Method and Process
I've been asked many times what goes into making a porcelain piece. Although there are as many variations in technique as there are potters, this page attempts to address that question. My methods (mad though they may be), invariably add time and effort to the basic process, but I employ them in an endeavor to produce pieces that seem timeless and effortless.
It's not unusual for a piece to take several months to complete. I normally produce about 150 porcelain pieces a year, each one-of-a-kind and signed. I also inscribe each piece with its own number, which I use for tracking the piece through its evolutionary process.
Because my pieces are all wheel-thrown, their evolution begins with conditioning the porcelain clay. Before throwing the clay must be homogeneous, without air bubbles, and the proper consistency; that is, not so hard as to be unworkable and not so soft that it cannot stand up to the rigors of the throwing process. It must also be within the appropriate pH range: a too-high or low pH will render the clay unworkable.
Once the clay is conditioned, I can begin to throw. The throwing process begins by centering a piece of clay on the wheel and making an indentation in the center. From this indentation, a bottom is formed and then the sides of the pot are pulled up into a cylinder over several passes. Finally, the piece is given shape.
The subtleties of throwing are truly infinite, and it's impossible to understand how it happens without having had the experience. People who watch this process for the first time are usually surprised at the dance-like quality of the process, and I can affirm that it feels that way: just as dancers must be sensitive to one another to create something beautiful, throwing is a constant give-and-take between potter and clay. If the potter is not sensitive to the clay, the final piece will reveal that insensitivity. The potter is the leader of the dance and also the choreographer; his or her responsibility is to choreograph the forming in the most elegant way, as extra steps and mismoves affect the piece negatively.
After the piece is formed, it is allowed to dry overnight in a draft free place. As soon as the piece has stiffened enough to be trimmed at all, it is important to begin to take some of the extra clay from the piece, or it will develop an S-crack in the bottom. I trim in several stages over three or four days' time during the course of drying, and I use a variety of tools: some are expensive tungsten carbide trimming tools ($50 each), some are stainless steel and rubber ribs, and some are cheap, everyday objects like single-edge razor blades, which sell for 5 cents each. My goal is to remove all excess clay and to make the surface - inside and outside - as smooth as possible.
All clay has what is called memory (the tendency to return to a shape previously held), and high-fired porcelain has it to a very great degree. I smooth the insides of my pieces because of this memory. (I have found, for instance, that throwing rings left inside a piece will be visible on the outside of the piece after glaze firing, even if the outside surface had been trimmed perfectly smooth before firing.)
The perfectly smooth piece is allowed to dry completely and is then fired to about 1900F, a process called the bisque firing. The bisque has one purpose; to make the clay hard enough to accept glaze without breaking.
I always wash my bisque pots in a large bucket of water to remove all dust. Washing the pots also gives me a chance to closely examine each piece one more time and sand away any small remaining imperfections before glazing.
The pots are now given a coat of wax resist on the bottoms, and any other place where I do not want glaze to stick, such as the galleries of lids and the lids themselves. Since porcelain is so translucent and glasslike, lids fired together with the pot will stick irrevocably unless alumina hydrate is added to the wax, and sometimes even if alumina hydrate is in the wax they can become so stuck that they will not come off without breaking. I now routinely fire the pots and the lids separately, as the pots tend to shrink more than the lids, and I do not wish to take the chance that the lid will stick forever. The result is often a lid which is too large, and that means grinding until it fits.
After the wax dries, the pots are ready for glazing. A pot may require many coats of glaze before the first glaze firing, and I glaze each coat on a separate day. I always pour-glaze the insides of the pots; if the inside requires two coats, the coats are each applied on a different day. Depending on the glazes, I might pour, dip, brush, or spray the outside coats of glaze. I find that it's very important to mix the glaze thoroughly right before applying it.
Because I've formulated all of my own glazes, I know their idiosyncrasies very well. Although it sounds esoteric, a very real part of my glazing process is to attune myself to the nuances of the way the raw glaze coats the bisqued form. I see my role as facilitating the intersection of the two elements - clay and glaze.
Continue Reading About »