Functional pottery—bowls, mugs, plates—connects us to the earth in a tangible way. Choosing the right clay is the first step in creating pieces that are not only beautiful but also durable and safe for everyday use. Stoneware is a fantastic option because of its robust nature. Fired at high temperatures, between 2,124°F and 2,264°F (1,162°C to 1,240°C), it becomes dense and water-resistant, perfect for dinnerware that can handle the microwave and oven.
Porcelain, with its high vitrification and low porosity, is another excellent choice. Fired at even higher temperatures, up to 2,381°F (1,305°C), it becomes incredibly strong and non-porous, ideal for elegant tableware. While earthenware is more porous and less durable, it can be made food-safe with proper glazing, ensuring a non-porous surface. Clay types can vary greatly depending on the style of pottery you want to create.
“Selecting the right clay is the first step in creating pieces that are not only beautiful but also durable and safe for everyday use.”
When it comes to glazes, selecting the right recipe is just as important. A glossy transparent glaze is a versatile option, enhancing the natural beauty of the clay and any decorations beneath. Recipes typically include silica, kaolin, feldspar, whiting, and zinc oxide, fired at Cone 6 (approximately 2232°F or 1222°C). Satin matte white glazes offer a soft, smooth finish, using ingredients like feldspar, silica, kaolin, dolomite, and tin oxide, also fired at Cone 6.
For a touch of elegance, celadon glazes provide a subtle green tint, allowing surface textures to shine through; these often require Cone 9-10 firing temperatures. For a classic look, Tenmoku glazes offer deep brown to black hues, while Shino glazes bring warm oranges and reds, each providing unique aesthetic qualities suitable for functional pottery. A guide to Shino glazes can show how warm oranges and reds are achieved.
Achieving the right firing temperature is crucial for both the clay and the glaze. Earthenware typically fires between 1,700°F and 2,100°F (927°C to 1,149°C), stoneware between 2,100°F and 2,400°F (1,149°C to 1,316°C), and porcelain between 2,300°F and 2,600°F (1,260°C to 1,427°C). Before glazing, a bisque firing around 1,800°F (982°C) hardens the clay, preparing it for the final glaze firing. Common issues like cracking can be prevented by ensuring even drying and thorough wedging, while warping can be minimized by maintaining uniform wall thickness and avoiding overfiring. Glaze imperfections like crawling and pinholing can be avoided with careful application and proper firing schedules.
- Earthenware: 1,700°F – 2,100°F
- Stoneware: 2,100°F – 2,400°F
- Porcelain: 2,300°F – 2,600°F
These are the firing temperatures for the 3 common types of clay!
Safety is paramount when creating functional pottery. The FDA sets guidelines to prevent lead leaching, and testing is crucial, especially for imported or handmade items. Porous surfaces must be properly glazed to ensure food safety. By following these guidelines, potters can create beautiful, functional pieces that are safe for everyday use, bringing both joy and peace of mind.
