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Forming method of pottery
Different characteristics of green body

To make pottery, the body must be transformed into the required shape, and then heated to a high temperature in a kiln to promote permanent changes, including increasing strength, hardening and fixing the shape. According to different regions, the clay used by ceramists has different properties, which often helps to make pottery with local characteristics. It is also a common practice to mix other minerals in clay to achieve specific purposes. For example, after firing, the blank with slightly higher porosity is often used to make pottery pots or Songkhla pottery flowerpots.

Mud rubbing and air drying stage of green body

Before most molding processes, it is necessary to first remove the air from the blank. The above method is called degassing. You can use a vacuum pump or rub mud by hand. Rubbing mud can help to evenly distribute the water in the blank. After degassing and mud wiping, the green body is shaped by various processes. Dry after mol, and then firing. The drying process is divided into several stages. "Leather hardness" refers to the stage when the blank is about 75-85% dry. Trimming and adding handles usually occur in the semi-dry and wet stages. "trunk" refers to the stage when the green body reaches a water content close to or equal to zero. Unfired objects will be called "green pottery".

The most basic tool for potters is their hands. However, due to the long-term evolution of pottery manufacturing history, other additional tools have been developed, including pottery wheels and turntables, molding tools (clappers, mats and plasters), roller tools (roulette, clay tablets and rollers), cutting/hollowing tools (knives, slotting tools and wiring) and finishing tools (polished stones, wooden files and suede). Put the clay ball in the center of the turntable, which is called the wheel head. The Potter pushes (foot-operated billet puller or pedal wheel) or variable speed motor with a stick or foot. Usually, a plate made of rubber, wood or plaster of Paris is put on the grinding wheel head, which is called the blank bottom plate, and then the mud balls are thrown on the blank bottom plate instead of on the grinding wheel head, so that the finished product can be taken out together with the blank bottom plate without deforming it.

In the process of blank drawing, the pottery wheel will rotate at high speed, and the clay ball will be pressed, squeezed and slowly pulled out to become hollow. The first step is to press the rough clay ball downward and inward until it is perfectly rotationally symmetrical, which is the most important and difficult technique to master. Then "open" in turn, that is, punch a central hole in the mud ball; "Laying the bottom plate" means making a flat or round bottom in the container; "Throw" or "drag", that is, draw the shell closer and shape it into the same width; "Trim" or "flip", that is, remove excess clay to trim the shape or make a foot.

Although pottery wheels are usually used to make individual pottery, they can also be used for mass production. Making pottery wheels requires a certain skill of a ceramist, but a skilled mechanic can make almost the same plates, vases or bowls in one day's work. Due to the inherent limitations of the pottery wheel itself, it can only be used to make pottery that is radially symmetrical on the longitudinal axis. This situation can be made more interesting visually by stamping, unfolding, carving, making grooves, cutting surfaces, V-shaped cutting and other methods. Usually, the pottery made of drawing blanks will be further transformed by manual skills, adding functions such as handle, cover, foot and spout. Casting slurry molding method is often used for batch production of ceramics, and it is also most suitable for pottery that cannot be molded by other methods. Mix water with green body to make mud glaze, and then pour it into gypsum mold with high water absorption. The moisture in the mud glaze is sucked into the mold, leaving a layer of blank to wrap the inner surface, forming an inner shape. Pour the excess mud glaze out of the mold, then open the mold and take out the contents. Grouting molding is very common in the manufacture of bathroom products, and it is also used to make small handicrafts, such as complex and exquisite statues.