Before pottery is made, the clay must be cleaned. Any dirt or small rocks must be removed. Then, if the clay has dried, the potter mixes it with water until it can be easily shaped.
The simplest way to make pottery is to start by making long ropes of clay. The potter then coils the strands on top of each other to make a bowl or vase shape. Finally the potter smooths the coils to make an even surface.
Another method of making pottery is called slip casting. The potter pours liquid clay into molds, where it hardens. Slip casting is useful for making pottery in flat or unusual shapes.
One of the most popular ways to make pottery is with a potter’s wheel. The potter first puts a chunk of clay on the wheel, which is a round, flat surface that spins around. The potter then shapes the spinning mass of clay into a pot. Because the wheel spins, it is easy for the potter to keep the sides of the pot even. The wheel is most useful for making rounded shapes.
Once the pottery is shaped, it is prepared for firing. The pottery must be completely dried. It will dry slowly in the air, but today many potters use automatic dryers to speed up the process. Sometimes the potter carves the pottery before it is fired. Using a blade, the potter can thin a pot’s walls or create decorations.
When the pottery is ready to be fired, the potter places it in a kiln, or high-temperature oven. The temperature needed depends on the type of pottery and its decoration. Earthenware may need a temperature of 760° C (1,400° F). Stoneware or porcelain may need a much higher temperature of 1,480° C (2,700° F).
After firing, the hardened pottery can be glazed and painted. Glazes are made of ground minerals that produce different colours. Iron oxide (green), ferric oxide (yellow), copper (red) and cobalt (blue) are some common glaze ingredients. Other materials used in glazes include feldspar, quartz, silica and boric acid. Depending on the type of pottery, paint may be applied either under or over the glaze. After glazing and painting, the pottery is often fired again so that the glaze hardens and becomes shiny.
