What is my bathtub made of? Steel, cast iron, acrylic or fiberglass
It matters, because we refinish only two of the four. You can find out in a minute with a fridge magnet and your knuckles.
Three checks, no tools
1. The magnet
Hold a fridge magnet to the inside wall of the tub. If it sticks, the tub is steel or cast iron. If it falls off, the tub is acrylic or fiberglass.
2. The knock
Rap the side with your knuckles. A deep, dead thud is cast iron. A higher metallic ring is steel. A hollow plastic sound is acrylic or fiberglass.
3. The flex
Press hard on the side wall or step in. Metal tubs do not give. Plastic tubs flex, and the floor may move slightly.
How to tell them apart, and what we do with each
| Cast iron | Steel | Acrylic | Fiberglass | |
|---|---|---|---|---|
| Magnet | Sticks | Sticks | Does not stick | Does not stick |
| Sound when knocked | Dull thud | Metallic ring | Hollow, plastic | Hollow, thin |
| Feel | Cold, rock solid | Cold, solid | Warm, slight flex | Warm, flexes |
| Typical damage | Worn floor, chips, rust halos | Chips, rust at the drain | Scratches, cracks | Dull, chalky, cracks |
| Usual era in the Valley | Before about 1960, and clawfoot tubs | 1950s–1980s | 1990s to today | 1970s to today, often one piece with the shower walls |
| Do we refinish it? | Yes | Yes | No | No |
Why we do not refinish acrylic or fiberglass
Acrylic and fiberglass tubs flex. Every time someone steps in, the surface moves a little, and a rigid coating on a moving surface is under constant stress. These tubs also need different preparation and different products.
Our method was developed for rigid, porcelain-enameled metal, and we would rather tell you that than take the job and hope.
For a plastic tub that is only dull, a marine-style polish can bring back the shine. For one that is cracked or soft underfoot, replacement is usually the lasting fix.
A few metal tubs we turn down
- Tubs with grab handles built into the walls
- Tubs that have had an acrylic liner installed over them, even if it was later removed
- Tubs with a crack or a hole through the floor
- Corner tubs and other non-standard shapes
About tub materials
How do I know if my tub is porcelain?
“Porcelain” tubs are steel or cast iron with a porcelain enamel surface. If a magnet sticks and the surface is hard and glassy, that is what you have.
My tub and shower walls are one piece. What is it?
A fiberglass or acrylic tub-shower unit. They were installed widely in Valley homes and apartments from the 1980s on. We do not refinish them.
The magnet sticks, but only weakly.
Cast iron under thick porcelain can feel weaker to a small magnet. If it holds at all, the tub is metal.
Can I send a photo instead?
Yes. We can usually tell the material from a photo of the whole tub and one of the drain. Text it to (602) 733-0000.
Send a photo. Get a real price today.
No home visit needed for a quote. A photo of the tub is enough for us to confirm the price and offer a date.
- Text a photo of your tub to (602) 733-0000, or use the form.
- We confirm the price — $475 for a standard tub — and a day.
- One visit of about 3 hours. The tub is ready to use 24 hours later.