Cranberry, 4½ in. (11 cm) in height, Grolleg porcelain, shino and ash glaze blend, reduction fired to cone 10, 2010.
For the last few years, I have particularly enjoyed making porcelain cups. I have always searched for ways to make the thrown cup forms more interesting, and by faceting and stretching the cylinders, I am able to achieve a livelier more engaging form. As my porcelain cup forms progressed, they were enhanced with blends of cone 10 shino and ash glazes that reveal a wide range of color and texture as the layers of glaze broke over the surface.
Recently, I relocated my studio and I have quickly come to terms with re-evaluating the direction of my work with a host of new limits. Budget, accessibility of materials, and equipment are the areas that top the list. Relocation has also helped me to position a developing concern for the ecological impact that potters have. With a new awareness, I have embarked on a journey to create a palette similar to my cone 10 work at a much lower temperature. I wanted to retain a dense, durable, white body that would be functional with glazes that would reinforce the dramatic faceted tactile surface in a manner similar to high-fired shino and ash glazes.
Origins of Fritware
History shows us that in the 9th century CE Islamic potters faced a similar dilemma when they were introduced to the visual and tactile qualities of the Chinese porcelain that was being imported into their area. Islamic potters did not have the raw materials, knowledge, or technology to make porcelain, but with the materials available in the region, they developed fritware as a way to assimilate the visual and tactile qualities of Chinese porcelain. Fritware was first developed in its earliest forms in Iraq. From there it spread to Egypt and other parts of the Islamic world. Fritware is a clay body that consists mostly of silica with a small amount of clay and frit. Frit refers to a glass or glaze that is poured into water upon being removed from the kiln while it is still hot. When it hits the water, it shatters into tiny pieces and these pieces are then ground up for use as a flux. Fritware is very different from porcelain, but it does provide a dense, bright, white background for surfaces.
Working with Fritware
Not all clay bodies are suitable for the techniques I use to make this type of work. The fritware recipe I have developed takes both workability and budget into consideration. Even with this recipe I have found that attention to detail is key. Having the correct moisture level and curing time are critical to allow for the clay to stretch so drastically without tearing or slumping over while working on the wheel.
After wedging the clay thoroughly, I immediately sit at the wheel and begin working. I have found that the clay is more elastic if I eliminate the time between wedging and centering. In other words, I am no longer able to wedge up several balls of clay before sitting at the wheel. I wedge enough clay for one piece at a time, no matter what the size may be.
Once the clay is centered, I begin by opening the center with one pull, then immediately begin moving the clay upward until I have a tall, slender, thick-walled cylinder. After horizontally marking the start and the finish lines of my pattern area, I begin faceting the cylinder with diagonal cuts from the top line down and then from the bottom line up (1).
After completing the faceted pattern, I make a double line just below the rim as a way to separate the pattern from the rim. This double line also remains parallel to the rim, which becomes wavy as I stretch the form. This gives the piece a sense of completeness by capping off the energetic undulations created by cutting and stretching the cylinder (2).
My outside hand remains at the wheel head, so I do not disturb the freshly cut pattern on the walls of the vessel. My inside hand enters the small opening gradually as I begin stretching the top section of the cylinder before stretching the bottom section (3–4).
1. After horizontally marking the start and the finish lines of the pattern, begin faceting the cylinder with diagonal cuts from the top line down and then from the bottom line up.
2. After completing the faceted pattern, make a double line just below the rim as a way to separate the pattern from the rim. This double line also remains parallel to the rim, which becomes wavy as the form stretches.
3. The inside hand enters the small opening gradually and stretches the top section of the cylinder before stretching the bottom section.
In order to retain the freshness of the undulating rim, I trim my pieces on a mound of centered clay. I shape this clay into a cone by and paddling with my hands. As the wheel slowly rotates, I gradually work the clay up into a cone shape that will fit inside my piece and provide the support the piece needs in order to be trimmed, while keeping the undulating rim intact. Once I have trimmed away the interior and exterior of the foot (5), I create undulations in the foot ring to reinforce the design feature of the rim (6). The final wet-stage touches are made when the piece is flipped over on its freshly trimmed foot and pushed down a bit with the palm of my hand so the foot ring is pushed up into the base of the piece, which allows the form to assume a more organic posture.
Faceting and stretching a cylinder allows me to match the organic form with the visual color and texture. The images of finished pieces and the glaze details at left are examples of this connection between form and surface, and clay and glaze. All of these glazes were created with one base glaze that is extremely low in alumina, which yields more saturated colors as well as a lower melting point in the glaze. This work was fired to cone 04 with a 30-minute hold at peak temperature. However, I plan to experiment with holds at certain temperatures as the kiln cools as an effort to expand the textural qualities in the glazes.
Clay and Glaze Formulas
The base glaze recipe and colorants for each of the glazes shown are included for you to experiment with. If you do so, I hope you will share your findings with me and/or the larger ceramics community.
While white fritware is more difficult to work with than most clay bodies, it does reveal the lively color and texture of my glazes. Grolleg is the best option for a kaolin source, but with the cost being more than twice the cost of most other kaolins, I began to look into blending other kaolins in order to get similar whiteness, workability, and shrinkage. I ended up choosing an equal-parts blend of EPK and 6 Tile kaolins as a substitute because of their complementary qualities of whiteness and plasticity, as well as the more affordable price. Ferro frit 3124 is a fairly common body frit and is less expensive than most frits available to potters. It vitrifies the clay body at cone 04, though the body could be a brighter white and more translucent with a different frit. It reveals translucency only when thin, so if translucency were my primary goal (and budget wasn’t a concern), I would certainly be using a different frit. I have found the difference between white and bright white can only be noticed when the two are side by side, so at this point, I am satisfied with the working properties and dense whiteness of this body to achieve a more organic unity of form and surface.
the author Frank Krevens is a ceramic artist-educator living in Phoenix, Arizona. He has taught and exhibited studio ceramics since earning an MFA from the University of Dallas in 2010. To learn more, visit www.frankkrevens.com.