Bone China is a porcelain clay mixed with bone powder and quartz. It is light in texture and milky white in color. When placed under the light, it can faintly transmit light. Bone china was invented by the British in 1794. In the process of making bone china, animal bone meal is added, and bone meal is made of cattle, sheep and pig bones, among which bovine bone is the best. Generally speaking, if the raw material contains 25% bone powder, it can be called bone china, but the best bone china recognized in the world must contain 51% high-quality bovine bone powder. Bone meal can also increase the hardness and light transmittance of porcelain, which is twice as strong as ordinary ceramics, and can also be made thinner than half of porcelain. The greater the bone meal content, the easier it is to burn and crack during the firing process, the scrap rate will increase, and the finished product will be more expensive.
Bone china products contain more than 40% of the utensils, which can be called high-grade bone china (fine bone china). Someone once did an experiment, placing four bone china cups on the wheels of a Rolls-Royce car Under the circumstances, the four cups can bear the weight perfectly.
Thin bodied porcelain is also known as “bodiless porcelain” and “eggshell porcelain”. It is one of the traditional porcelain. The characteristic is that the thickness of the carcass is mostly within 1 mm.
The production of thin-bodied porcelain is very difficult and highly technical. Thin-bodied porcelain is very thin and has low strength, so it is very easy to break and deform during the production process. When making it, you must have superb and skilled skills, as well as strict implementation standards and process regulations. In the batching, in order to prevent the deformation of the thin tire products during the firing process and improve the whiteness and transparency of the glazed products, it is necessary to increase the content of aluminum oxide (Al2O3) in the blank and magnesium oxide (MgO) in the glaze . When trimming the blank, it is necessary to go through the operation of rough repair and finishing, and trim the thicker rough blank into a fine blank with a thickness of each part less than 1 mm. Before glazing, the blank should be fired at a temperature of 750-800 degrees Celsius. When glazing, the inner glaze uses the glaze method, and the outer glaze uses the spray glaze method. The thickness of the glaze layer is about 0.1 mm. The casket adopts a special pad cake, so that the fine blank can be smoothly loaded into the sagger. The firing temperature is 1280-1320°C.
The production process of thin-bodied porcelain requires more than 40 processes from batching, billet drawing, billet trimming, glazing to painting and firing, all of which must be done manually and divided into three firings. Among them, the billet and artistic processing should be the most delicate. Among them, the rough billet has to go through rough trimming, fine trimming, and intensive repairing hundreds of times before the rough billet with a thickness of two or three millimeters can be trimmed to about 0.5 mm. The varieties of thin bodied porcelain include bowls, cups, plates, saucers, cups, leather lamps, vases, stationery, wine utensils and so on.
Post time: Aug-16-2023