Glazes: an introduction
Glazes can be classified into two simple groups, which are earthenware and stoneware. These groups can also be classified by firing ranges for individual glazes. Earthenware glazes mature in the range 950°C to 1190°C, where as stoneware glazes fire in the range 1200-1300°C. Some crossover can occur between the high earthenware and low stoneware temperatures. For ease of selection sub-groups are arranged within these groups based on temperatures ranges. Other methods of grouping are based on colour or finish (e.g gloss, opaque, matt etc) or even speciality (e.g. raku). At Clayman we also include a third large group called Brush-on. These are glazes that were initially developed for the hobby market. but are now used by many studio potters and education, for the many additional qualities they offer. All glazes under brush-on start out life as a earthenware or stoneware glaze, but are then added to a media or gel that places them into permanent suspension to make application by brush easy. All brush-on glaze manufactured by Clayman are available in powder form as well.