What is Minimum Thickness for Creating Durable Pots?

Choosing the Right Clay

When selecting a clay body for your pot, it’s essential to consider its plasticity, fired strength, and thermal shock resistance. A general rule of thumb is to use a clay with a high silica content (at least 70%) for increased durability. You can also add materials like kaolin or feldspar to improve the clay’s plasticity and fired strength. For a basic pot, a mixture of 50% clay, 20% sand, and 30% silt should suffice.

Coiling and Shaping

To achieve a consistent thickness, use the coil method to shape your pot. Start by rolling out a rope of clay to the desired thickness (about 1/8 inch or 3 mm) and then coil it onto a flat surface. Continue coiling until you reach the desired height, and then use a wooden or bone tool to shape the pot into its desired form. To achieve a uniform thickness, it’s crucial to maintain a consistent coil size and spacing.

Firing and Waterproofing

Once you’ve shaped your pot, it’s time to fire it. For a durable pot, you’ll want to use a pit firing technique, which involves heating the pot in a pit lined with refractory materials like firebrick or ceramic fiber. The firing temperature will depend on the clay type, but a general range is between 1800°F (980°C) and 2200°F (1200°C). After firing, your pot will be brittle and prone to cracking, so it’s essential to apply a waterproofing treatment to seal any pores and prevent water absorption. A mixture of beeswax and linseed oil is a simple and effective solution.