Thanks all! The aluminum is blackened with some kind of enamel. It's not anodized. I get the stuff from Main Trophy Supply http://www.maintrophysupply.com/aluminum.htm. It is the item 108 on this page. VERY easy to use for this process. No japanning of tin, no cleaning glass. Just peel of the plastic cover sheet and pour. And they will cut it to size for you for a nominal fee.
kerik, astouding as usual. I find it amazing when a photographer can take a similar concept and execute it in so many unique ways, while still having threads of similiarity. Its humbly to have even small jpg thumbnails next to such exquisite work.
thanks for continuing to sharing these with us.