AMDZen
Lifer
It's not real hard to tell. Cast iron tubs have an unmistakeable sound and solid feel to them when you wrap your knuckes against the sidewalls.
Fiberglass or acrylic tubs take 5-10 years to start developing cracks in the bottom.
So it has to be cast iron or acrylic, those are the only options? Bear in mind that my house was built in 1960 and I've owned it now for 8 years. I don't think the previous owners swapped the tub within 2 years of when I bought the place. In fact I guarantee it.
