It may sound strange and at the same time obvious to say, but everything that a potter does affects the final product and you don’t know until the piece comes out of the kiln how it will look. The below is the start to finish when a potter makes a pot. I think that this is perhaps more of the case with pottery than anything else. I often say that the personality of the potter ends up on the pot. But let’s look at the process and see how each step affects the final product. Because of the length of this blog I have broken it into sections.
Step 1: Mixing the clay.
This is the dirtiest part of a dirty job. The clay body that a potter uses is a combination of different naturally occurring ingredients: Clay, Silica, Fluxes and Oxides, which affect the color of the body and the temperature to which the clay is fired. Some of the oxides, like iron, are naturally occurring in some clay. Terra-cotta is an example of clay with iron mixed in by nature. I prefer a whiter clay body because it brightens the glazes, whereas a darker clay body muddies the glazes. The optimum amount of water in a clay body is in the 20% range. The ingredients along with water are placed in the mixer and blended until mixed thoroughly. After this the clay is run through a pug mill which further mixes the clay and deairs it. It is stored in plastic bags for use. Before the invention of plastic, clay was mixed in large quantities and kept under a shed a dry shell would develop helping to keep the interior moist.
Step 2: Forming the piece.
There are a variety of ways that a potter can form and piece. The potter can throw a pot on the wheel or hand build with slabs, coils, or press molds. The potter can even slip cast parts and assemble them to create a finished piece. No matter which way a potter chooses to make a piece, this step imprints the potter’s personality on the piece more than any other.
Step 3: Trimming the foot or cleaning the bottom.
The bottom of each piece has to be trimmed or smoothed. This is a process of taking off excess clay or smoothing it to remove any rough edges. When trimming a piece, the pot is typically placed back on the wheel, upside down this time. It is re-centered and wads of clay are stuck down at four points around the pot to hold the piece on the wheel head. As the wheel turns, the excess clay is trimmed away with a tool that has a blade specifically designed for this purpose. Often a foot is carved out of the excess clay on the bottom.
Step 4: Attaching Handles/Pulling Handles
If you are going to attach a handle to a mug or pitcher, it has to be done while the piece is still moist in a state called leather hard. For mugs, we extrude a long piece of clay that we cut into three-inch long pieces. The piece of clay the handle is made from is scored on one end with a fork and the mug part is scored where the handle will be attached. Slip made of the watered-down clay body is brushed on the scoured piece and mug shape. This evens out the moisture content of the two pieces and welds them together. Then the piece is pushed into the mug, forcing an attachment. With water on your hand you begin to stroke the clay, squeezing it slightly as you move from the mug to the end of the piece of clay. The motion, combined with the pressure, thins the piece toward the end and lengthens it. With each stroke you have to turn your hand from one side to the other of the length of clay as you pull the handle because the pressure and shape of your hand causes the handle to be shaped more in one direction than the other, making the handle curve to the left or right if you don’t make adjustments. After you have pulled the handle to the length and shape, you require you press it to the bottom of the mug.