Egyptian Paste/Faience - Drying |
Egyptian Paste after the firing (right one has gold luster too) |
It is a self-glazing material. Despite what a lot of archaeologists and Egyptologists say, it is not glazed ceramic, a more apt description would be to simply call it glaze, all by itself. Essentially it is an alkali based glaze. As it dries the salt (alkali) migrates to the surface of the piece. When it fires the colorant (most often either copper carbonate or cobalt oxide) are drawn to the surface as well and flux with the alkali to create the hard outer shell.
Although we do not have the ancient recipes, there are a number of recipes available online that can duplicate it pretty well. I got mine from Robin Hopper's book The Ceramic Spectrum.
I had seen many amulets and bowls in Egyptian Faience in my research so I made a bunch of shapes: hippos, scarabs and small press-molded bowls. I then painted manganese dioxide on the outside of the dried pieces not exactly knowing how it would react, but it fluxed right along with the alkali and the copper. The Egyptian paste is fired to between cone 012-08 (different recipes call for different temperatures)
On some of the pieces I added gold luster and fired again to cone 018, also as an experiment. It worked beautifully!