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BearTrack Farm Pottery               Glazes   All glazes used at BearTrack Farm Pottery are mixed from nontoxic raw materials using recipes based upon traditional formulas.   Presently, we are researching and developing a palette of glazes based upon iron oxide as the principle coloring agent.   Making up 7 percent of the top layer of the earth's crust, iron oxide is the most common coloring oxide in ceramincs.   Iron glazes are the largest and most interesting class of glazes because iron can create so many different colors and effects.   One can acheive differing groups of glazes as celadons, temmokus, and iron-saturated by altering the amount of iron in the recipe.   Iron glazes were by far the most common ones developed in China from 1000 BC to 1000 AD.   The entire history of Chinese ceramics can be regarded as an intense study of the effects of iron in glazes.   In their mastery of these glazes, they were able to produce blue, green, olive, brown, black, yellow, russet, oil spot and even iridescent silver glazes.   Drawing on the German tradition of salt firing, Michael Kielman adds a measured amount of salt into the back of the wood-fired kiln's firebox at the end of the firing.   At the high temperatures in the kiln, the salt (sodium chloride) vaporizes into an excited state that can separate into sodium and chlorine gases.   The sodium joins with the silica and aluminum in the clay body to form a simple glaze.   The free chlorine combines with various oxides such as iron, hydrogen, potassium, silica, chromium, and copper.   These can create very active and interesting effects.   Our research into these glazes is ongoing.   Our color palette includes blue, green, amber, black and orange as pictured in the photos below.  Click on these pictures or links for more information and pottery featuring these glaze types.  Our color palette will continue to develop as our knowledge about these glazes, their firing requirements and interaction increases.   Your input on these glazes is appreciated.       Celadon   Temmoku       Shino