Under Glazes May Co 1

ceramicarts dail y y.o r g

underglaze users guide

how to use underglazes, slip trailers, ceramic pens, and underglaze pencils This special report is brought to you with the support of Mayco Colors

www.ceramicartsdaily.org www.ceramicartsdaily .org | Copyright © 2010, 2010, Ceramic Publications Company | Underglaze Users Guide |

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Underglaze Users Guide How to Use Underglazes, Slip Trailers, Trailers, Ceramic Pens, and Underglaze Pencils Underglazes are basically clay-based materials materials with ceramic stains and metallic oxides added to create a ull spectrum o color in your work. They’re the astest, easiest, and most dependable way or you to add pizzazz to your pottery or sculptures or just an accent or an entire surace treatment. Like many other art materials, underglazes come in a wide variety o orms – liquid, dry, chalks, pens, and pencils – so no matter what your background, a ceramic surace awaits your colorul treatment.

Hunt Prothro: Using Underglazes and Stains on Porcelain by Susan Chappelear In addition to using bits o green beer bottles embedded embedded in his pieces, Hunt Prothro makes makes abundant use o underglazes and ceramic stains on his cone 10 porcelain to create a body o work that has roots in both ancient and modern cultures.

Laura Kukkee: Using Underglazes for Slip Trailing Trailing and Appliqué Techniques by Anderson Turner There is no shortage o application techniques using ceramic underglazes. Laura Kukkee creates her decoration with underglazes on newspaper then transers transers it to a reshly rolled clay slab. She also builds up layers o dierenct dierenct colored slips and underglaze decoration on newsprint to create a very thin slab. Then Then she cuts the slab into pieces and uses an appliqué technique technique to apply the decorated pieces to pots. She also demonstrates silk screened and inlaid appliqué.

9 Artists Using Colorful Underglazes by David Gamble With so many ways to use underglazes, it opens up so many opportunities. Just take a look at the eects Jim Kemp gets by spraying vivid colors on his teapots or how David Gamble expertly obtains a sketchbook eel with thinned out underglaze washes. Debra Fritts applies layers o underglazes and removes them to achieve her stunning patinas and Rimas VisGardas maximizes the underglaze’s ability to provide bold illustrations. These artists and fve more explore many possibilities you can delve into to add lie and vibrancy to your work.

Underglaze Pencils, Crayons, Pens, & Trailers Trailers by Robin Hopper You never have to limit yoursel to using underglazes out o a jar. Robin Hopper explores other underglaze options like ceramic pencils, wax underglaze crayons, underglaze pens, watercolors, and trailers. Whether you make your own or opt to buy, it’s just great to know you have so many options.


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Hunt Prothro Using Underglazes and Stains on Porcelain by Susan Chappelear

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hen Hunt Prothro speaks about his work there seems to be a clear rerain: clay as metaphor. Color becomes a powerul symbol relating to human states such as tranquility and restlessness. The thrown orm becomes subject matter, revealing emotional value as the gently swelling silhouettes suggest an abdomen, a navel. An expressive line encircles the curves and planes, leaving traces o a journey, journey, just as a skier leaves tracks in the resh snow. Ater obtaining a BA in Theology and Literature, Prothro was introduced to pottery during the seventies through study with Marguerite Wildenhain at Pond Farm in Sonoma County, Caliornia. Prothro attests that the legacy o those summer workshops is a continuing presence in his lie and in his work. Wildenhain was inuential in mid-century ceramics and is widely regarded or the integrity o cratsmanship applied to utilitarian vessels and or her unique approach to teaching. She apprenticed at the Bauhaus in Germany with Gerhard Marcks and, in Bauhaus tradition, sought to erase the distinction between artist and

Tahi vase, vase, 15 in. (38 cm) in height, thrown porcelain with undeglazes, stains, and gerstley borate wash, fred to cone 10.

cratsman that students may have accepted. Although Prothro rejects her absolutist teaching style, he describes her as having been personally enigmatic and he embraces her integration o lie and work. Seduced by early success in marketing thrown ware, Prothro continues to use a kick wheel to make a commodifed art orm. Using porcelain, he throws platters, bowls, and


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Platter, 20 in. (51cm) in diameter, porcelain with underglazes, stains, and gerstley borate wash, fred to cone 6.

cylinders in preparation or a cone 10 reduction fring with light reduction. He throws slowly and contemplatively, tively, developing voluptuous shapes, which will become canvases or studied surace articulation. Reerring to early Greek pottery, Prothro explained his preerence or vessels with thick rims and shapes echoing the human fgure. As a metaphor or the human longing or touch, his bowls invite handling. They are deceptively light, as the rims suggest a greater het. Tension is heightened urther by a subtle hesitation in the

rim. Additional declarations o resolution are accomplished by melted ragments o green beer bottles residing in depressions within the rim. Glassy run-o occasionally occurs, merging with other directional paths created by incising. Preacing the demonstration o his techniques o developing surace texture and coloration, Prothro reected on his travels in to southwestern France to study Paleolithic cave sites. His impressions were documented in “Notes rom the Paleolithic Project: Transience and Singularity,” present-


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Blue Dot Bowl , 14 in. (36 cm) in diameter, thrown porcelain with underglazes and stains, fred to cone 10.

ed at the National Council on Education or the Ceramic Arts (NCECA) conerence and again or the College Art Association in New York City. Prothro relishes the opportunity to consider the nature o human touch, the “pulse o the tool markings” and “the line that begins with authority but ends in ambiguity” as ancient metaphors. He eels that the poetic, lyrical cave paintings he studied helped to inspire a more complex line in his own work. Prothro oregrounds the linear percepts in his work, bringing history to

his pieces by appropriating ancient artistic techniques. With trimmed leather-hard bowls and jars o underglazes assembled on a classroom table, Prothro captured the audience as he proceeded to bring lie and proportionate harmony to the ware. Using a porcupine quill, he created surace tension rom linear movements over planes and curves, sometimes horizontally segmenting the cylinders into thirds with deep scarring. Defning planes with a canvas-wrapped paddle created subtle nuances o silhouette. Prothro


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Round vase, 10 in. (25 cm) in height, thrown porcelain with underglazes, stains, and gerstley borate wash, fred to cone 10, by Hunt Prothro.

says that the quality o line can become the content or “subject matter” o the vessel. We watched as a line bit, relaxed, and aded into a mass o cross-hatched etching. An edge o a shell was rolled across the surace occasionally to add variety to line quality. Reerring to the painter Paul Klee, Prothro moved rom a bold, expressive line to deliberate, constructive hatchwork produced by a wire brush. Other bowls and teapots on exhibit were decorated with deeply cut recesses. In these works, Prothro seems to be avoiding pattern, preerring to intuitively ollow the shape o the pot. Another bowl, glazed with neutral color over a more regular arrangement o marks, suggests equilibrium by the even dis-

tribution o linear elements. In contrast, the platters and vases provide more tension and movement as space in some areas is so compressed that the eye is induced to ollow an expressive directional line. When Prothro metaphorically speaks o the “bones o the piece” he is reerring to lie’s physical urges and the dynamic implications o a work o art. Cause and eect are revealed as his touch pushes back again. Apart rom connections we fnd to Paleolithic grid motis or color passages and intuitive line rom Abstract Expressionism, his sensuous vessels stir our eelings and we see orms whose parts are in a harmonious, balanced relationship with surace and structural qualities.


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Mixing It Up Although Prothro’s underglazes are poured on a palette, he achieves all o the color mixing on the bisqued pot itsel. He ollows a sequence to keep all suraces clean. He applies color to the oot, then the interior and, lastly, the exterior. The inside o the bowls are oten painted in counterpoint to the exterior; related, but distinct. He says, “The rim is a third area, a point o transition, and a zone o change with all the attendant hesitations and gestures o nality.” He applies broad strokes o black stain to all sgrattoed suraces, then gently wipes, leaving only the inlay to provide sharp contrast to the warm underglazes to ollow. Without any masking, he careully paints and dabs each piece to preserve a grid arrangement. In some o the pieces, gure and ground appear to be on the same plane, as hard-edged regions o color are juxtaposed to create contrasting tonal values and heighten each other’s vital nature. This interplay o shapes and colors, which have no representational associations, take on a painterly quality. In other pieces, he achieves coloration by scumbling layers o translucent washes, some o which he spritzes with water to promote color bleeding and to suggest distant galaxies. He preserves Top: Prothro brushes stains into incised textures beore careully wiping o the excess. Bottom: Complimentary colors are sponged on to enliven the surace.

the color eects with a thin, Gerstley borate-based clear glaze and strives to achieve a patina rather than a true glaze.


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Laura Kukkee Demonstrates How to Use Underglazes for Slip Trailing and Silk Screening Applique by Anderson Turner

Untitled, 23 in. (58 cm) in diameter, monoprinted (paint, slip trail, silk screen) slips on sot slabs, glazes, and sand then multifred.

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t is oten taught that artists must strive to be wholly original. We must envision something great and new and then apply it to our art, thus astounding all who happen by the work we’ve made. This is a tall order to say the least. Many a great idea has allen by the way side because the artist is unsure o how to execute the desired result. Oten, it is the subtle change in a technique that can lead to impressive results. One example o that type o change is in the work o artist Laura Kukkee. Laura, a native o Toronto, Canada, did her undergraduate studies with Bruce Cochrane at The Sheridan School o Crats and Design in Oakville, Ontario and developed

this technique in the crat studios at Harbour Front Centre in Toronto. Utilizing slips and underglazes in the decoration o clay has been happening or thousands o years. From the Ancient Greeks and Chinese to the 17th century country English potter, potter, the use o colored slip has been an important part o the decorative arsenal o nearly every clay artist. Laura is currently working with ideas surrounding the notion o a ragment. “This ragment is in the orm o an image or a pattern which is divorced rom its original meaning. By pulling ragments outside o their traditional contexts and restructuring the way in which they are presented, meanings become


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Slip Trailing Appliqué

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more elastic.” Her results in the research are both exciting and new, and they oer a chance or individuality that every artist strives or.

amount o Darvan #7 to get the “ow” o the slip she desires. It’s a good idea to test all slips and underglazes beore using them on your own work.

Notes on Slip

Slip Trailed Appliqué

Slip, as defned by Vince Pitelka in his book Clay: A Studio Handbook, Handbook , is clay suspended in water, usually the consistency o thick cream. It may be colored and used to decorate suraces, or may be cast into plaster molds to create ceramic orms. For her artwork, Laura uses slip the consistency o a thick cream as well as a slip that is substantially thinner. Note: Note: Commercial underglazes can also be easily substituted or the slips. She uses dierent proportions o water and a small

What you’ll need: ball syringe, newsprint, spray bottle, and plaster slab (optional). Laura sets the plaster on two pieces o wood to keep slab well ventilated, thus discouraging mold. You will also need the colored slips or underglazes o your choice. Wet a piece o newsprint using a spray bottle so that it is damp but not soaked. Smooth the paper out onto the plaster slab, so you don’t get ridges— smoothing helps the paper absorb wa1). ter (fgure (fgure 1).


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Remember, whatever color you use frst is going to be the outline o the pattern you’re making. You’re building color and pattern rom the top layer down with the background color applied last, which is the opposite direction one normally works. For this demo, I’m using black slip, though I have oten used other colors. It’s a good idea to mix and sieve slip thoroughly beorehand to blend all the materials. Dip the syringe in the slip and fll it (fgure (fgure 2). 2). To get the bulb owing, try practicing on an extra sheet o pa3). Slip per beore beginning (fgure (fgure 3). trail pattern or image o your choice onto paper. Pick the paper up by the edges careully and hold it up to light

so you can see your pattern better (fgure 4). 4). Set the paper aside and allow slip to dry until the sheen goes away, then start laying color in and around the pattern (fgure (fgure 5). 5). I like to apply bands o color together behind the pattern. Set aside the paper and let dry until sheen disappears (fgure (fgure 6). 6). Again, once sheen is gone, cover the colored slip with a white slip made o the same ingredients as your clay body, with roughly 3% Darvan #7 added to the mixture. Make sure the slip is really owing. Set aside and allow to dry until the sheen goes away or you’re ready to use. I oten apply up to our applications o white slip depending on how thick I


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Recipes

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want the slab to be. Usually though, one application is enough (fgure (fgure 7 ). ). Take the slip-trailed sheet and cover 8). with paper, then smooth (fgure ( fgure 8). Flip the slab over, keeping the new sheet o paper in place. Spray the paper with water until damp. Flatten the paper so that water spreads evenly 9). Begin peeling the corner o (fgure 9). the paper, being careul not to rip the clay sheet (fgure (fgure 10). 10). This will reveal the slip-trailed pattern (fgure ( fgure 11). 11). Take another piece o paper and place it over the pattern. Make sure to smooth it out, as this helps remove

moisture (fgure (fgure 12). 12). Flip the slab over and remove the paper (fgure (fgure 13). 13). Now you’re ready to cut shapes to apply to your pot, based upon your design (fgure (fgure 14). 14). Remove excess clay rom around the shapes (fgure (fgure 15). 15). Gently peel up one o your shapes. Brush slip onto the white side o the piece using the same white slip. Because o the Darvan #7, there is no need to score (fgure 16). 16). Gently press the piece onto the pot or sculpture you’ve made. The pot should be sot leather hard (fgure (fgure 17 ). ).

Sheridan Studio Colored Slip Cone 6-10 Grolleg Ka Kaolin         458% Kona Kona F4 Feld Feldsp spar ar      246 246 Pyrophyllite           8 82 Bentonite            51 Silica                163 1000% Plus 15% stain o your choice

Clay Body Cone 6 6 Tile Clay             50 lb EPK Kaolin            25 Kentucky Kentucky OM4 OM4 Ball Clay  25 G200 Feldspar          45 Ferro Frit 3124         10 Silica                 45 Whiting               4 Bentonite*            3 Plus 2 handuls o Epsom salts * soak bentonite overnight

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Inlaying Slip Appliqué

Inlaying Slip Appliqué Begin this process in exactly the same way as the slip trailing. Brush the slips in a design covering the paper. In this example Rahill is using a large pattern and bold colors. Set the paper aside to dry (fgure 1). 1). Once the gloss is gone, cover the design with the white slip made rom your clay

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body with approximately 3% Darvan #7 added to the mixture. Set aside (fgure ( fgure 2). 2). When the sheen has dissappeared rom the white slip, carve shapes in the slip. Be careul not to cut through the newspaper (fgure 3). 3). When you fnish the pattern you should be able to see light through the design.


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Cover entire sheet with black slip. Set aside to dry. When the gloss is gone, cover entire piece with white slip (fgure (fgure 4). 4). Smooth a sheet o newspaper over the slab, ip it over and careully remove the paper rom the pattern side, and spray with water, i necessary, to keep rom tearing the slab (fgure 5). 5). Place resh paper over the slab,

smooth, and ip the slab again. Peel the paper o the back o the slab. The slab can now be cut into shapes or appliqué (fgure (fgure 6). 6). Once the excess clay is removed rom between the shapes, begin to gently peel up the cut out patterns (fgure 7 ). ). Paint white slip onto the white side o each piece and gently apply 8). the shape to the pot (fgure ( fgure 8).


Silk-Screening Slip Appliqué

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Silk Screening Appliqué Items you need: squeegee, spatula, metal rib, small pitcher, brushes, a pointed tool, and various colored slips. Prepare paper the same way as in the previous examples ( fgure 1). 1). Position the silk screen on top o the prepared paper (fgure (fgure 2). 2). Pour a bead o black slip on the screen at one end only (fg( fgure 3). 3). Squeegee slip across the screen with steady, even pressure (fgure (fgure 4). 4). Use a metal rib to remove excess slip rom the silk screen (fgure 5). 5). Careully remove the paper rom the silk screen to avoid tearing the pattern

(fgure 6). 6). Ater the pattern is screened onto the paper, let it dry until the gloss is gone (fgure 7 ). ). Apply colored slip over the design and allow to dry (fgure ( fgure 8). 8). Ater the slip loses its sheen, cover the entire sheet with white slip and set aside to dry ( fgure 9). 9). Flip and add resh newspaper. newspaper. When this process is completed, begin to cut out the shapes (fgure 10) 10) Once the excess clay is removed, gently peel up the cut out shapes (fgure ( fgure 11). 11). Paint white slip onto the white side o the 12). shape and apply it to the pot ( fgure 12).


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Three completed orms with applied slip decoration.


9 Artists Using Colorful Underglazes by David L. Gamble

Teapots, Teapots, by Jim Kemp. Jim uses a low-fre red clay body and airbrushes underunderglazes onto the greenware. The last color he applies is black, which is sprayed across the piece to highlight the variations in heights o the surace decoration. The pieces are once fred to cone 02.

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ommercial underglazes are basically clay slips containing colorants, and they’re a great way to add color to your work using a variety o application methods. And since they’re ormulated to have low drying shrinkage, they can be applied to bone-dry greenware or to bisque-fred suraces. In addition to being able to change the surace color o your clay body, underglazes can also be used to change the texture o the body. When used to add color to suraces, underglazes have an advantage in that they are composed mostly o clay with very little ux, so they’ll

stay put and won’t run, which makes them ideal or detailed decoration. While most underglazes were originally ormulated or use at low-fre temperatures, most, maintain their color in the mid-range and some even as high as cone 9 or 10.

Simple Application Underglazes can be applied by brushing, pouring, dipping, and spraying—anything goes. Each application method has dierent requirements. I an underglaze is too thick or spraying or using as a wash, just add water to thin it down. I it’s too thin or silk screening or monoprinting, leave the container exposed to air to evaporate some o the liquid.


Underglazes work best with a clear overglaze, although other glazes o varying opacity and color may also be used. I’ve had success with whites and very light-colored glazes, but darker glazes seem to muddy or absorb the color o the underglaze. The overglaze can be anywhere rom matt to glossy. You’ll You’ll fnd the th e clear deepens deepen s the value o the colors regardless o application method. I you’re sealing the surace o work that will come in contact with ood, be sure to use a ood-sae clear glaze that matches your underglaze’s and clay body’s fring range. Applying an overglaze can be tricky. I you’ve applied underglazes on bisque, you’ll fnd that they’ll smear when brushing on a clear overglaze because wet glaze moistens the underglaze. Use a an brush and oat the frst coat on without going over the same area twice. Wait or the frst coat to dry completely beore brushing on a second coat. I’ve recently used underglazes to create a watercolor eect by thinning them down and painting them onto a semi-white glaze that is layered over another colored glaze underneath. The colored glaze (sometimes gloss, sometimes matt) melts through the white and gives it a richer o-white look. The clay body is a red terra cotta that can handle a number o multiple frings i needed. I’ve been creating pieces rom my travel sketches to permanently document places I’ve traveled to in a sketchbook-like manner. manner.

Testing the limits Through their testing, clay artists have been very inuential in the increased use and relabeling o under-

3 Women Praying, Praying, by Debra Fritts. Debra sculpts in terra cotta clay and bisque fres to cone 02. She then covers the piece with black stain and then underglazes are applied, wiped and scraped, then fred to cone 04. She continues with fnal additions and does a fnal fring at cone 05.

In this example rom my Sketch Book Travels, Travels, series, I bisque fred a clay slab to cone 03 then layered base glazes—3 coats o key lime with white, and 3 coats o low-fre white on top. The sketch is then executed with thinned out underglaze washes and fred to cone 04.


Rimas VisGirda slab builds his plate orms rom a terra cotta body. Following a pencil outline, he brushes on underglazes then applies wax to the entire surace. He redraws the gure and the outer border by scratching through the wax and into the clay surace and then inlays liquid black underglaze into the scratched lines. Ater bisque ring to cone 05, he waxes the gure portion and outer edge again but leaves the background alone. Ater sketching in fowers with w ith a pencil, he applies underglazes to the fowers, leaves, and stems and urther denes them with black underglaze. He applies wax over the fower stems and leaves then sponges blue underglaze onto the background. Ater ring to cone 5, he adds shading with an underglaze pencil then re to cone 3.

glazes. When they successully experimented with fring underglazes above the recommended cone 06 to a cone 5 with little or no change in color, manuacturers relabeled their products to reect the change. The hobby industry also helped promote higher ranges by developing a line o cone 5 casting porcelain, meaning more potters were working at higher temperatures. Even though the majority o underglazes can survive a cone 5 fring, usually resulting in a more vitreous surace, always test beore using them on your artwork. Through the years, my riends and I have done many tests, taking un-

derglazes to cone 10 in dierent atmospheres. Many o the underglazes change color and most become very vitreous, even glossy, without a clear glaze over top. I’ve even fred some underglazes at cone 11 and 12 with nice results. At the University o Indianapolis, Dee Schaad mixed some o the new bright red and yellow underglazes into a cone 10 clear glaze in a ratio o three parts clear to 1 part liquid underglaze. He then brushed the mixture on top o various cone 10 reduction glazes, including a tenmoku, with great results—the bright colors stayed bright. When potters told me


Paul Wandless Wandless paints und erglazes on plaster in reverse, painting the oreground rst and the background last. He then pours a low-re white slip on the plaster. plaster. This This picks up the underglaze image and inlays it into the clay. Ater bisque ring to cone 02, he applies a thin clear glaze then glaze res to cone 04.

Tom Meunick uses white stoneware or porce-

Steve Howell uses a body made rom hal porcelain and hal

lain then bisque r es to cone 06. He then uses

raku clay. Ater the initial bisque ring, he adds underglazes

underglaze pencils to draw on the surace. A-

and bisque res again. Because a higher bisque absorbs less

ter drawing, he atomizes it lightly with water

smoke, he bisque res cool colors to cone 06 and warm col-

then applies a glaze by dipping or spraying.

ors to cone 04. Ater the bisque, he places the piece upside down in a 2×4-oot brick pit lled with sawdust layered wit h copper carbonate, salt and bits o sticks and wood, then covered with a Kaowool blanket.


Ron Korczyski bisque res a white low-re clay to cone 04 then applies underglaze by brush on the bisque piece. He uses many underglaze colors in dierent size applicators that he can squirt out and draw line details and dots o color. The nal piece is red to cone 05.

that the new bright reds that fre to cone 10 blush out to white, it made me wonder i mixing them in a clear glaze would help protect them rom the salt when salt fring. Experimenting with all these colors allows you to fnd new and unexpected results when testing in, on, and under anything you have on the glaze shel. One thing to remember, however, is that i you’re using underglazes at a higher temperature than recommended, things can change. One clay artist using a black underglaze at cone 10 noticed that the next pint she opened looked the same in the jar but had a very greenish cast when fred. The company told her they had to reormulate because o government regulations and material availability and reormulated the color to ft their cone 06 to 5 suggested fring temperatures. The higher cone 10 temperature was overlooked and not taken into consideration.

Scott Rench silk screens images he creates on his computer. Images are screened onto the clay whil e it is still wet so it can later be shaped. Ater bisque ring to cone 04, Scott airbrushes a clear glaze and res again to cone 04.


Pencils, Crayons, Pens, & Trailers by Robin Hopper

F

or those who are excited about the graphic possibilities o the ceramic surace and enjoy using drawing implements that have something o a sharp, scratchy or linear nature, the marks made by pencils, pens, crayons and trailers likely will make them avorite tools o expression. These tools are the oundation o written or pictographic communication in Western civilization, whereas the brush is the oundation o mark making or most Eastern civilizations. Those raised in the Western traditions usually eel more afnity with scratchy drawing tools than with the sot, calligraphic brushes. Fortunately, the range o ceramic decoration tools encompasses both sot and hard possibilities.

Ceramic Pencils Regular pencils, with what we call “leads,” actually are made rom rom graphite o various degrees o hardness rom 6H (extremely hard) to 6B (extremely sot). Marks made with graphite pencils on ceramic suraces will burn out in the fring, which can be very

Trailers, ceramic pens, and pencils.

Jack Sures, Canada, Wide Bowl (detail), Bowl (detail), ceramic ink drawing on porcelain. Private collection. Photo: Judi Dyelle.

convenient, as the fring erases the guidelines or grids used or painting or drawing on patterns and designs in ceramic pigments. Guidelines also can be painted on with vermilion watercolor paint, which also burns away. Pencils or ceramic use (to make marks that don’t burn out in frings) are made with combinations o reractory materials, clays, and colorants and are usually only commercially available in one level o hardness that would probably equate to the HB rating o a graphite pencil. HB hardness is midway between 6H and 6B. Companies that produce ceramic pencils have a habit o coming and going, but most ceramic supply houses usually will be able to fnd and supply them. Pencils are commercially available in a very limited variety o colors. Ceramic pencils are normally used on bisque-fred clay that has been sufciently hardened to withstand the pressure needed or satisactory mark- making. Since the pencil “lead” may be quite ragile in use, the


Verne Funk, Caliornia, USA, Split—Portrait Split—Portrait of the Artist , 18 in. (46 cm) in diameter, wheel-thrown whiteware, underglaze pencil, glaze, 1996.

smoother the clay surace, the better the drawing. Bisque suraces can be smoothed by sanding with wet and dry silicon carbide or aluminum oxide papers, or the surace o the greenware may be sprayed or brushed with a terra sigillata coating prior to the bisque fring to provide a harder working surace. Ceramic pencils may be used on the ceramic surace just like their graphite equivalent on paper. Although sharpened points tend to wear quickly on the abrasive ceramic surace, the combination o pencil tip marks, side-o-pencil marks, and the opportunity to create tones through fnger-rubbing or smudging the sot image gives wide potential or drawn imagery development. I the commercial underglaze pencils are too sot or satisactory use, it is quite easy to make your own and harden them to a more satisactory and less riable state. Ceramic pencil drawings can be fred onto the bisque-fred clay to harden them

beore glazing, or, alternatively, they can be fred on unglazed high-fred clays, such as porcelain or stoneware, without the need or a glaze coating. The selection o colorants or mixtures o colorants used in the coloring o the “lead” will control the eectiveness o the drawings at high temperatures, but most will tolerate cone 10. To make ceramic pencils and pastels, use a porcelain-type slip with 50 percent white fring ball clay or plastic kaolin. For dry strength in the green state, 3 percent macaloid or 5 percent bentonite should be added.

Ceramic Pencil Slip Recipe White fring ba ball clay              50 % Potash eldspar                  25 Silica                          25 100 % Add: dd: Mac Maca aloid loid (or (or 5% 5% ben benttonit onite e)      3 Colorant (maximum)          15

% %

The materials, including colorants, should be dry sieved through an 80-mesh screen to ensure thorough


blending. For color, you can use mineral oxides, carbonates, and prepared stains. A variety o combinations will produce a wide range o colors, although it’s important to select colorants that won’t burn out at high temperatures; not many will, but cadmium/selenium and potassium dichromate are likely to do so. The amount o colorant can be up to 15 percent. More than that will cause loss o plasticity in the raw state, making it difcult to orm the pencils. The more colorant used, the more intense the color. Mix the dry materials with approximately 45 percent water, to which 1 percent o sodium silicate per 100 grams o dry material mix has been added. This will slightly deocculate the slip, giving additional green strength while also intensiying some o the colorants. Form the pencils by drying the colored slip to a plastic state, and then either rolling out coils or extruding lengths o the desired thickness. These then can be let as pencil lengths or cut into shorter 1–2 inch lengths. When dry, fre the pencils to between 1472°F (800°C) and 1742°F (950°C), depending on the desired hardness. A lower fring will produce soter “lead”; higher fring, harder “lead”. The short lengths can be placed in a claw grip drating pencil (the Koh-I-Noor No. 48 drating pencil can hold leads up to ¼ inch in diameter). Pastels normally are used rom the greenware state and are not prefred unless they prove too riable or convenient use. To make pastels, use the basic recipe above and simply

Lynda Katz, USA, Bayou Boogie Woogie, Woogie , 13 in. (33 cm) in height, thrown and aceted porcelain, underglaze pencil drawing with luster glazes, 1984.


Lynda Katz, USA, Covered Jar , 8 in. (20 cm) in height, thrown, altered, and hand-built porcelain, glaze-trailed decoration, 1997.

orm the clay into coils or extrusions to the desired size or use. I they prove too ragile, they can be fred to between 1112°F (600°C) and 1472°F (800°C) without making them excessively hard. Ceramic pastel drawings should be fred on the ceramic object to harden them beore a glaze is applied; otherwise, the powdery surace likely will be spoiled in glaze application or handling. Surace powder also might cause crawling through lack o glaze adhesion.

Crayons To make wax crayons, mix the dry recipe above with ordinary commercial wax resist. Form the crayon, and let it dry. Since the crayon will contain some latex, it also will have

a slight resist eect on the work, particularly when used on bisquefred ware. For a crayon with greater resist qualities, stir colorants into wax, let cool, roll the wax into rods o dierent widths, and cut the rods in convenient lengths.

Underglaze Pens Underglaze pens are like super-fne trailers containing an “ink” that gives good owability or drawing. They are available commercially rom a number o producers, or you can make your own with the fne trailers that are available. You can also dip any orm o “nibbed” pen, rom fne-pointed mapping pens, to quills or sharpened bamboo, into ceramic ink.


Black Ceramic Ink Recipe Calcium borate                  30 % Potash eldspar                  30 Ball clay                        25 Silica                          15 100 % Add: Bentonite                   5 Mason Stain 6600 or other black stain           10

% %

Thoroughly dry-mix these ingredients, then add a mixture o water and 5 percent sodium silicate (100 milliliters water to 5 grams sodium silicate). Pass it through a 100-mesh sieve twice. Thin the ink as appropriate or your use. This ink should work at all temperatures up to cone 12. It can be thinned to produce pen and wash-like drawings or used with a ceramic watercolor or glazes. Other colorants also can be used with this base.

Watercolors Ceramic Watercolor Recipe White fring ball cl clay              50 % Potash eldspar                  25 Silica                          25 100 % Add: Add: Maca acaloid loid (or (or 5% 5% be bento ntonite nite))      3 Colorant (maximum)          15

% %

For watercolors, the materials are mixed together, then enough water is added to make a slip, which is passed through an 80-mesh sieve and poured onto a plaster surace. When dry to the touch, watercolor cakes can be made by orming rounds or

squares o the colored slip and letting them dry completely. They then can be used like ordinary children’s watercolors by wetting the surace with water and applying with a brush.

Trailers A wide range o trailers or slip, ink, glaze or overglaze uses are available rom ceramic suppliers, kitchen stores, and drugstores. They usually consist o a rubber or neoprene bulb or container and a nozzle with a fneaperture tip, or sometimes multiple tips. The simplest to fnd is usually either a hair coloring applicator bottle or a child’s enema rubber bulb rom a drugstore. Ceramic suppliers oten have fne-tipped trailers, sometimes with interchangeable tips o diering aperture. The aperture o the tip required depends on the thickness o the material being squeezed through. Thin inks will go through a fne tip without clogging, but a wide tip may be needed or slips or glazes to ow properly. As with any tools, you’ll need to practice to get the correct “eel” to achieve the best results. Keep a thin needle tool nearby when working with trailers, because the fne ones tend to clog quite easily. n This article was excerpted rom Robin Hopper’s Making Marks published Marks published by The American Ceramic Society.



Under Glazes May Co 1

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