I have a cast steel black enameled double bowl sink. My wife call out of state to say the BOTTOM of the sink is cracking and will break through. I am looking for a detail or description of how the underside of sinks are insulated for water temps and sound??

Frank

For a steel sink they are coated with a coating of something that looks like roofing cement. The cast iron sinks do not have any insulation on them. This mostly for the dulling of the sound that working in the sink causes.

If the enamel is cracking I don't think that has anything to do with the actual sink itself but the coating on the sink.