ceramic artsdaily.org clay workshop handbook knowledge and techniques for the studio

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1 ceramic artsdaily.org clay workshop handbook knowledge and techniques for the studio

2 Clay Workshop Handbook Knowledge and Techniques for the Studio Welcome to your workshop! Whether you enjoy throwing, handbuilding, glaze testing or all of the above, we ve pulled together several things for you to try out once you get back to your studio. If you re familiar with Pottery Making Illustrated and Ceramics Monthly, then you already know they re packed full of practical information, projects, and techniques you can use. The articles in this 2014 Clay Workshop Handbook provide a sampling of some of the great content you ll discover in each issue. In addition to our magazines, you ll also find a wealth of information on our website Check out hundreds of free posts filled with tips and techniques and scores of videos providing demos from truly talented potters, as well as our magazine, book, and DVD selections. Flowerbrick: From Clay Body to Form Joan Bruneau Discover how Joan Bruneau applies her interests in history, architecture, and food using a local clay and low-fire polychrome glazes. Ornament Beneath the Surface A. Blair Clemo Add ornament to your functional forms by combining sprig molds and throwing techniques. Softening Form with Color Angelique Tassistro Try this washing technique to create softly layered patterns using layered underglazes. Big Platters the Easy Way Yoko Sekino-Bové Learn the secrets to throwing large platters using more brain than brawn. Cone 6 Glazes Paul Donnelly Check out these cone 6, transparent, glossy and white glaze recipes for functional pottery. Detailing the Surface: Incising and Resist Techniques Doug Peltzman Find out how to use wax and latex resist with incised lines to create some advanced surface techniques. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 1

3 Flowerbrick: From Clay Body to Form by Joan Bruneau Clay I mix my earthenware clay body using 60% Lantz clay, which is mined in Nova Scotia by the Shaw Brick plant. Lantz clay is a unique earthenware for a couple of reasons: it is very plastic and is very tight at cone 04, which means there are no fluxes added to the clay body. I amend my clay body by adding EPK kaolin, OM 4 ball clay, and Red Art clay to raise the maturation temperature and 9% kyanite to reduce the potential for dunting. Professors Homer Lord and Walter Ostrom introduced a Lantz clay body at the Nova Scotia College of Art and Design in the 1970s and a number of potters in the area now mix their own versions of it. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 2

4 Building My oval flower bricks are assembled from wheel-thrown parts. The lids are assembled from thrown rings, cut to form arches that function as a partition, housing flower stems in various positions. To create these forms, I stretch a bottomless cylinder and join it with a thrown and stretched slab disc to form the base. I throw a foot ring separately then attach it to the base. I start the lid by making the flange first, then building up from there. The lid flange is a double-walled thrown ring with a groove thrown in the center. The first course of arches sets into this groove (see figure C). In the end, every part of the flower brick, even the florets and finials, are thrown and assembled. Clay pine cones, rotting pears, and rosettes are formed from small knobs that are thrown off the hump and are incised with concentric rings. These rings are manipulated using a rubber-tipped tool to create the various shapes (A). Pulled twigs and thrown arches are set aside until leather hard and then assembled on the lid flange (B D). Decorating I coat the surfaces with brushed white slip, incise sgraffito patterns, then apply underglazes and polychrome food-safe glazes. First, two coats of white slip are brushed on the leatherhard body. I design and cut my stencils out of regular printer paper. The stencils ensure symmetrical and uniform repeating patterns that enhance the forms. The stencil is traced with a soft 6B pencil on stiff leather-hard slip (E) after the pattern is mapped out on the form first using a ruler and stencils. Then the pattern is incised using a Kemper sgraffito stylus (F G). A copper carbonate wash (see recipe on page 6) is brushed over all of the sgraffito lines using a thin, fine brush. The copper carbonate will later fuse and move as the glazes melt for the desired juicy surface. The gallery and the bottom of the lid remain unglazed (H). A B C D E F G H Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 3

5 Joan Bruneau s polychrome glazes 1 2 JACKIE S SATIN MATTE Glaze Cone 04 Gerstley Borate % Lithium Carbonate Nepheline Syenite EPK Kaolin Silica % Add: Tin Oxide % (or Zircopax %) Colorant Additions: Blue: Copper Carbonate % Cobalt Carbonate % Turquoise: Copper Carbonate % Mottled Tan: Black Iron Oxide % Mottled Peach: Rutile % Yellow: MS #6404 Vanadium % Chartreuse: MS #6236 Chartreuse % Whiting % This glaze is not safe for surfaces that come into contact with food. Add 5 10% whiting along with stains that need the presence of calcium to enhance color, ie: Victoria Green Mason stain, Chartreuse Mason stain, or chrome-tin pinks. Note: MS refers to Mason stain when used within recipe additions. DEB S CLEAR BASE Glaze Cone 04 Ferro Frit % Ferro Frit EPK Kaolin % Colorant Additions: Butter Yellow to Bright Yellow: MS #6464 Zirconium Yellow % Honey: Burnt Umber Stain % Moss: Copper Carbonate % Burnt Umber % Turquoise: Copper Carbonate % Blue: Copper Carbonate % Cobalt Carbonate % Teal: Copper Carbonate % Chrome Oxide % This glaze is transparent, shiny, and very responsive to stains and oxides. To achieve a transparent clear, apply thin. Use a thicker application with colorants for a rich, translucent glaze. Copper Carbonate Wash Cone 04 Ferro Frit % Copper Carbonate % Add a mixture of CMC gum and water to form a wash Flower brick detail, 8½ in. (22 cm) in length, base: Deb s Clear Base over cobalt sulfate decoration, lid: Jackie s Satin Matte Glaze in chartreuse. 2 Savory Platter detail, 17¼ in. (44 cm) in diameter, glazed with Deb s Clear Base in honey, teal, and moss. 3 Salty Platter, 17¼ in. (44 cm) in diameter, glazed with Deb s Clear Base and Jackie s Satin Matte Glaze over black underglaze. 4 Crocus Bowl and Plate Set, glazed with Deb s Clear Base in yellow, teal, and clear over copper sulfate decoration. All pieces are wheel-thrown and assembled Lantz (Nova Scotia) earthenware with slip, polychrome glazes, terra sigillata, Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 4

6 Ornament Beneath the Surface by A. Blair Clemo There are only a few moments I can pinpoint in my life as a maker that have made me take pause, look at my work, and question it all the way down to its core. One such moment came by way of a simple mental exercise put forth by James Trilling in his book Ornament, A Modern Persective. Trilling states ornament is separable from the functional shape of the object. If you want to know whether a particular feature of an object is ornament, try imagining it away. If the object remains structurally intact, and recognizable, and can still perform its function, the feature is decoration, and may well be ornament When I applied this exercise to my work, I noticed right away that so much of the labor I invested could be defined as such. My studio practice, and in fact the education system that I learned from, followed one simple mode of operation; ornamentation comes after generating a form, it is a secondary process. This identification of ornamentation as a subsequent process itself does not trouble me, until Trilling continues, Under the laws of modernist aesthetics, ornament bears damning witness against itself. If we take it away, physically or in imagination, the shape and function of the object are intact. Ornament is unnecessary. My studio practice, at that time, centered on wheel throwing as a way of generating forms. I would sit down with a ball of clay and manipulate that clay into a utilitarian form, something that could be generically described as a vessel. This object would be clean, precise, and unadorned. By the laws of Modernist aesthetic that Trilling mentions, I could be finished at that point. I had made an object that, once glazed, would perform a utilitarian task just fine, perhaps even better than if it were ornate. From that vantage point, there was no actual need to invest more time and energy in my work. Jar, 8½ in. (22 cm), red stoneware, fired in oxidation to cone 6, But as a maker, I felt my work was far from over. As the clay reached leather hard it would be altered by adding layers of subsequent labor. The result is what I think of as visual interest. Whatever the process of altering or decoration one may choose, it seems important to me that it is there, furthering the visual impact of the piece. This does not seem like wasted time for me, it seems like the very reason to make something in the first place. For me, making pots is as much about a decorative surface as it is generating a form. Therefore, this idea of ornament coming after making, and it by definition being unnecessary, seemed very troubling indeed. This needed to be addressed where the trouble began in the first place, through the technical process of making. The system of making that I developed from this question starts with ornamental pieces, generated from press molds, that become both the skin of the work and its structure and form. Ornament is the primary building block in my work, integral and inseparable from the form. It provides a different answer to Trilling s challenge. What would remain if the ornament were removed from my work? Nothing, that is, at least from a more conceptual viewpoint. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 5

7 Decorative molds and examples of ornamental patties and strips. 2 A form mold can be used to make an open or closed form. 3 Clay pressed into a decorative mold. 4 Decorative pressings laid into the form mold. Intentional gaps are filled from behind to create depth. 5 A coil is pressed into the decorative mold providing an ornamental strip to coil build with. Molds The building blocks of my work are two different types of press molds, first a decorative mold that yields an ornamental patty or coil of clay to build from (1) and the other is a form mold, that can be pressed into to make the actual volume of the pots (2). This form mold is cast in a circular shape and, after clay is pressed into it, it is centered on the wheel and used to throw the upper portion of the jar. To make the decorative molds, clay is hand formed flat on the table, typically out of small elements such as coils or cones arranged in whatever shape I need. Cottle boards are set up around the object and plaster is poured in a simple, one-part-mold. The form molds begin as objects thrown on the wheel that are carved when leather hard, and typically cast in two-part molds. No pour spout is needed, as these molds are made for pressing, not slip casting. Clay After pressing clay into the decorative molds (3), I then set them into the form mold, ornament side down. I can vary the clarity of the ornament with the pressure I use to push them into the mold the harder I push the clay against the mold wall, the less ornament will remain. The composition of the pot s surface will depend on how the ornament is set in the mold (4). Once the form mold is filled, creating a half sphere, I trim the edge flush with the mold. This will be the bottom of my jar. A coil is pressed into a longer decorative mold (5) yielding an ornamental strip to build with. This is scored and slipped onto the press-molded base (6). This jar is made with two layers of ornamental strips, one on top of the other, making up the wall of the jar. The last strip is scored and slipped in place at a 45 angle, slanting inward (7), creating a nice shoulder to throw a flange for the lid to rest on. The jar is allowed to set up to a soft leather hard, just firm enough to support the pressure of adding and throwing a coil to make the flange. I center the jar (with the base still in the form mold) on the wheel and use a needle tool to cut the rim level. I score and slip a coil into place on the rim and throw a flange for the lid (8). This is one of the most dynamic parts of the finished jar; a strong horizontal line that conspicuously shows the different touch between the squishy, press-molded body and the precise thrown rim. I usually leave this rim unglazed as to increase focal attention. I throw the lid immediately after the rim so that they will both shrink at the same rate. I have noticed that even though the rim is freshly thrown, the body of the jar has already begun to shrink. This can throw off the precision of the lid fit. To compensate, I usually throw the lid slightly larger ( 1 8 of an inch or so) than the flange. When both the lid and the lip are leather hard, I trim the lid to fit the jar. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 6

8 Decorative pressed strips are added along the rim of the pressed form mold base to form the wall of the jar. 7 A top strip is angled to form the shoulder, then deep thumbprints alter the form and create another layer of pattern on the surface. 8 A coil is added to the shoulder and thrown to make the flange. 9 After the rim has set to leather hard, the piece is removed, turned over, centered on the wheel, and a coil is added onto the bottom and thrown into a foot ring. 10 A metal profile tool is used to make a clean and consistent knob on the lid. 11 The finished jar. Once the rim is leather hard, I remove the jar from the form mold and flip it over. Because the plaster form mold absorbs moisture, the bottom is usually a soft leather hard and ready for the thrown foot. I center the jar on the wheel upside down (resting on the rim), and mark with a needle tool where the foot-ring will go. This area is scored and slipped and a coil is added and thrown into a foot for the jar (9). Finally, after trimming the leather-hard lid to fit the jar, I throw the knob. I use a profile tool made from a piece of sheet metal to give me a precise, decorative finial (10). Additional profile tools are also used to make decorative marks on the inside of the lid and the bottom of the jar (11). I would like to end where I began, with insight provided by Trilling, If our speeded-up society leaves no time for labor-intensive pursuits, it is only because it has trained us to demand quick results. Using both hand-making and serial-production techniques (molds) connects me to the pre-modern, rich with lavish and wholly unnecessary ornament, while still allowing for the real-world concerns for efficiency. With this system, I can enjoy the hand labor and skilled making that I value, employ, techniques that quicken the pace of making, and maintain visual interest. the author A. Blair Clemo is a potter, ceramics technician, and wheelthrowing instructor at Grand Valley State University in Allendale, Michigan. For more information, visit This article originally appeared on pages in the December 2013 issue of Ceramics Monthly. Visit to subscribe. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 7

9 Softening Form with Color by Angelique Tassistro Imagine hours spent strategically glazing one platter with the perfect-checkered pattern. Then, imagine as one of the last dots is being applied, a giant blob drips from the paintbrush, splattering the perfect design. This happened to me. It was late, and I was completely exhausted! But the pressure of deadlines was ever present. At that point, it seemed the only thing left to do was to wash it all off and start fresh. And then, half way through cleaning off the platter and through the tears, I saw something quite lovely. It was less rigid, less defined, it was softer and sweeter. Since the incident as I now call it, my process has evolved organically. I create bold patterns and wash them away to discover something a little more subtle and understated, yet at the same time, with surprisingly more complexity and depth. My surfaces are created by layering five different underglazes, one on top of another. Two colors cover the entire piece and are then complimented by three accent colors. I use a mix of Amaco Velvet underglazes and Spectrum underglazes. Sometimes I mix the two brands together to get the unique color I m looking for. If this is your first attempt at layering color and working with underglazes, I suggest you make it easy on yourself and select five commercial colors that appeal to you. Choose your color palette the same way you would if decorating your living room. For example, choose a neutral base with a complementary/contrasting partner and then pick three accent colors that work well together but don t necessarily match. Be bold and have fun with your color choices. Allow your piece to dry completely after each step it s vitally essential to the process that you do this. Obviously, this can be a bit time consuming, but I recommend breaking the steps up according to what can be done day by day. This is a minimum three-day process. Prep Day Start with a clean, dry, bisque-fired piece make sure all dust and dirt are washed off and have been allowed to dry overnight. If the piece is even slightly wet, it won t absorb the color properly. Angelique Tassistro creates bold designs by washing away layers of underglaze to discover something a little more subtle and understated. Day One: Layer With a large mop brush, cover the entire piece with your base color (figure 1). It should be thick enough so you can t see through it to the bare clay. If the underglaze is really thick, water it down and go with two thin layers. Allow the first layer to dry before adding the second layer. Make sure all brush marks and drips are cleaned up with either a wet brush or a sponge before this layer completely dries. If the bisque piece is dry, it will absorb the glaze quickly, and you will be ready for the next step in about 10 minutes. Tip: If you start with the piece upside down, you can flip it over so it rests on its foot and you can finish the first layer without waiting. Next, wet the mop brush and apply the second layer of underglaze color (figure 2). While this second layer is still wet, carve a pattern into the surface. Think about a pattern ahead of time, making sure that you have space for three accent colors. While carving, use very little pressure so as not scratch or gouge the base layer. You re only carving through the second layer of color, revealing the base layer (figure 3). Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 8

10 1 Apply the first base color. Make this layer thick enough so you can t see through it. 2 Using a large mop brush, apply the second, top layer of color thick enough to cover the first layer. 3 While the underglaze is still wet, create a pattern. Let this layer completely dry. 4 Fill in one section of your pattern with the first of three accent underglaze colors. 5 Create large circles or other shapes with the second accent underglaze color. 6 While the second accent underglaze color is still wet, carve accentuating patterns. Work in smaller sections and more quickly if the top layer of color starts to dry. Tip: Use a banding wheel so that you can move your piece quickly without having to touch it. Again, pay attention to the thickness of the underglaze. If it is thick or seems slightly dry, wet your brush a little before you apply more color. (Some formulas are chalkier than others and tend to dry out quickly.) You might find it more helpful to cover the entire surface at once. This will give you a larger canvas for your pattern. Now, let everything dry just long enough so that the colors will not smudge or run together generally 30 minutes. Add Accent Colors Adding accent colors is one of my favorite parts because the possibilities are endless. One slight shift in color can change the feel of the entire piece. When adding accents, it s important to let each separate color dry completely before adding the next layer of color so that the colors don t blend. I can t stress this enough. For this particular pattern, I fill in the circles with a seagrasscolored underglaze (figure 4 ) and fill any open areas or larger spaces with big circles of hunter green underglaze (figure 5). Next, I go back with a wooden carving tool and add more carvings (figure 6 ). Lastly, I add small blue-green underglaze dots to all hatch marks (figure 7 ) or where the carved lines connect. Of course, this is not a rule, it s just what I do. Use it as a starting point to create your own unique pattern. Tip: The three accent colors stay more dominant if they are darker in color than the base and top layers. When you re finished, let the piece dry overnight. Try not to let it sit for more than 24 hours there is such a thing as too dry. If you let the underglaze become too dry, you will have to scrub it off and you will lose all of your color in the washing-off phase. Day Two: Organic Water Works Now comes the really fun part. The work done on day one will be washed away, but only part of it. Be sure to hold on to the piece tightly because once it s wet, it s slippery! Start on the bottom. Turn the faucet on so the water comes out in a light but steady drizzle and begin to rotate the piece Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 9

11 7 8 9 Apply areas of underglaze dots in a third color. Let the underglaze dry completely. Hold the piece under running water then lightly sponge the heavier areas. Allow excess water to run off. Let the piece dry completely, overnight if possible. 10 Buff the entire surface with a clean, dry rag. Remove any lumps or ripples. 11 Use a black underglaze pencil to highlight the remaining shapes and patterns. 12 Clean the rim with a damp sponge. Apply a dark, contrasting glaze with a small mop brush. under the stream of water. Don t let the water run on any single spot for too long and continue to slightly rotate the piece. Holding the piece upside down, scrub the bottom of the foot really well using a sponge. Then, gently, and using very little pressure, start removing some of the layers of underglaze, again using a sponge (figure 8). Warning: Do not allow glaze waste to go down the drain. Be sure to have a drain filter in place or similar system. If you start to see the clay, STOP! You don t want to remove all of the color. Lightly rub any thick lumps of underglaze with your finger until they dissolve. Stop when you re happy with the effect. When finished, hold the piece on its side so the excess water runs off (figure 9 ). Flip the platter over and repeat the same process. Creating Depth Once the piece is completely dry, gently rub the surface with a clean dry cloth to make sure there are no little bubbles left by the water, and to remove any remaining large underglaze lumps (figure 10). Using a black underglaze pencil, highlight the shapes to further accentuate the design (figure 11). The dark pencil line will make your designs pop and give the piece depth. If you re good with brushwork, feel free to use black underglaze and a fine tip brush. Next, cover the piece with a clear glaze. I use two thin layers of a clear transparent glaze covered by one layer of a translucent matte glaze. Allow the glaze to dry and fire it again. Recently, I have started adding carved ledges or rims to platters and other serving pieces and then applying a contrasting glaze onto the rim. I love the contrast of a black matte glazed rim opposite the wild, colorful, glossy pattern of the interior (figure 12). Finally, and most importantly, fill the platter with food and enjoy the feast. It s my goal to not only focus on the functionality of a piece, but also to create pieces that truly celebrate the relationship between food and art and that capture the essence of the feast in everyday life. By experimenting with this distinctive color process, I am able to create a piece with its own unique flavor. This article originally appeared on pages in the September/October 2013 issue of Pottery Making Illustrated. Visit to subscribe. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 10

12 Big Platters the Easy Way by Yoko Sekino-Bové Throwing large pieces (generally more than 10 pounds (4 kg)) is an exciting challenge for any potter; however, many people of smaller stature hesitate to muscle out big pieces. It feels like an emotional, as well as a physical, challenge. I felt the same way until learning how to produce large serving platters in an effective way at a tableware studio where I worked as an apprentice. Following their instructions, and some techniques from my own experience, I found that throwing large flatware, such as plates, platters, and shallow bowls, demands less physical strength and promises a higher success rate compared to making tall shapes because you don t have to lift a high wall of clay on the wheel. 4 Tips to Success To reduce the physical work and hassle, there are four things you can do when getting ready to throw a large platter. 1 Make sure that the clay you re using is soft. You don t need the clay to be firmer like you would for throwing a tall form, and it s less of a burden on your wrists while expanding the clay if it s soft. When using a fresh bag of commercially prepared clay that s too big to wedge, slam the bag on the floor a dozen times or so from different angles to condition the clay. 2 When you place the clay on the wheel, make sure to lay it on its side in relation to the spiral created from wedging. You will want to make the clay into more of a circular mound, but the illustration shows the orientation of the spiral. 3 The larger the plate, the greater the chance of an S crack appearing. Allow freshly wedged clay to rest for at least a few weeks before using it to create big platters. 4 Check the kiln s inside diameter. You can throw a plate or platter up to that exact size. As it dries, it shrinks and then fits inside. Throwing Process To make the wide platter shown here, I used 25 pounds of clay and a 24-inch-diameter bat. Place a bat on the wheel head then wet the surface. Place a circle cut out from a shower curtain on top of the wheel head. Make sure the curtain fits tightly and there are no trapped air bubbles. The shower curtain layer removes the need for using a wire tool to separate the platter from the bat, allowing the clay to release more easily when it s flipped over and ready to trim. Place the clay on the bat and start beating it down to a mound shape while slowly turning the wheel. Use dry hands (figure 1) or a wooden paddle (figure 2) and apply even pressure. Flatten the mound to create a cake shape about 3 inches high. If you want to have a high rim for a bowl shape, keep the mound about 4 5 inches high. The diameter of the cake shape will be the size of the foot ring of the piece (figure 3 ). Using a wet sponge and wet hands, open the form. Leave about 1 inch of clay between your fingers and the bat. Once the center hole is created, pull out toward you while also pressing down lightly with both hands to create a flat bottom (figure 4). While you expand and compress the bottom, move your hands from the center to the rim, then from the rim to the center several times. This throwing back motion can redistribute the clay and make it even (figure 5). It takes several passes to fully open up the form. Finally, use a rib to smooth and compress the flat surface. Once the bottom is open and compressed, start forming the wall. Pull up, compress the top, then move your fingers back down the vertical wall, compressing and essentially pulling down to keep it even. Keep the wall straight (figure 6 ). Leave enough clay on the rim, which will support the structure by tension. Using a very wet sponge, slowly open the rim (figure 7). When you flare the wall out, start from the rim and move your hands down the wall toward the center to keep the desired angle and prevent collapsing. When deciding on the final angle, factor in that the rim will move upward as it dries. The opening angle will be 10 to 20 degrees steeper when dry. Once the form is thrown, leave it uncovered for a day or two, depending on the humidity. In drier regions it may be necessary to cover the rim with a ring of plastic to keep it from drying too quickly. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 11

13 1 2 3 Place the ball of clay onto the bat and pound it down into a mound with your hands while the wheel spins. As the wheel spins, use a wooden paddle to further compress and flatten the mound until it s between 3 5 inches tall. Finish the process by pounding the clay with your hands again until you get to the diameter you want Wet your hands and hold a wet sponge in your dominant hand. Press down with both hands to open the form. Flatten ridges in the bottom by pressing down as you move your hands from the center to the edge and back again. Pull the wall straight up using your index finger on the inside and a sponge and knuckles on the outside. Compress the rim after the pull. Trimming To trim the platter, you ll need to flip it over. If it s a low, wide form, trying to lift it off of the bat directly and flip it would cause extreme distortion, so sandwiching the piece between two bats works better. Tip: You may need another person to help flip the big platter onto the second bat to prepare for trimming. It s better to ask someone to help you, rather than trying to do it alone and ruining the platter. Place a foam sheet on the center of the platter for support while flipping it over. The foam should be taller than your platter rim in order to support it. Cover it with a second bat that s larger than the diameter of the platter (figure 8). Use a flat surface to help with flipping. Create a pivot point by having one edge of the bat remain in contact with the table. Hold the bats together tightly to prevent slipping, lift one side up and flip the bat sandwich over as quickly as possible, maintaining contact with the pivot point to help steady the process and take off some of the weight (figure 9). This works better than trying to flip it in the air. Peel the shower curtain sheet off. Center the platter on the bat. Its own weight keeps it secured to the bat, so you don t need to place clay coils around the edge. Trim the outside of the foot ring first to define the platter s silhouette. The foot ring itself should be almost as wide as the rim, to allow for support. Sharp tools can reduce both the physical burden on your hands and the trimming time significantly. A center ring prevents potential sagging of the center part, so define that area, then trim away the excess clay between the two rings. The amount you trim away depends on the thickness of the bottom of your platter. For this platter, which started with a bottom thickness of 1 inch, I trim away about 2 3 of an inch of clay inside of each foot ring, leaving a bottom thickness of just over 1 3 of an inch. Make sure the inner ring(s) are not taller than the outer ring by checking with a straight edge (figure 10 and 11). For hanging, carve a deep groove into the outside of the foot ring (figure 12). This is less stressful to the foot ring than puncturing holes. After firing, use a loop of picture hanging wire placed in this groove to hang it. Flip the platter right-side-up using the sandwich method again and check the weight and appearance of the foot ring. Before the platter reaches the bone-dry stage, flip the platter occasionally to let it dry out evenly and to prevent warpage. Never pick up the platter by the rim; it may cause warpage or cracks (figure 13). Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 12

14 7 8 9 Use a very wet sponge, slowly open the rim. Angle the wall out, work from the rim down to the center. Place a foam sheet onto the center of the plate for support while flipping it over. Rest one edge of the bat on a table or your wheel head as a pivot point, hold the bats tightly and flip Trim the outside of the foot ring, mark the interior support ring, then trim away the clay between the two rings. Use a ruler or a level to check that the second foot ring is not taller than the outer ring To hang the platter on a wall, carve a deep groove into the outside of the foot ring so you can wrap picture hanging wire around the foot after it s fired. Carefully flip the plate back onto a clean, dry bat, and always transport it by carrying it as shown prior to firing to avoid warpage and cracking. Yoko Sekino-Bové is an artist and instructor living in Washington, Pennsylvania. To see more visit Firing tips n Always place a big platter in the center of the kiln for even heat distribution. The foot of the platter should be completely supported on a single, level, smooth shelf, otherwise, cracking and warping can occur. It may help to fire the platter on a thin layer of fine grog or on a waster slab made out of the same clay body to allow for lateral shrinkage during the firing. To prevent the rim from cooling off faster than the center part, which can lead to cracking as the rim contracts more quickly than the rest of the platter, evenly surround the rim with kiln posts. Alternately, when firing low, wide work, make sure there is adequate airspace between the rim of the platter and the shelf above it. Allowing air to flow freely helps to minimize the temperature difference between the middle of the shelf and the outer edge. n Do not place objects on the platter during a bisque firing. This can cause it to warp or crack. n Most of the center cracks happen during the cooling process. It will help big platters survive the thermal shock if you can slow down the kiln s cooling process, either by ensuring the kiln is fully loaded, or by adding a downfiring ramp schedule to the end. n Always use kiln wash and apply a thin layer of alumina hydrate solution to the unglazed foot ring. The weight sometimes makes a big platter stick to the kiln shelf during the glaze firing. This article originally appeared on pages of the May/June 2013 issue of Pottery Making Illustrated. To learn more about the magazine or to subscribe, visit Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 13

15 cone 6 glazes Paul Donnelly shares his cone 6 oxidation glaze and slip recipes. by Paul Donnelly. White glaze (altered from Val Cushing s 72 base) Cone 6 Dolomite % Gerstley Borate Whiting Nepheline Syenite EPK Kaolin Silica % Add: Tin Oxide % Zinc Oxide % Bates Clear Cone 6 Barium Carbonate % Gerstley Borate Whiting Minspar 200 Feldspar EPK Kaolin Silica % Add: Yellow: Mason Stain #6404 Vanadium 3.0 % Green: Mason Stain #6271 Mint % Blue: Mason Stain #6363 Sky Blue % All work is fired in oxidation to cone 5½ 6, generally around 2210 F. I always use a cone to determine when the glaze has matured. The Bates clear base can be very runny when fired in an electric kiln on a preset mode, which is typically 30 F hotter. 1 2 Paul s Clay body: Laguna WC-617 #16 Grolleg porcelain Cone 6 Tom Spleth Porcelain Casting Slip Cone 6 Custer Feldspar % OM4 Ball Clay Pyrotrol Grolleg Kaolin Opticast Kaolin Silica % Add: Water % Darvan % 3 1 Cup and saucer, wheel-thrown and handbuilt porcelain, White glaze, Bates yellow glaze, oxidation fired, Cup and saucer, wheel-thrown and handbuilt porcelain, White glaze, Bates green glaze, oxidation fired. 3 Platter, wheel-thrown porcelain, White glaze, Bates blue glaze, oxidation-fired, This article originally appeared on page 68 of the February 2014 issue of Ceramics Monthly. Visit to subscribe. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 14

16 Detailing the Surface: Incising and Resist Techniques by Doug Peltzman Tea Service for Eight, to approximately 12 in. (30 cm) in height, wheel-thrown porcelain, fired to cone 8 in oxidation. The teapot form has always been the most challenging and enjoyable pot for me to make. It gives the maker and user so many things to look at and interact with. The challenge essentially is to make all of the parts somehow work, both physically and aesthetically. The spout, handle, body, foot, lid, knob, and surface provide infinite possibilities for play. I ve happily struggled with those possibilities for almost ten years, and looking back, my teapot investigations have informed everything I ve made in clay. Surface Decoration My decorating technique requires incised lines inlaid with a black slip. When the teapot becomes leather hard, brush wax on the entire piece. Note: The added moisture from the wax can soften the piece, so be careful when handling. Once the wax dries, the piece is ready to be incised with lines, patterns, or drawings. I divide my piece into equal vertical sections using a ruler and a needle tool and incise horizontal lines by using the contours of the horizontal clay rings as a guide (figure 1). Now that the piece has been broken up into sections, I start by filling in every other square with a pattern. When all of the incisions are complete, begin to inlay black slip. Using a small brush, carefully paint slip into each line. You ll find that because of the wax layer on the clay, the slip beads right into the incision (figure 2). The wax also helps with the clean up. Use a lightly dampened sponge to remove any excess black slip. The wax creates a barrier and doesn t allow the sponge to remove clay or let the black slip muddy up the white porcelain. The last step in the greenware stage is to apply texture if Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 15

17 1 Separate the piece into sections by incising lines using a ruler and a needle tool. 2 Use a small brush to carefully inlay black slip into all the incised lines. Bisque fire the piece. 3 After firing, apply a layer of liquid latex to mask off specific areas for multiple glaze application. 4 Once the latex dries, apply the first coat of glaze. After it dries, wax those areas, then remove the latex. 5 Dip the teapot into the second glaze. The glaze will only adhere to areas where the latex had been removed. Wipe off excess glaze drips. Detail of Doug Peltzman s surface on his piece, Tea Service for Eight, after it is fired to cone 8. Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 16

18 Peltzman Base Glaze Cone 8 F-4 or Minspar Feldspar % Whiting EPK Kaolin Silica Zinc Oxide % Wintergreen: Add: Copper Carbonate % Alumina Wax Alumina part Wax parts Black Inlay Slip Peltzman Porcelain* in slip form cup Black Mason Stain # g *Substitute your clay body Peltzman Porcelain Cone 8 Grolleg % F-4 or Minspar Feldspar Silica Pyrax Veegum T... 2 Alumina % Top and above: Teapot, in. (22 cm) in height, wheel-thrown porcelain, fired to cone 8 in oxidation. desired. I use the teeth of a cut-up hacksaw blade to apply texture to all of the areas that aren t incised and inlaid. Finishing Bisque fire the teapot to at least cone 04, to ensure the clay body isn t too porous and doesn t absorb too much glaze, wash the piece to remove dust and allow it to fully dry. To mask off areas for applying multiple glazes, I use liquid latex. The latex is ammonia based, so use it in a well-ventilated area. Tip: To prolong the life of your brushes, designate a few to use with latex only. The latex is quite thick and fairly controllable to brush (figure 3). If you get some on the wrong area, wait for it to dry and peel it up. Once all the latex has dried, you can glaze the inside of the teapot. To glaze the outside, plug up the spout with a small piece of clay so glaze does not flood the inside of the teapot. Hold the teapot from the foot and submerge it into the bucket of glaze. Repeat the same steps for the lid, leaving the bottom edge where it will rest on the kiln shelf unglazed. Once the glaze has dried, apply a coat of wax over the glazed areas to ensure the second glaze coat doesn t adhere to or mix with the first. When the wax is dry, you can peel off the latex (figure 4). Apply a second coat of a different colored glaze (figure 5). The glaze will only stick to the areas where you removed the latex. Beads of glaze may stick to the waxed layer of glaze; just use a clean, lightly damp sponge to wipe off the excess prior to firing. When preparing to fire porcelain, apply alumina wax to the foot and lid so they do not stick to the shelf during the firing. Fire the piece to the recommended temperature for your clay and glaze. Doug Peltzman works as a full-time studio potter out of his home studio in the Hudson Valley area of New York. He is actively exhibiting and selling his work nationally. To see more of his work go to This article originally appeared on pgs of the July/August 2013 issue of Pottery Making Illustrated. For more information on the magazine and to subscribe, visit Copyright 2014, Ceramic Publications Company Clay Workshop Handbook 17