The process of preparing the clay is primitive, slow and laborious. What I’m doing here is soaking the clay in buckets of water, then once wet, first by hand picking out the large sones. Then working it through a series of smaller and smaller screens to separate the smaller rocks from the clay. Once clean of all rocks, it goes into a large canvas sling for the water to drip out and evaporate, while I slowly stir it over a couple of days. Then it moves into a large plaster mold, covered in canvas, the plaster pulls moisture from the clay faster than just the air does.From there it moves to the concrete floor in the canvas to further air / dry out. All the while being rolled around in the canvas to make the drying even and the clay body more uniformed. Eventually it becomes dry enough to handle. In the case of these photographs, there are three different clays being processed (150 lbs of each), then once they are cleaned and dry enough, they are combined into one clay body by piling them on the floor and walking on them to wedge it all together. Then it is run through the pug mill to further mix / combine the clay and remove more of the air. Then last it is wedged by hand. And then it is finally ready to try to use to make pots. It took about three weeks to process the first 400 pounds of usable clay, from about 450 pounds of dry clay. You lose some weight from rocks being removed and gain some weight from the addition of water. Clay number 5 has a lot of rocks, as you can see in the photos, so 150 pounds of dry clay yielded about 100 pounds of clean, wet clay. Clays 2 and 3 were equal in weight after the removal of rocks and addition of water. You can also see from the photos below that each of the three clays has a different color. Each was harvested from a different location and depth on the site.
Here is a little video about the clay “making” process.