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Porcelain Production

The fundamental material for the production of porcelain is kaolin. The largest deposits in the Czech Republic are located near Carlsbad and they are among those of the highest quality in Europe. It is a white matter which results from mineral weathering of feldspar. Its chemical composition may be expressed by the formula of Al2O3 - SiO2 - H2O. Besides the basic matter, kaolin also includes colloidal substances that cause its good ductility; however, their excessive amount results in excessive shrinkage of shaped items in the heat. The matter for the porcelain production also contains finely ground unweathered feldspar and silica. Shattered shards of defective products are also often mixed into the substance. The basic materials are ground in ball mills and mixed with water in a homogeneous slurry. The slurry is left to rest for a rather long time and then excessive water and air bubbles are removed from it.

Shaping and Firing

Shaping of required items from the basic material is performed on the modeling ring, by compression, or by molding (handmade production) of the matter diluted with water into plaster molds. The shaped products are dried in air, cleaned (retouched) and then fired in the furnace at 900 °C (the so called overheating). By firing, the atoms of aluminum, silicon and oxygen are rearranged and they form new bonds. This way, a hard material firm in pressure is formed, yet it is little impact resistant. By firing this material (unglazed) under high temperature is the strength and hardness increased, and the so called bisque. Bisque without any further treatment is mostly used for technical purposes. For the common use of porcelain, porcelain items are glazed – soaked up in glazing milk – a sparse slurry of the same composition as the porcelain matter.


Glazed products are then dried and fired at 1,400 °C. After this firing (the so called sharp firing), the volume of the product decreases by about 14%. There is a significant stress in the material, and some products are therefore also scraped from the top and fired on top of each other. Broad and open shapes in particular are very sensitive to curvature (e.g. some tea cups, etc.). At high temperature, the glaze is melted and fills the pores in the raw material. The fired item is left to cool slowly to avoid cracking in the glaze. The porcelain items are decorated by applying suspensions of metal oxides which provide the desired color shade after another firing. Due to the number firing (at least 4 firings with decorated porcelain), the production of porcelain is one of the most demanding sector regarding energy.

Stoneware, Earthenware and Pottery Material

Porcelain is similar to the matters of stoneware, earthenware and pottery. The stoneware is used as a construction material (tiles, stove tiles). The earthenware is used for cheap dishes and sanitation. Unlike porcelain, it is not transparent (items made of porcelain are transparent) and it does not produce a ringing sound when lightly struck. It is produced in a similar way as porcelain, fired at lower temperatures and the demands on the purity of the materials is much lower.

Note: Upon agreement, there is a possibility to use the services of our leading expert in the field of modeling services Mr. Kamil Ježek whom you could have seen in the show "Toulavá kamera". Besides our company, the art and expertise of Mr. Kamil Ježek is also used by our leading designer Mr. Maxim Velčovský, the studio Qubus, fa Whitefruits and others. You can watch our modeler in action here: http://www.ceskatelevize.cz/ivysilani/1126666764-toulava-kamera/207411000320211/obsah/121810-ruzovy-porcelan/

Kamil Ježek: e-mail: Jezecek1965@seznam.cz