author

Based in Brazos County, Texas, Jennifer Wiginton has been writing and editing since 1989. She has published two cookbooks and articles in “The Joyful Woman” and “The Common Bond.” Wiginton has two degrees and a Certificate in Homeland Security from Texas A&M University.