How to Refinish a Cast Iron Tub
Cast iron tubs are built to last ā but the porcelain surface wears. Learn how to refinish it yourself, or why professional refinishing is often worth it.
Why Cast Iron Tubs Are Special
Built to Last Forever
Cast iron tubs are virtually indestructible. Many are 50-100+ years old. The iron itself never wears out ā only the porcelain enamel surface.
Perfect for Refinishing
Solid, stable substrate. No flexing like fiberglass. Excellent adhesion. Professional refinishing on cast iron can last 15-20+ years.
Expensive to Replace
New cast iron tubs: $1000-3000+. Removal of 300-500 lb tub + installation: $1000-2000+. Total: $2000-5000+. Refinishing: $500-850.
Often Antique Value
Clawfoot and vintage cast iron tubs have character modern tubs can't match. Refinishing preserves the original tub while restoring the surface.
DIY Cast Iron Refinishing Steps
Check for Rust
Cast iron rusts where porcelain has chipped through. Sand rust spots with 80-grit, then treat with rust converter before refinishing.
Deep Clean with TSP
Porcelain holds soap scum in tiny pores. Use trisodium phosphate (TSP) and scrub thoroughly. Rinse completely.
Sand the Surface
Use 400-grit wet/dry sandpaper. Sand entire surface to degloss and create adhesion. Porcelain is harder than fiberglass ā expect more effort.
Fill Chips
Use marine epoxy or auto body filler for chips. Apply in thin layers, let cure, sand flush with surface.
Apply Coating
Apply 2-3 thin coats of tub refinishing epoxy. Cast iron's stable surface allows for better adhesion than flexible substrates.
Cure 48-72 Hours
Cast iron retains temperature ā wait at least 72 hours. Full cure takes 7 days for maximum durability.
Cast Iron Tub FAQs
How do I know if my tub is cast iron?
Knock on it ā cast iron sounds solid, not hollow. A magnet will stick to cast iron. Cast iron tubs are extremely heavy (300-500 lbs) and often have feet or a rolled rim.
Can rusted cast iron be refinished?
Yes. Rust must be removed down to bare metal, treated with rust converter, then primed before refinishing. Professional refinishers include this in their service. Severe rust may require additional repair work.
Is it worth refinishing a clawfoot tub?
Absolutely. Antique clawfoot tubs sell for $500-2000+. Refinishing at $500-850 preserves value while restoring the surface. New clawfoot reproductions cost $1500-4000+.
How long does refinished cast iron last?
Professional refinishing on cast iron can last 15-20+ years because the stable substrate provides excellent adhesion. DIY kits typically last 1-3 years due to thinner coatings and prep challenges. DIY vs professional