Phil, I hope you're not expecting the clay to be heated! ;)
It's too far from my solar water heater to circulate hot water through it. So, if you do decide to test it, I'd suggest you throw one of the models in first, and climb in on top of her so she can shield you from the cold.
I finished excavating today and put the liner back, for the last time. Now, all I can do is wait for my clay delivery. If that doesn't work out, I'll be off to Augusta, GA to fetch some kaolin clay. I'm not sure I'm crazy about the look of white clay. From a photographic point of view, it would be a nice change from black mud, but it would not match the surrounding landscape. Maybe if the local clay doesn't work out, and I get the kaolin clay, I can mix in some local clay to give it a more natural color and to make up for any shortage in volume. I'm estimating that 2000 pounds of powder will do it, but I'm not confident.
The mud-bondage guy