How to Identify a Cast Iron Tub

Cast iron tubs were popular during the late19th century, but they have recently come back into style for modern bathrooms. They are constructed from melted iron, which is poured into a mold in the shape of the tub. When the iron cools, the iron finish is one of the most durable tub materials available. One of the main benefits of cast irons tubs is that they retain the heat of water much longer than other tub materials, thus making baths more enjoyable.
Step 1Tap on the side of the tub with the metal end of a screwdriver. If you hear a ringing sound similar to a bell, then the tub is made of cast iron. If the sound is more tinny, then it is probably made of steel.

Step 2Look at the bottom of the tub to see if it has claw feet. Most claw-feet tubs are constructed of cast iron, whether the tub is an antique or a more modern version.

Step 3Lift up on one end of the tub to see how heavy it is. If you have extreme difficulty lifting the bottom even an inch off of the floor, then is it most likely cast iron. The average cast iron tub weighs between 300 and 500 pounds, requiring three to four people to lift.

Step 4Examine the porcelain coating on the exterior of the tub to ensure that is has very few chips or scratches. Porcelain adheres more strongly to cast iron than other tubs, so it rarely chips. If the porcelain contains many chips, then the tub is most like made of steel.

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