Additions to Clay Bodies: Metals Kathleen Standen

Appears in the Nov/Dec 2015 issue of Pottery Making Illustrated.

Nichrome wire, steel rods, mesh, copper and steel wire, nails, tacks, and recycled metals have all been added to clay bodies by ceramic artists. Sometimes, the metal is chosen for support, sometimes for interest, and frequently a combination of both. But a good match between the clay and the metal must be found, because metals melt and lose their strength at different temperatures.

Linda Hansen Mau: Metal Connections

An interest in the science of materials, how they behave both separately and in combinations, is how Linda Hansen Mau describes her journey, culminating in her present work: layering paperclay slip onto a steel armature and joining clay slabs using only steel nails or rods.

Mau begins by drafting precise paper patterns of the design. Then, wearing leather gloves, she follows the patterns to cut ½-inch sections of steel mesh with metal cutters. The seams are joined with wire, resulting in the finished shape in metal.

The next stage is to coat the wire armature, either by brushing or pouring, with paperclay slip. Each coat of slip is dried completely before the next layer is added, a process that can take several days. Mau chooses to use cotton linter in her paperclay because it lasts longer, with a reduced risk of it starting to rot and smell. She combines it with porcelain in proportions of 20% pulp to 80% porcelain. Knowing how many layers of slip to apply is gained by practice and experience: too few layers and the work lacks strength due to insufficient clay remaining when the fiber burns away.

Before firing, the steel mesh provides the form with strength, but after firing in an electric kiln to 1900°F (1038°C), the steel becomes brittle and it’s the clay that gives strength to the form. A final slip layer is either a white or a red terra sigillata. Further color options are introduced by smoke firing the bisque pieces with newspaper in an open metal container, followed sometimes by an application of paste wax or shoe polish, and light buffing to encourage a sheen on the surface (1).

For her Clay and Nails series, Mau added vermiculite to stoneware clay. The resulting slabs were then textured by pressing in wood, stones, or seed pods. These slabs are then joined using only steel nails to form various functionally-related objects, such as teapots (2). The juxtaposition of a familiar object that cannot function is part of the fun Mau derives from this work.

Susan O’Byrne: Support System

The first time I saw one of Susan O’Byrne’s life-size sculptures, I was in awe of the unique way she builds a metal skeleton, which she covers with a skin of clay and imagery to depict everyday animals of the English countryside (3 and 4).

O’Byrne’s large animals begin with a nichrome wire framework (nichrome can withstand high kiln temperatures). Onto this framework she applies thin layers of stoneware paperclay. The paperclay helps to strengthen the work before the application of more fragile layers of porcelain paperclay. The final layers of clay are patterned and colored using various printing, drawing, and stencilling techniques. The thin sheets of clay are made by pouring slip onto plaster bats. Once decorated and dry enough, the clay is peeled from the plaster and collaged onto the animal.

Elements of chance, the natural twists and kinks of the wire, and the shrinkage of the clay around it during firing are allowed to contribute to the posture of the finished animal, a process that gives O’Byrne’s animals an awkward vulnerability.

Lesley Risby: Curved Framework

Organic, skeletal, fragile, and vulnerable are words used by Lesley Risby to describe her ceramic forms. Her choice of words is apt: a nichrome wire frame is fashioned into a sinuous curve, covered with fabric and porcelain slip, and then subjected to intense heat that causes partial disintegration. She likens this process to the susceptibility of living organisms to environmental forces, whether natural or man-made.

The initial design of the form is produced with a clay/wire maquette or a sketch. From this idea, a model is handbuilt using crank clay (clay with lots of grog in it so it’s less likely to shrink, warp, or crack during drying), painted with kiln wash, and fired to cone 7 in an electric kiln. The model is needed to support the metal framework during the firing, otherwise it would collapse.

Risby then weaves a nichrome wire form to fit the model, using three gauges of wire (0.56, 0.9, and 1.2 mm) (5). Porcelain casting slip (containing finely chopped fabric to help the slip adhere to the wire; 200-mesh molochite to help reduce shrinkage; silicon carbide for texture; and oxides and stains to add color) is brushed onto the wire form to build it up (6). She then adds more coats of slip containing 3% black copper oxide and 3% silicon carbide. Finally, two or three coats of a brush-on, semi-transparent glaze are applied.

She fixes the piece over the model, then onto a post (7) using more nichrome wire and fires to 2228°F (1220°C) with a 30-minute soak. Crank clay barriers are placed around the work to protect the kiln elements from the clay that spits off the wire during the cooling process. Ultimately the fired framework cradles several lightweight, press-molded, porcelain cups (8).

Deborah Sigel: Steel Structure

Deborah Sigel has combined her interest in mathematics and design in the creation of abstracted flower-like forms. Her choice of materials was guided by a desire to work sculpturally with color and she quickly discovered the potential array of brilliant, candy-like colors that could be achieved using Egyptian paste. Other advantages are its single firing and low-temperature properties, which are ideal, as she fills a steel framework with Egyptian paste before firing (see PMI March/April, 2014). The use of a steel framework came out of a need for a supporting structure to hold the self-glazing Egyptian paste up off of the kiln shelf.

Sigel uses hot-rolled, mild steel, which is welded together to form a pod-like frame. She then fills the steel pod forms with colored Egyptian paste using a fettling knife, rubber ribs, and a sponge (9). She works the paste to create a smooth surface, free from blemishes. It’s important that there are no distractions on the surface to detract from the desired shrinking and cracking that occurs during the firing. Her forms are then suspended inside the kiln by threading a premade loop over a steel pipe, which rests on brick columns (10). Sigel says that firing speed, temperature, and gravity all affect the final outcome of her work. Sigel notes that the unpredictable nature of the steel and the Egyptian paste is part of the attraction of working with them together (11).

Metal Additions for Interest

Wild leaping hares, solitary doughty bulls, a decaying brace of pheasants, birds on the wing, performing monkeys: these are just a few of the sculptural creations by Emma Rodgers, whose imagination is captured in clay, glaze, and found metal objects. From movement and tension to stillness and tenderness, she peels back the layers of existence, leaving just the essence of what it is to be alive or dead.

Rodgers’ willingness to experiment has led to combinations of materials that don’t easily fit into any well-established genre. Some of her found materials include: mattress coils, the innards of clocks, and nails just to name a few.

Bull (12) was made with porcelain clay mixed loosely with Earthstone clay, into which metal nails were inserted before firing. The nails add interest to the composition, representing horns and shin bones. The sculpture was fired to 2084°F (1140°C) with a 20-minute soak. The low temperature, combined with a soak of this length, conveys strength to the form, with a reduced risk of warping. Small gaps are left around the metal insertions to allow for shrinkage of the clay, thereby avoiding unnecessary cracks.

Glazes or slips were applied before a second firing to the same temperature and soak. This procedure may be repeated a third time if adjustments to the final color are desired. Occasionally a fourth luster firing is carried out on some pieces. Rodgers emphasizes that this repeated firing regimen strengthens the work, in the same way that a higher firing would, but without distortion.

The Tower, Forward 11, Orbit: these are the titles of Deirdre Hawthorne’s trademark cylindrical beakers, which are pierced by numerous metal tacks and staples, as well as imprinted with textures (13). She acknowledges that these techniques not only push the clay almost to the point of destruction, making it fragile, but also reveal its inherent resilience. Each piece is fired in a sealed saggar to 1994°F (1090°C), with various combustible material.

Todd Leech uses electric kiln elements to create forms representing the human body (14). Leech drills holes into clay forms when they’re leather hard, then inserts recycled kiln elements. He applies specially formulated glazes that reach and spread across these metal elements, replicating human tissue regeneration. He says, “I am endlessly fascinated and inspired by the body’s ability to repair itself.”

Leech says that a reduction firing to 2340°F (1282°C) produces the best results, as the foaming of the glazes is most impressive. About 50% of the work is also sand-blasted to reveal some of the underlying structure.

Tip: Melting temperatures for common metals: aluminum 1218°F (659°C); silver 1762°F (961°C); bronze 1832°F (1000°C); gold 1945°F (1063°C); copper 1981°F (1083°C); stainless steel 2485°F (1363°C); iron 2800°F (1538°C).

Caution: Clay with metal additions should be fired in a well-ventilated area. Tests of all metals should be done before adding to work.

Excerpted and adapted from Additions to Clay Bodies by Kathleen Standen. ©Kathleen Standen, 2013. Copublished by Bloomsbury Publishing, London, and the American Ceramic Society, Westerville, Ohio. Available in the Ceramic Arts Network Shop.