Randy and Larry,
Thank you for responding. What a comfort it is to have you as advisers.
As Larry recommended, I am going to put the tempering tank in the attic with a drain pan that will also collect dripping condensation.
I jumped the gun and removed the shell before reading your replies. The main benefit for me is that the tank is now shorter, lighter and easier to install in the attic. I’m unsure whether the missing insulation will make any net difference.
I tried the tank out in the backyard yesterday and enjoyed a slightly warm shower after it had spent a day in the sun.
The top and bottom of the tank are both concave and made of iron. The cylindrical wall is copper-nickle, and I imagine the inner surfaces of the ends are coated with copper-nickle. When I emptied the tank, there were no signs of rust and essentially no sediment. But there was a thin inky black deposit coating the bottom, something that must have accumulated over the past half century.
Any idea what the deposit is or how best to get rid of it? I’m thinking of emptying the tank then pouring in a gallon of vinegar with plenty of salt. That combination works well on old pennies and also on the exterior of the tank.
Should I think about installing a long curved inlet tube so I don’t have to deal with this problem again 50 years from now? But maybe that’s not an option since the inlet port is on the side of the tank, as are all the ports.