Vital Earth Skills: Collecting clay and making pots
I have read all kinds of methods for making clay pots, but few articles or videos on First People techniques or bushcraft explain about the clay themselves. It's actually very important to understand, because if you chose good clay, then it will fire better, and you'll have less breakage, and so, let's begin with that.
Clay is a component of soil. We don't know much, but it appears that some clay is self-replicating, almost demonstrating a form of life. Interesting isn't it, because that appears in myths and spiritual systems in many cultures.
Because all soils contains some clay, some are better than others. Usually what happens is because of drainage or lack of drainage, water will pool, and wash out the loam and humus of soil and thins it on the surface. The loam is the rich wonderful soil at the top six inches. The humus is often on the very top, the debris of small natural items that breakdown and then slowly embedded in loam. Rain falls, and as it does all of the harder soil underneath prevents the loam which is less dense to penetrate deeper, and so that layer below the loam l has a higher clay component from the washing of rainfall.
Some soils along river plains will have more clay. More flooding will wash away loam, and so river banks have lots of clay. If we're foolish, or don't know what to do, then we'll look for clay by digging around randomly. We might happen upon a yellow or red clay, sometimes a white clay and then use that. Sometimes the Source just gives a deposit of clay in a meadow or forest, often from a flash flood, and if we use our sense of the Green then we can find it by perceiving its location. This is not common at all for a greenhorn. It would be a blessing regardless.
A far superior way is discussed in the first video. You wash it! What a revolutionary idea, huh? You use the water's natural effect to separate the soil into component layers, and then what settles in the bottom is mostly clay, and therefore precisely what we desire.
If you don't do this, you'll have some sand in it, and sand creates spacers where the clay cannot adhere to itself, and so eventual breakage. Sand is added to clay soil to make it easier to grow crops since you can then plow and make the soil more friable. Looking under the microscope, clay looks exactly like dinner plates stacked. The sand adds more spacers, and so makes it break up, and we don't want any for clay pot material, but we want some for growing crops so the seeds can sprout through it, make roots, drain water, etc. Sand doesn't float, but some will swish out as you wash it.
Almost always you will use the rope clay method and build up layers quickly, but it you don't keep the clay pot-in-process wet, then it will dry at different rates and then potentially break under firing.
Watch these videos to see both how to wash the clay and concentrate it, then follow with the rope clay method to form it into layers and then create a pot. If you had a potter's wheel moving at a uniform speed and perhaps some tools or a sensitive hand, then you smooth the clay better to form thicknesses and mold the clay.
There are several parts of the clay series at both channels and very good bushcraft information on a variety of topics.