Quick Answer
To layer coils in large pottery projects, start with a solid foundation, then alternate directions to build up layers, and maintain consistent moisture levels to prevent cracking. Use a combination of soft and hard coils for added strength. Apply gentle pressure to secure each layer.
Choosing the Right Clay
When working with large pottery projects, it’s essential to select the right clay for the job. A mix of high-fire and low-fire clay is often ideal for large coils, as it provides both strength and workability. For example, a 50/50 mix of terra cotta and ball clay can be a good starting point. Ensure your clay is properly sourced and has good plasticity, as this will impact the overall durability of your vessel.
Building Up Layers
To build up layers of coils, start with a solid foundation of about 3-4 inches in diameter, then alternate directions with each subsequent layer. This will help prevent cracking and ensure even distribution of weight. Use a gentle pressing motion to secure each layer, applying about 1-2 pounds of pressure per inch of coil thickness. This will help prevent air pockets from forming and reduce the risk of cracking.
Finishing Touches
Once your vessel is built up, it’s essential to apply a waterproof coating to protect it from the elements. A natural beeswax or linseed oil mixture is a good starting point, applied in a thin layer and wiped off with a cloth to prevent excess buildup. For pit firing, apply a layer of sawdust or other combustible material to create a carbon-rich environment, which can help achieve a range of colors and textures.
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