[Linny]

How can I tell if my old tub is cast iron or steel?

I have a couple of spots where rust is showing through and I would like to repair it. Especially the spot near the drain.

 

[Grampa Bud]

If you can see the tub from underneath and it looks black it is probably cast iron. If it is more like bright metal it is steel. If you want, remove the overflow cover and popup lever from the head end of the tub and look at the edge of the hole. You should see black cast iron or bright steel. You could also rap your knuckles on one of your wife's metal mixing bowls and note the sound. (steel) Then if she has a black castiron skillet, do the same thing again. Note the sound.(cast iron) Now go rap on the long side wall of your tub. (Cast iron or Steel?)

 

[LookoutRanch]

Grandpa's right. You should be able to tap the tub with your fingernail, and if it has a light, tinny sound (tak, tak, tak), it's steel; if it sounds more solid, resonant or bell-like, it's probably cast iron.

Steel tubs are very thin with a light coat of enamel, like the lid of your old Kenmore top-loading washing machine.

 

[wrangler]

. If you want, remove the overflow cover and popup lever from the head end of the tub and look at the edge of the hole. ?)

If you remove the overflow cover, the material between it and the plumbing will be about 1/4 " thick if it is cast iron. 1/16" if it is steel. Or you can push against the skirt. If it flexes at all, it is steel... if it is solid, very likely cast. Cast iron does not rust as often as steel, but that is not to say that you will not get rust spots from a cast iron tub. Most steel tubs would have the same feel that kicking an older car might be imagined to be, where as cast iron would feel much more solid, like kicking a large rock.

 

[al's sewer]

The guys have it pretty well covered except If you can pick it up without giving yourself a hernia it is not cast iron.

 

[plumber Jim]

The guys have it pretty well covered except If you can pick it up without giving yourself a hernia it is not cast iron.

:laughing: If you can pick it up by yourself at all its not cast iron. :laughing: