Egyptian paste or Egyptian faience is a low-fire mixture of ceramic materials containing clay, sand, colorants, frits, and soluble salts. These salts effervesce to the surface along with water as the paste slowly dries, forming crystals, which create a self-glazing clay-glaze hybrid once fired. Deborah Sigel was intrigued by the properties of Egyptian paste and the opportunity to “build sculpturally with color.” Today, in an excerpt from the Pottery Making Illustrated archives, Mary Cloonan explains Deborah’s interesting process and beautiful results.- Jennifer Poellot Harnetty, editor.
Building Forms with Egyptian Paste
Sigel welds the frameworks for her sculptures from .25 inch steel rod, which can withstand the heat of a low-temperature firing (figure 1). Fabricating her frames in this way gives her the ability to sculpt with strong, bold lines. She sees the forms as a three-dimensional drawing for the Egyptian paste to inhabit.
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Once the frame is fabricated and cleaned up, Sigel dons gloves to protect her hands from the caustic soluble salts and to minimize her exposure to colorants, then packs the forms completely with Egyptian paste (figure 2). Her recipe consists of glass frit, soluble salts, nepheline syenite, clay, and a small quantity of sand to help control shrinkage. She has reduced the amount of soluble salts, substituting in nepheline syenite, to combat the scumming on the surface that’s common with Egyptian paste. Occasionally a small amount of lithium carbonate is added if a slight sheen is desired, so that after the firing, the surface still looks like it did when freshly modeled. Colorants are added at 6–8% in the form of Mason stains, or 2% for metallic oxide colorants. Sigel started her investigations into Egyptian paste with two recipes. As time went on she began to favor Mark Johnson’s Matte Egyptian Paste recipe and made a few modifications including firing higher and lowering the amount of soluble salts. The new recipe may not conform to the standard idea of an Egyptian paste recipe, but the modifications work well for Sigel’s sculptures.
The dry ingredients are mixed with just enough water to create a thick, moldable paste. Sigel then carefully hones the surface, using the spine of the rod as a guide, meticulously smoothing the paste with a soft red Mudtools rib (figures 3 and 4) and a fettling knife (figure 5).
Once the frames are filled and refined, she loads them wet into the kiln and fires them slowly to cone 05 with the kiln lid or door propped open for the moisture to escape. This is a counter-intuitive process for anyone accustomed to the usual firing techniques for Egyptian paste, where it’s dried slowly to allow for the soluble salts to come to the surface creating the self-glazing layer, but it works for producing the surfaces Sigel prefers.
Still, she does find it fascinating that the pieces stay together despite being fired wet, “Why don’t they explode? It baffles me!” Perhaps it’s the openness of the paste body, which contains little clay. Perhaps the cracks form early on in the drying process and allow the steam to escape in a less destructive manner. The combination of firing damp with the incompatible coefficients of expansion between the steel and ceramic materials promotes the cracking and fissures she is seeking, a randomness within the set pattern. Note: You can fire wet. Pots explode in a kiln when the outside dries and traps water inside. As the water turns to steam and expands, it has no way to dissipate, and the resulting pressure causes the pot to break. When firing wet work, heat the kiln slowly. Loading the kiln also influences the final work. Flowers are fired flat on a bed of sand, this supports all the petals while supplying a release in case of over fluxing. Wisps and Bursts are hung in the kiln, in the same position they will be displayed after the firing (figure 6).
Sigel builds brick towers in the kiln with a support rod made of black steel pipe, the kind used for gas lines, that the top loop of the steel armature hangs from. An interesting alteration occurs in the kiln. The Bursts, being a single, centralized point or weight, remain straight. The Wisps start off straight, but the offset placement of the pods distribute the weight and heat differently creating serpentine curves (figure 7). As individual pieces or as a whole installation, there is a quiet elegance and rhythm to their geometry (figure 8). They’re stoic, but there’s also a strong sense of humor; playful colors imply toys and their display cause one to invent games with the quirky implements (figure 9).
For Sigel, the materials are more than just a curious aesthetic result; they become a metaphor for the effects of time. It’s about embracing chance and revelling in the precarious balance of chaos and order. The kiln is an important partner in her creative process, it alters with heat and time, transforms the steel and Egyptian paste, recording history, and endurance. In her work, Egyptian paste and steel are integral and integrated elements, a symbiotic relationship creating controlled serendipity.
Deborah Sigel is a full professor at Millersville University of Pennsylvania in Millersville, Pennsylvania where she teaches ceramics. To see more of her work, visit http://deborahsigel.com.
Mary Cloonan is an artist, instructor, independent curator, and the exhibitions director at Baltimore Clayworks in Baltimore, Maryland. If you’d like to try using Egyptian paste but don’t want to mix your own, check out prepared versions at www.amaco.com and www.lagunaclay.com.—Eds.
**First published in 2014