I would give the Shidoni Foundry, just north of Santa Fe, NM a call. I was there once on a Saturday and got to seem them pour several hundred pounds of bronze, way cool!
They use a lost wax process and coat the wax with investment material. As much as I can remember they dipped the wax in a liquid then dip the coated wax in a fluidized bed of investment silica material. When that was dry they would go back do it again and again to build up the thickness to the desired level. Then it went to a huge burnout oven to melt out the wax and harden the mold.
At the time they had open house on Saturday with a pour in the afternoon. You could walk around the shop, talk to the tecks and artists. Then stand 10' from several hundred pounds of bronze being poured into various projects. We were so close, if lade had broken our feet would have been in serious hurt.
If you find out the nature of the materials please post.