Crystalline glazes are probably the most difficult and frustrating glazes to develop, but Phil, who is a ceramic engineer and passionate about these glazes, gets impeccable results with almost every firing. My son is quite fortunate to have him as a glaze mentor and Phil, while adept at glazing, is not a potter, and is fortunate to have had some of my son’s pottery pieces to showcase his expertise.
Each individual crystal grows during the firing process, within the glaze, on the surface of the pot, similarly to the way ice crystals grow on a window pane forming frost. To get the glaze to work, all the variables must come together precisely.
First the piece of pottery is turned on the potter’s wheel and bisque fired in the kiln. Then the surface area of the pot is measured and is carefully coated with just enough glaze, at just the right thickness, to cover that pot. The piece is then placed back in the kiln to be fired again. After the kiln reaches exactly the correct maximum temperature it is cooled for an exact time and then kept at a constant temperature for an exact number of hours. It’s during this “soaking” period that the zinc silicate crystal growth occurs.
Even though the glazing and firing must be precise, the exact crystal growth and patterns are beyond control. Each piece is truly unique and one of a kind!
In the view of the piece below you can see the whole form made by Andrew on the potter’s wheel, a perfect canvas for Phil’s exquisite glaze, and available for purchase at our little family gallery, Bostree, in Sugar Loaf, NY.
Thank you Jennifer for the One Word Photo Challenge: Taupe!