Quick Answer
Good clay for pottery making can be identified by its plasticity, strength, and ability to be fired at low temperatures without cracking. It should be free from contaminants like rocks, plant material, or other debris. When wet, the clay should hold its shape without crumbling.
Sourcing and Testing Clay
When searching for clay, look for areas with high concentrations of glacial deposits, riverbeds, or areas with high clay content in the soil. Collect small samples and mix them with water to create a workable consistency. Test the clay by performing a simple plasticity test: create a small ball and roll it into a long rope. If the rope breaks cleanly without crumbling, the clay is suitable. If it breaks or crumbles, the clay is too brittle.
Analyzing the Clay’s Composition
Examine the clay’s color and texture to determine its composition. A high iron content will create a reddish or brownish color, while a high calcium content will create a white or cream-colored clay. Test for contaminants by mixing the clay with water and observing its behavior. If the clay produces a lot of mud or sediment, it’s likely contaminated with plant material or other debris.
Preparing the Clay for Pottery
To prepare the clay for pottery making, mix it with water until it reaches a workable consistency, similar to that of thick mud. Knead the clay to remove any air pockets and make it more pliable. For the coil method, divide the clay into small sections and roll each one into a long rope. To achieve a waterproof glaze, apply a thin layer of natural wax or beeswax to the finished pot and fire it in a pit at a low temperature, around 900°C, to create a non-porous surface.
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