Stoneware Crude glazes

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What are some crude glazes

Stoneware Crude glazes

We can create crude glazes from single materials. Borax can be dusted on a piece and fired to make a runny low-fire glaze. Galena (raw lead ore) was often used in the same way on folk pottery. Work fired in wood burning kilns is often glazed by the wood ash that flies along with the draft of the kiln. Depending on the build up of ash during the firing this creates from a light sheen to a thick runny glaze on the shoulder of the ware. Salt or sodium bicarbonate (baking soda) can be used to create vapor glazes. The salt or soda is thrown or sprayed into the kiln at peak temperature to create sodium vapor. The vapor condenses on the ware and combines with the clay to create a glaze. Sufficiently low temperature clay can be mixed into a slip and used a glaze on high fired pottery. Also, some feldspars melt at low enough temperatures to make crude cone 10 glazes. Some of these techniques are still used by potters who admire their simplicity and natural earthy aesthetic.
All of the above methods of glazing have inherent difficulties. Dusted on glazes can only be used on nearly horizontal surfaces. Wood firing is time consuming and labor intensive, and except in certain areas of the kiln, the deposit of fly ash is incidental--it makes beautiful accents, but it hardly qualifies as a functional glaze. Vapor glazing also glazes the entire interior of the kiln and all the props used to support the ware which considerably shortens their lives. Most of these glazes have serious flaws from a functional stand point. They make be crackled, excessively runny, or present problems in applying the glaze to the ware. The glazes that we'll be using are combinations of raw materials carefully combined to avoid these problems. They are applied as liquids to bisqueware and fired to cone 10 to melt them.

   

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