Firing Egyptian paste cone 04, 1940°F/1060°C

Opening a kiln is a kin to payday. Open that envelope, there in find exactly what you've work for. Every now and then it's short or there's a bonus, either way you find yourself investigating why. It's kind of nice when firings go as planned.

Looking so generic going in, then turning brilliant coming out, it always surprises. It's the same as glaze firing, but you skipped one step (actually 2 steps, the bisque and the glaze application).

Firing hotter just to see what would change is a bit of a let down. The differences in color were only slight, possibly nonexistent.

The Thicker, The Glossier

Stands to reason that larger/thicker pieces have a Glossier finish, than smaller ones. Does it not? A thicker piece takes longer to dry, yes? With longer drying time more salts wicks through to the surface, agree? The more salts on the surface the thicker the glaze forms, right?

The two figures in the image here are constructed from the exact same clay/Egyptian paste mix. They dried next to each other; they were fired along side one another in the kiln. Mason stain, pansy purple, was added to the basic mix, 2.5% by weight. You can observe here that the thicker the glaze the bluer it appears. On the bottoms where no evaporation occurs their color appears identical.

Lots of cracks developed in bigger pieces as they dried. Possibly, the introduction of sand or grog would alleviate this cracking. Of course additions to the basic recipe might also affect the color. The addition of grog would also improve this clay's ability to stand up. There’s always more experimentation to be done.

Firing Egyptian Paste, Houston We have FAIENCE!!

Opening a fired Egyptian paste kiln is one of the more exciting occasions in the studio. You always know you will get some little gifts. If you're like I am you will have an experiment or two running. So there's going to be some disappointments too. I really shouldn't call them disappointments; we need to think of them as learning experiences. There's serendipity too!

This last Egyptian paste kiln firing was no exception to the excitement rule. The paste goes in the kiln so nondescript and comes out so vivid. There were some surprises. Just 2.5 percent pansy purple mason stain yielded a much deeper color than expected; I can cut that down to 1% in future firings. The base recipe for Egyptian paste without colorant came out a pale gray, nearly white. I imagine with the addition of tin oxide or zinc oxide a true white may be obtained. That is the basis for another future experiment. I had a few experiments going on in this kiln that will be covered later on. For now, I can say that over all I was pleased with this firing.

My bead island performed marvelously as expected. The beads came off quite easily. Of course there was a layer of shelf primer on the peaks to keep the bead holes from sticking. Painting them with a layer of wax resist will keep the salts/fluxes from being absorbed by the clay of the island. In this firing, I neglected to do this wax coating and yet there was little sticking.

This firing was cone 06, that's about 1800 Fahrenheit/1000°C. A cone firing is a measure of work done by heat rather than temperture; the cone is formulated to melt at a certain temperature so when it bends the kiln is said to have reach temperature. Were I firing by pryrometer I would probably have to hold the kiln at temperature. Most potters just fire up to cone 06 then shut the kiln off. In my case, the “kiln sitter” shuts the kiln off. My next firing I'm going to try taking the kiln up one cone hotter to see if I can get the paste to flux a little bit more. More variation in the color would be nice. The the beads look a little too controlled, not enough like the ancient Faience. Even so, some of the ancient Faience is this turquoise.