Bill Sax is a full-time studio potter specializing in functional ware. He makes cookware, sinks, tabletops, decorative production pieces, wall, floor and countertop tiles from clay. He is one of only a handful of potters in the country producing clay vessels that can be used over direct heat, known as flameware.
Bill started out studying printing at Rochester Institute of Technology (RIT) before volunteering for a two-year stint in the U.S. Army during the Korean War. On release from the army, he returned to Rochester to finish his B.A. He became intrigued with pottery after passing by some of the university’s studios, where students, rapt in concentration, were molding clay objects with their hands. With an extra year of college provided for by the GI Bill, he stayed on in Rochester to learn the craft.
After receiving a MFA in pottery from the School for American Craftsman at RIT, one of the country’s finest ceramics programs, Bill apprenticed under the program’s guiding force, Frans Wildenhain. German-born and Bauhaus-trained, Wildenhain was one of the seminal figures in American pottery, known for both his masterful teaching and art. Through his instruction, Bill learned the technical aspects of the craft as well as a strong sense of discipline in thinking about and working with clay.
Today he continues to make pottery as he has since 1954. He has taught at Boston University, the Boston Museum School and Mt. Holyoke College. His work can be found in fine craft stores around the country and by appointment at his showroom in South Hadley, MA.
Inside the Studio
CLAY BODY TYPES
Clay is more than clay. The material used to make a ceramic pot is a composite of different clays and other mine materials called a “clay body.” I work with three types: stoneware, porcelain, and flameware. All three are high fire clay bodies, meaning that they are fired at high temperatures (2250°-2350°C) until vitrification-the process by which the clay’s silica particles fuse together to form a glassy structure. There are other types of clay bodies, namely the low fire earthenware, but I prefer the heft of high fire clay bodies and the types of glazes that work with them.
STONEWARE is dense high fire clay body that becomes nonabsorbent and nonporous after being fired. Stoneware, so named for its rock-like constitution, fires to gray, tan and brown and tends to darken glazes.
PORCELAIN, a variation of stoneware, is made with the light kaolin clay, but without any iron. In the absence of iron, which renders clay a brownish hue, it is translucent white. Light and less reactive with glazes, porcelain shows a wide variety of glazes and bright colors.
FLAMEWARE is another variation of stoneware, but made with lithium, which reduces the expansion of a fired pot during temperature changes. Most fired pots will expand and contract when exposed to wide temperature variations, resulting in cracks, but these pots can be used directly over heat sources for cooking. During firing, lithium will react with and darken many glazes, which greatly limits the number of glazes and colors one can use on flameware.
THE PROCESS OF MAKING A POT
Making a pot varies by piece, purpose and potter. For me, it is essentially a six-step process: mixing the glazes, mixing the clay, forming the object, bisque firing, glazing and glaze flaring. Two of the steps – mixing the clay and mixing the glazes – are done in large batches and so do not need to be performed each time a pot is made.
MIXING GLAZES – A ceramic glaze is a coating used for decorative or functional purposes. The base of most glazes is silica, or glass, which is mixed with a variety of other chemicals that are chosen for color, texture and shrinking rate that they express when fired. I mix 5-7 gallons of glaze at a time, making more as needed. I have a few standard glazes that I’ve been using for years and I come up with a new glaze every so often after a few months of testing. In fact every firing will have a few new glaze tests within. Always seeking new glazes
MAKING CLAY – I mix various raw clay powders to achieve the desired balance of different characteristics – strength, color, workability (plasticity), appearance, and firing temperature. Making a clay body is somewhat similar to making a cake batter. Each has a recipe card with ingredients and amounts. Dry ingredients, such as raw clay powders, are combined with water in a clay mixer, which is somewhat comparable to a standing dough mixer. When making a clay body, I make three 250 lb batches for a total of 750 lbs of ready to use clay; this will keep indefinitely if properly wrapped, but I typically use that amount in a month.
FORMATION OF THE OBJECT – Forming an object out of clay, referred to as “throwing” when done on a wheel, is the art of pottery. Each pot and each plate is an idea. Some are new ideas, inspired by the moment, and others are old ideas, worked on for years or borrowed from friends, a living legacy of their memory
BISQUE FIRING – After pots are formed and dried, they are fired at a low temperature (1700°C), called bisque-firing, before being glazed. Unfired pots will absorb the glaze and the added moisture will soften the pot and distort its shape. Bisque firing hardens the clay to the point at which it will no longer absorb glazes, but glazes will still adhere. IF the pot is fired for too long, it becomes nonporous and the glaze will slide off its surface. I bisque-fire my pots for 8-10 hours and then allow them to cool for another 8-10 hours in the kiln.
GLAZING – Once the pots are bisque-fired and cooled, they are ready to be glazed. I wax the parts of the pot that I do not want to be glazed, such as the bottom, which if glazed will fuse to whatever it is touching. Then dipping, pouring and brushing, I will add glaze to create the desired effect and allow it to dry before glaze firing.
GLAZE FIRING – Once the kiln is filled, the temperature is brought up steadily and evenly to about 2350°C. I glaze fire my pots for 20 hours and then allow them to cool for an equal amount of time. During this period, the clay hardens further becoming vitrified as the glaze hardens and welds onto the pot. Now the clay body is vitrified and waterproof. Glazes in themselves are not waterproof. Work cycles vary by kiln size, work rate and potter. My work cycle, or the time it takes to throw, form, trim dry and fill a kiln is approximately one month, depending on the season and how much gardening is called for.
COOKING IN CLAY
Humans have been cooking in clay for thousands of years. The earliest evidence unearthed fragments of ceramic cooking vessels, dates back to the Neolithic Era. Today many clay pots hold special places in the cooking traditions of their indigenous cultures. The Moroccan tagines, Chinese sha bao (sa bo in Cantonese), Spanish cazuelas, Thai mor din, and French poêons are just a few.
While I was studying ceramics at the School for American Craftsmen, I came across the beautiful and very honest work of celebrated potter Karen Karnes. Most notably she made a variation on stoneware that could be used over direct heat, what she called flameproof. Traditional clay cooking pots were made of earthenware. As far as I know, no other potter was making flameproof stoneware at the time.
These flameproof pots, their beauty, strength and multi-functionality, were immediately appealing. At the time, Corningware oven safe-pots and ceramic cook tops were on the market, and ceramic tiles that could withstand incredibly high temperatures were used for thermal protection on spaceships. I started leafing through industrial reports and trade magazines to learn more about the industrial uses of clay and then started experimenting with different clay bodies. After months of testing back in 1954, I came up with a recipe that worked and since then I’ve been making ceramic pots for booking, which I have dubbed, “flameware.”