Whats in a solar holding tank?

I have someone offering me a couple of solar holding tanks in her basement. Is there a decent amount of copper inside or is it just a holding tank like a water heater? Someone also told her their was rock inside them. I find that kind of hard to believe

I've worked with them before.

They aren't terribly different from a water heater. Same basic idea, except that they generally have a copper coil heat exchanger inside. It's been 20 years or more since i've scrapped out a heat exchanger but i think you might get around 10 lbs of #2 copper out of it.

They vary in quality too. The one Mike linked to is porcelain lined inside to resist corrosion. The really nice ones are stone lined and very durable ! The stone lined hot water storage tank that i have for my wood stove was originally put into service in 1962. I expect that it will easily outlive me.

The stone lined ones are really heavy.

If you can find the make & model # on the tank somewhere ... you might be able to look up the specs on-line. That way you would know about the quality of the build and what kind of weight you're dealing with.

thanks guys kinda what I figgered. I passed on it