Here at Atelier Forma we believe that the more you get to know, the more you want to know! From delicate porcelain to the hardier stoneware, clay offers many builders and creators an exploration into its possibilities. Once you have explored one type of clay it’s exciting to start using another! Artists from around the world are continuously exploring the different ways in which we can form clay: whether it be for sculpting tiny figurines or building sturdy potting forms, clay is a world to discover and having the right clay is important. In celebration of clay let us delve into the array of different clays used at Atelier Forma’s studios but also around the world.
Porcelain clay is well-known for its delicate texture, ability to hold fine detail, and elegant appearance. It is a high-fire clay that is fired at temperatures of around 1220°C, making it extremely durable and non-porous. It is a favourite for some artists at Atelier Forma who sculpt animal and human figurines! After some experience at the wheel, builders can also use it to create lovely wheel-thrown vessels.
Earthenware is a low-fire clay that is fired at temperatures of around 1000°C. It is a very forgiving clay, making it ideal for beginners and those new to pottery. Earthenware can vary in colour from red to buff. It can however lead to cracking if not well-glazed. This type of clay is commonly used to make terracotta pots and other decorative items. Even though it is not used at our studios, it is worth mentioning it as it is one of the most common clays used, due to its abundance and accessibility. It can be found in abundance in Quebec especially south of St Laurence River.
Stoneware is a mid-fire clay that is fired at temperatures of around 1220°C. It is a durable and strong clay that is suitable for functional pottery like plates, bowls, and mugs. Our very own Chaga collection of mugs and bowls is created out of the alluring black stoneware clay. Stoneware is typically available in many colors: white, speckled, gray or red and has a smooth, non-porous texture that can be glazed to produce a range of colors and finishes. When working with the grey variety of stoneware clay, you will notice a wonderful grainy texture. Stoneware is also popular for hand-building techniques like slab building and coil building. When mixed with grog it gives a grainy finish, which can exfoliate your hands if you throw with it!
Raku is a low-fire clay that is fired at temperatures of around 900°C. It is a porous and grainy clay that is ideal for creating decorative pieces like vases, sculptures, and tiles. Often it contains grog which makes it resistant to thermal shock. Raku clay is often used in a specialized firing technique that involves removing the pottery from the kiln when it is still hot and placing it into a container of combustible materials like sawdust or leaves. This process creates unique patterns and colors on the surface of the pottery.
Terra sigillata clay
Terra sigillata is a type of clay that has been finely ground and mixed with water to create a smooth, silky texture. This type of clay is often used to create a polished surface on pottery, and can be applied either before or after firing. It is used as a surface decoration, not for building. After the application surface can be polished and it would leave a satin surface on the pots after firing (without any glaze applied on the piece). Terra sigillata can be made from a variety of clays, including earthenware, stoneware, and porcelain. We have it at our Fabre location. Ask your instructors!
Kaolin clay is one of the most popular types of clays used by potters due to its high plasticity and low shrinkage rate. It is a type of white clay that is named after the Kao-ling Mountain range in China where it was first discovered. Kaolin clay is typically found in deposits that are rich in feldspar, quartz, and mica. It's also commonly found in sedimentary rocks like shale and sandstone. Often it is used in glazes as a source of alumina.
Ball clay is a type of sedimentary clay that is highly plastic and has a high firing temperature. It's commonly used for making pottery due to its strength, plasticity, and workability. Ball clay is typically found in areas where the bedrock is composed of feldspar-rich igneous rocks that have been eroded over time. Also used in glazes, but all clays can be used to create a perfect custom clay body.
Bentonite clay is a type of clay that is known for its ability to absorb and retain water. It's often used in pottery as a suspending agent to keep glaze materials from settling to the bottom of a container. Bentonite clay is typically found in deposits that are rich in volcanic ash and is commonly found in areas like Wyoming, Montana, and South Dakota. It provides plasticity in the clay but also in glazes.
Red clay is a type of clay that is rich in iron oxide which gives it its distinctive red colour. It's commonly used in pottery due to its plasticity and workability. Red clay is typically found in areas where the bedrock is composed of sedimentary rocks like sandstone and shale that have been weathered and eroded over time. Red clay can be found in many different areas worldwide, from the rolling hills of England to the red deserts of the American Southwest. It's typically formed over millions of years as rocks are weathered and eroded, leaving behind fine particles of clay minerals that are then carried by water and deposited in low-lying areas. Some of the most common locations where clay can be found include riverbanks, floodplains, and areas where water collects, like swamps and marshes.
Exploring some of the clay types in our studio will help you discover which clay body you enjoy most. Our pottery classes and workshops offer beginner students 5 types of stoneware clays to build with. Students often start with speckled or granite and from there, they can explore other clays such as porcelain or the captivating black clay. Pick a colour, a texture or a story of the clay you’d like to work with and our teachers will help you advance your practice. If you haven’t yet, sign up for our newsletter to receive exclusive early bird registrations, special flash sales and more stories like this one!