Making the right pottery in your studio requires the right choice of clay. The ideal clay body for your needs is dependent on various variables such as temperature range, the type of product you want to make, and the color. Each type of clay has different properties, benefits, and shortcomings. Therefore, it is important to understand the requirements of your pottery work and the available types of clay bodies.
The potter changes clay bodies for various reasons. They are first tested at multiple temperatures to provide the potter with the relevant information that can be observed, touched, or felt in the studio. The basic tests give you information that is specific to your needs.
How to select a pottery clay body
Most potters use commercially prepared clay, but it is crucial to ensure that you are getting the type you need for your work. You need to look into the end product, expertise needed and the costs incurred. Depending on what you are making, you may need more than one clay body, especially when using various construction methods. It will help to look into the following properties when choosing pottery clay;
Weight loss and shrinkage
Clay bodies shrink at different rates during drying and firing. The variations in shrinkage affect the final product; hence it is important to test a clay batch for the percentage of shrinkage before proceeding with pottery. Some products need a higher level of accuracy in the level of shrinkage than others.
Firing temperature
Each piece of clay needs to be fired to reach maturity. During the firing process, clay moves from a fragile material to a ceramic, making it impervious to water. The process consists of several stages in which the substance is passed through different temperatures. The temperature and time taken in each stage depend on the type of clay and the thickness of the piece.
Grog
Clay that was previously fired can be crushed to form a grog. It is added to the natural clay to give it a different texture and reduce weight loss and shrinkage. Grog comes in different particle sizes, and you can buy grog and clay separately or the mixture.
Types of Clay
There are different types of clay whose purposes and properties vary. These are;
Earthenware: It is the most common type of clay that is naturally found. They are highly plastic and contain mineral impurities such as iron that make them thick and hard. Earthenware is mostly used to make tiles, bricks, and other planting products.
Stoneware clay: It is the most versatile type of clay and easy to work with, especially for beginners in the pottery industry. Stoneware is available in various colors, and when fired, it is strong, durable, and non-porous. Due to its properties, it is used to make objects of different sizes that can hold liquid substances.
Porcelain clay: It is a very flexible and soft type of clay that is the most difficult to work with. It requires a lot of water to shape, and the potters need to regulate the amount to prevent loss of shape and collapse. It is used to make beautiful products and can be mixed with other types for easier workability.