I have found that I enjoy some clay bodies, and some not as much. A clay body can be selected for various reasons, such as texture/feeling, colour (of the clay itself, or how glazes look on the clay body), heat threshold, price, and even shrink rate. Clay is heavy, and typically incurs high shipping rates to arrive at an artist’s studio.
I have several designs and standard pieces that I make, and I have arrived at these measurements, colours, and options over a lot of experimentation, thought, and prototypes. For example, I know that my clay shrinks at a specific range in percentage throughout the process, but the range still allows for a margin of error. This range is determined by heat in the firing, and amount of added water to clay, typically used in unspecified amounts in the throwing process. The final sizes of pieces, especially vessels with specified volumes, must have some margin of error.
For the making of a vessel or ceramic piece, it goes through 3 main stages: Raw clay becoming greenware, fired to become bisqueware, then fired again to become a finished piece.
Clay is manipulating through wheel throwing, handbuilding, or casting. I wheel throw most of my vessels, and handbuild other objects.
For throwing, pieces are made through centrifugal force and water as a lubricant to smoothly create a symmetrical, basic silhouette or profile. This piece is then dried to a stage called leather hard, and trimmed and/or finished. This stage is where any additional manipulation should be done, including options such as handles, stamping, texturing, and dimples/warping. Drying speed is important and must dry evenly to minimize undesired warping.
For handbuilding, pieces can be made in many ways. Most of my handbuilt pieces are made with slabs (sheets), draped on a mold when the clay has a certain malleability. Drying large and flat pieces can be tricky, as the surface it dries on must be completely flat, as well as slightly porous to help the bottom (touching the surface) dry at the same rate as the top. Cracks can form, or warping can happen at this stage very easily.
Up to this stage, the piece is called greenware, and as it dries further becomes bone dry, typically over several days depending on relative humidity, temperature, and airflow. It is then bisque fired in a kiln, to 1000C, or 1800F, over an 8-12 hour period, plus cooling time of another 8-12 hours. Bisque firing is to help it become more durable and hard, yet still porous and in a semi-vitrified state. After a piece is bisque fired, it is ready to absorb glaze. One extra step that can happen here is sanding, which can help improve the final smoothness of the texture. Once a piece is complete, because it is harder and fully vitrified, sanding becomes more difficult to remove material. After bisque firing, the piece can be considered bisqueware.
Bisqueware is finally wiped down to remove any unwanted specks and impurities to provide a clean surface for glazing. Glazes are similar to paint and can be applied in many ways to a piece. However, glazes are made up of specific metals and chemicals (such as chrome oxide, bentonite, copper carbonate, or soda ash), and “recipes” are developed by artists and chemists who experiment extensively. Glazes can be tricky as they are specific in how they react under different conditions – they are sensitive to various heat levels (pieces can look different based on where they are situated in a kiln’s hot spots), as well as application, viscosity (runniness), and whether a glaze is simply evenly mixed. Glazed bisqueware can then be placed in a kiln for glaze firing, typically to 1200C, or 2200F, over another 10-14 hours, plus 10-14 hours of cooling time.
Once everything is finished, I inspect every piece for any issues, and prepare them for any photography required, measurements, and then pack them up when they get ordered!
When a kiln heats clay/greenware for the first time to become harder, resulting in no water that is chemically bonded.
Pieces that underwent a first stage of bisque firing.
Pieces of "raw" clay that has dried out completely, and is non-malleable, brittle, and fragile.
When a clay slurry (slip) is poured into a fixed negative mold, to create a consistent positive form.
The type of "raw" clay that is used. Some have grog/sand blended into the clay, or stains to colour the clay.
When bisqueware gets coated in glaze, and then put into a kiln to become a finished ceramic piece.
Similar to paint, but made from various chemical compounds and metals to withstand high temperatures, and chemically convert into a glassy surface/coating.
Describes clay that has been shaped but not bisque fired yet.
When clay objects are constructed by hand, rather than through methods such as casting or wheel throwing (centrifugal force).
Describes the state of clay where it is slightly malleable but retains structural integrity.
Smoothing or polishing a surface to alter texture.
The amount of contraction/compacting (usually in percentage) that clay pieces undergo upon firing in a kiln.
Rolled sheets or slices of clay.
The act of shaping clay using a wheel and centrifugal force to create symmetrical objects, usually powered manually (via a foot kick) or electrically.