1. The magnet test
Hold a fridge magnet against the side of the tub. Sticks firmly: steel or cast iron. Slides off: acrylic or fiberglass.
Guide
What kind of bathtub do I have? Steel, cast iron or acrylic.
A fridge magnet and your knuckles are all you need. If the magnet sticks, we can almost certainly refinish it.
Three quick tests
Find out in under a minute.
We refinish porcelain-enameled steel and cast iron tubs. Here's how to tell whether yours is one of them.
2. The knock test
Rap it with your knuckles. Cast iron: a deep, dead thud. Steel: a brighter ring. Acrylic or fiberglass: a hollow, plastic knock.
3. The touch test
Enameled metal feels cold and hard as glass. Acrylic and fiberglass feel slightly warm and give a little when pressed.
Compare
Cast iron, steel or acrylic?
| Cast iron | Steel | Acrylic / fiberglass | |
|---|---|---|---|
| Magnet | Sticks | Sticks | Doesn't stick |
| Sound | Deep thud | Lighter ring | Hollow knock |
| Feel | Cold, rock solid | Cold, firm | Warmer, slight flex |
| Weight | 300 lb and up | Around 70–120 lb | Light |
| Typical damage | Chips showing black iron, worn enamel | Chips with rust halos, rusty drain ring | Cracks, yellowing, dull patches |
| Usually found in | Older homes, clawfoot tubs | 1950s–80s homes and condos | Newer homes, one-piece tub-shower units |
| Do we refinish it? | Yes | Yes | No |
Why we only refinish steel and cast iron
Porcelain enamel is glass fused to metal: rigid, stable and, once properly etched, an excellent base for a new coating. A bond to enamel doesn't move, so the new surface doesn't crack.
Acrylic and fiberglass are plastics. They flex slightly every time someone steps in, and they expand and contract with hot water. Coatings on a surface that moves are far more likely to crack and peel. Rather than sell a finish we wouldn't warranty, we simply don't take those jobs.
Clues from the age of your home
- Before about 1960: very likely cast iron — built-in or clawfoot.
- 1960s to 1980s: most often porcelain-on-steel, especially in Honolulu condos and walk-ups.
- 1990s and newer: frequently acrylic or fiberglass, particularly one-piece tub-and-wall units in newer subdivisions.
These are rules of thumb, not guarantees — bathrooms get remodeled. The magnet doesn't lie.
Still not sure?
Text a photo to (808) 208-1000. We can usually tell at a glance, and we'll confirm the price at the same time.
Other things we look for
- Shape. Standard rectangular and clawfoot tubs are fine. Unusual corner or multi-sided built-ins aren't.
- Handles. Tubs with grab handles molded or mounted into the walls of the tub aren't a fit for a poured coating.
- Shower doors. A sliding door frame on the tub rim needs to come off before we arrive so the whole tub can be coated.
- Previous coatings. Fine — tell us, and send a photo of any peeling.
Free estimate
Ready to bring your tub back to life?
Send a couple of details or text us a photo — we'll confirm the price and offer the next available date on Oʻahu.
- Text a photo of your tub to (808) 208-1000, or use the form.
- We confirm your price — a flat $635 for a standard tub — and a date.
- One visit of about 3 hours. Your tub is ready to use 24 hours later.