“Temperature means nothing unless time goes with it.” Jim Bailey – designer/builder of Joan’s kiln, owner Bailey Ceramics.
Fire is a potters partner. Without transformation of clay by fire, it would melt back into mush whenever it got wet. Fire causes chemical changes that can vitrify particles into a non-absorbing glassy matrix – similar to what Earth does when magma flows during volcanic eruptions. During a firing everything in the kiln is yellow with heat, and the molten glaze becomes shiny and looks similar to wet ice. I see this while monitoring effects of time and temperature – measured by the pyrometric cones, as shown at left above.
Fuel might be electricity, gas, wood, oil, even dung and old tires. Each fuel influences the outcome, as do the chamber size, chimney, weather, fuel/air mixture, clay and glaze.
The day the first ocean sediment sample came. The kiln was hot and I jammed some into a spyhole – it melted into a green glob. Months later, I put it, thinned with water, on stoneware clay, and discovered granules. First I thought they were sand, but searched for an open door of someone with a microscope and he identified them as foraminifera.
So I left them in . . . . calcium carbonate . . . . hmmmmmm, I usually use that in the form of dolomite as a flux.
More on fluxed Earth . . . on a recent walking tour of Iceland , I picked up samples of crater ash, black sand, geyser mush, and volcanic humus from Ptingvellir, where Parliament always met, where tectonic plates move, and new land is created annually. Here, only sheep have claimed land between one side that is Europe , and the other side is North America .
Humus from this rift melts like other volcanic forms. Black sand from an Icelandic beach melts like black sand brought to me from Hawaii .
“We’re all floating on the same core”, said Matthew Person, a Woods Hole photographer who lived in Iceland for a year. And, because of doing this work, I've met New Zealand artist Brian Gartside who sees us standing on Earth, a spinning kiln.