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In clay bodies a flux creates a limited and controlled amount of glass, which works to cement crystalline phases together. Fluxes play a key role in the vitrification of clay bodies by lowering the overall melting point. The most common fluxes used in clay bodies are potassium oxide and sodium oxide which are found in feldspars.
The vibrancy that only underglaze was able to supply is now achievable with a variety of over-glazes therefore discounting the advantage that underglaze commercial production had. A well-known New York underglaze tile and pottery decorator of the 1940s, Carol Janeway (1913-1989), was diagnosed with lead poisoning after eight years of using a ...
Glazes need to include a ceramic flux which functions by promoting partial liquefaction in the clay bodies and the other glaze materials. Fluxes lower the high melting point of the glass forms silica, and sometimes boron trioxide. Raw materials for ceramic glazes generally include silica, which will be the main glass former.
Hard-paste porcelain was invented in China, and it was also used in Japanese porcelain.Most of the finest quality porcelain wares are made of this material. The earliest European porcelains were produced at the Meissen factory in the early 18th century; they were formed from a paste composed of kaolin and alabaster and fired at temperatures up to 1,400 °C (2,552 °F) in a wood-fired kiln ...
Though the recipe of tin glazes may differ in different sites and periods, the process of the production of tin glazes is similar. Generally speaking, the first step of the production of tin glazes is to mix tin and lead in order to form oxides, which was then added to a glaze matrix (alkali-silicate glaze, for example) and heated. [19]
İznik was an established centre for the production of simple earthenware pottery with an underglaze decoration when, in the last quarter of the 15th century, craftsmen in the town began to manufacture high quality pottery with a fritware body painted with cobalt blue under a colourless transparent lead glaze.
A procedure for preparing clay or a clay body by hand: the lump of clay is repeatedly thrown down on a work bench; between each operation the lump is turned and sometimes cut through and rejoined in a different orientation. The object is to disperse the water more uniformly, to remove lamination and to remove air. Whiteware
Glazes can change the chroma, value, hue and texture of a surface. Glazes consist of a great amount of binding medium in relation to a very small amount of pigment. [1] Drying time will depend on the amount and type of paint medium used in the glaze. The medium, base, or vehicle is the mixture to which the dry pigment is added.