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Product Usage of the Glazes

 

Ceramic Glazes

Ceramic Glazes are milled glasses of special composition with an addition of kaolin, stains, colouring oxides, opacifying agents and other additives. They improve the surface of ceramic products, increase their chemical and mechanical resistance and their appearance and secure no soaking through. The thermal expansion of the fired glaze should correspond to the expansion of the ceramic body in order to avoid crazing, shivering or peeling off the piece. The right glaze is to be chosen regarding to supposed firing temperature, that depends on used body clay.

 

Packing and Storage

Our glazes are delivered in a dry state in tin barrels with a PVC-enclosure, paper or PE-bags, depending on a delivered quantity. Storage of dry glazes is not limited, if moisture and/or dust are avoided. The water suspension should be stored shortly because no conservants are added.

 

Usage

Dry glaze is to be dissolved in water to thick paste which should be thinned to proper density. Mellowing and screening before use is pertinent. The glaze density depends on the way of application and on the body porosity. A thick porous bisque, which absorbes the water fast, requires rather a thinner glaze than a tighter, less porous body, which absorbes the water slowly. Each glaze is recommended to be tested with various layers on the body concerned and under determined conditions. The layer should be up to 1 mm; generally transparent glazes are glazed thinner than the opaque ones. In order to avoid the settling out we recommend you to use an electrolyte Ls 040 18 amounting to 1-2 ml for 1 kg dry substance. The mixing of the glazes is possible in order to change colour shade, melting properties or to achieve some artistic effects. Sometimes the glaze coat can crawl due to the presence of dust, grease or dirt on the bisque. Common bisque firing (earthenware) should be 50°C (2 cones) hotter than the glaze fired. Stoneware bisque firing is up to 800-900°C. In some cases it is possible to glaze the green body and to fire once only. Glazed pieces have to be well dried before the firing. The firing temperature should correspond to given data. When fired less, the glaze will be rough and matte, fired hotter, the glaze runs down the piece or soaks into the body.

 

Checking and testing

Each batch is tested in the Departement of Quality Check-out according to obligatory testing methods and the Quality Assurance Manual in accordance with ИSN EN ISO 9001. Paramatres under testing are: grain size, humidity, colour shade deviation and surface appearance against the standard fired sample.