Porcelain manufacturing

Since 1996, in addition to painting, we have expanded to the manufacturing of porcelain and now the majority of our products are produced here.
 
Porcelain, like all classic ceramic products is made up of three materials: kaolin (China clay), quartz and feldspar. When mixed with water, kaolin becomes malleable, easy to shape; objects worked of kaolin preserve their shapes even after drying and firing. Feldspar helps the material pack during firing, as it starts softening as low as 1100°C due to its high alkali-oxide contents. The role of quartz is twofold: on the one hand it contributes to translucency, on the other; it significantly influences the stability of ceramics during firing.

Porcelain is produced through casting. The preparation of liquid paste starts with dispensing all the basic materials and homogenisation. Then the paste is put into a mixing container where it is constantly stirred with a low speed revolving spiral agitator for about 4-6 days, in order to evacuate the air pockets.

For casting we use plaster mould. Plaster is the most important auxiliary material of ceramics production. If mixed with water plaster powder has the particularity of making a paste that may be easily molded, and hardens in relatively short time. Still, after hardening, it is quite easy to carve it, and after becoming completely hard, it is also solid enough to withstand the physical stress during shaping and transportation.

In addition, due to its porosity the plaster sucks out the water from the clay. The plaster mould allows the same size and pattern for the serial production of ceramic ware.

There are two ways of shaping the objects by casting: the clay can be casted in open and closed moulds.
The open or hollow casting procedure requires the mixing of the clay in the mould; otherwise, the thickened clay would make the inner surface of the object rough. The unwanted sludge is drained down, and after a while the drying and shrinking object may be taken out easily from the mould. Depending on their size, the moulds may be used 2-4 times a day, than they have to be dried out.

The closed casting procedure is generally used for shaping trays, platters and other similar objects. The outer and inner surfaces of the objects are both shaped by the plaster mould, as the clay is molded between two plaster walls. Because of the water being sucked out, the casting sludge should be refilled in order to keep constant the level of the casting clay, until the hardened material fills up completely the mould.

A plaster mould can be used ca. 100 times.