Stoneware Clays

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Sajo Ceramics has a wide range of stoneware clays and glazes to choose from. We stock Feeneys, Walker Ceramics and Keane brand clay bodies as well as Cesco and Mayco glazes.

Stoneware is a vitreous or semi-vitreous ceramic made from stoneware clay or non-refractory clay. It is nonporous and will not soak up water whether vitrified or not. It is fired at higher temperatures than earthenware.

Typically, stoneware is fired 800 degrees Celsius for bisque firing which burns out any organic impurities within the clay body. This firing creates a more durable surface to work with when moving on to the glazing stage. Glaze firing temperatures range between 1180 – 1280 degrees Celsius in order to allow the glaze to mature. Glazing colours are more limited at stoneware firing as certain pigments and oxides burn out at certain temperatures.  Depending on Flux content, stoneware can be fired at temperatures varying from 1100 to 1300 degrees Celsius if desired.

There are five basic stoneware categories – Traditional stoneware, Fine stoneware, Chemical stoneware, Electrical stoneware and Thermo Shock Resistant stoneware. The main types of stoneware used for potters and ceramicists are traditional and fine stoneware clay bodies.

Stoneware can be once fired or twice fired depending on what finish the potter is after. If fired once, there is a greater risk of breaking during glazing and then through the firing process.

Stoneware comes in many colours and textures ranging from smooth to grainy, greys to darker tones. There is a wide variety of textures to choose from when considering the aesthetic of the piece in which the potter is after and these clay body textures react in different ways when different types of glazes are applied to the surface.

It is best to always do tests for your glazes at different temperatures, on different textures and types of firing before applying that glaze to your piece. Potters use test tiles, or small cylinders thrown on the wheel to test the way the glaze will behave on a particular clay body.