Making pottery clay from scratch may be a time-consuming task but it is well worth the effort. While there are many clay body recipes you can follow to create specific clay, you can also use raw clay that is harvested directly from the ground. The entire task will take four to five days, depending on the humidity and temperature. Free of added ingredients such as grog, homemade pottery clay allows the potter to customize the consistency and color of the clay as desired.
Break clay chunks into small pieces. Spread harvested clay onto a 4 mil plastic sheet. Remove all debris such as rocks and sticks. Let dry.
Place a small bucket of dried clay on another sheet of 4 mil plastic. Fold over the plastic so the dried clay is sandwiched. Break the clay into powder by hitting it with a rubber mallet. Open the plastic and remove any rocks or debris that may be seen.
Sift powdered clay through the medium sifter onto another sheet of plastic. Throw away the pieces left in the sifter. Pour the sifted clay into a bucket. Sift the powdered clay through the fine sifter. Throw away any pieces left in the sifter.
Place the fine sifted clay into a plastic bucket. Add water until there is enough to saturate and cover the dust by ½ inch and mix thoroughly. Put the wet clay (also known as slurry) onto a plaster bat after the water has evaporated from the clay so it is the consistency of thick pudding. Remove from the plaster bat when the clay no longer sticks to your fingers when you touch it. Lay a plastic bag over the clay bat to avoid moisture evaporating too quickly. Store in clay bin.