There are two different reasons that clay presses are used. First, a clay press can be used to remove excess water from clay, particularly when making clay used for modeling or pottery. The second reason for using a clay press is to shape the clay into any number of forms, such as sheets and different shapes. These types of clay presses are also referred to as press molds and often also dry the clay out at the same time as shaping it.
There are many types of clay, both naturally and industrially made. Clay is very versatile and can be used to make any number or items, from sculptures to dishes, bricks and jewelry. Along riverbanks and in damp areas, natural clay is often found where dirt and sediment has collected over time. The amount of water found within the clay is important in determining how useful it will be. Too much water and the clay turns to a slurry and won’t hold a shape, while too little water means the clay will be too dry so that it crumbles instead of sticking together.
It is common for clay that is harvested naturally to need to have some of the water removed, particularly if it has been taken from a river or stream bed. By using a clay press, water can be squeezed from the clay so that it becomes more solid and can then be shaped. The more water that is removed, the more solid the clay will become. Bricks can be formed by using a clay press to remove as much water as possible, while shaping the clay into the correct shape. The bricks are then fired to make them waterproof and to keep their shape.
Press molds are used to create designs and shapes from clay when making pottery, jewelry and other arts and crafts items. Usually, these types of clay presses are made of a material that will absorb the water out of the clay as it forms the desired shape. Plaster is commonly used to make clay presses as it contains less water than clay. This means that the longer the clay is left in the clay press, the drier it will become. The drying not only helps the clay hold its shape, it makes it easier to remove from the clay press as it will pull away from the sides of the mold as it dries.