Wallflower, 62 in. (1.6 m) in width, earthenware, glaze fired to cone 05, gold luster firing to cone 018. Photo by Peter Lee.
I am actually fortunate enough to own an entire set of Ursula Hargens dinnerware. In a stroke of genius (if I do say so myself), as my wedding was approaching, I let family and friends know about my love for Ursula’s pots and many were generous enough to give them as gifts. (Thanks everybody!)
When the “canvases” of her functional pottery became too limiting for her graceful painted surfaces, Ursula set out to expand her surface by creating large ceramic tiles – but not just your ordinary flat ones. Ursula constructs 3D canvases with negative spaces that add a whole new dimension to the hanging wall piece. Today, she explains her process. – Jennifer Harnetty, editor.
As the decoration on my thrown work has become more detailed and elaborate, I’ve begun looking to extend my decoration over larger surfaces. I chose wall tiles as a way to create large-scale compositions, treating the ceramic surface as a single canvas.
Fig.1 The MDF positive next to the finished plaster press mold.
In designing my tiles, I set out to create standardized units that could be configured in multiple ways. My goal was to make tiles that were manageable but could be combined to create larger compositions. Altering the shape of a traditional square tile by manipulating the silhouette allowed me to create patterns with the tile forms themselves. I could use the same molds to make different shaped surfaces, giving me the ability to modify the overall size or orientation of a piece.
In my Wallflower series, I use two tile molds to create arrangements that reflect different compositional approaches—a repeating pattern and a single decorative pattern that spans the surface of the tiles. The cutouts in the tile provide an added challenge, requiring the surface decoration to respond to the empty spaces, corners, and edges created by the irregular shapes.
Fig.2 Use a tarpaper template to cut a slab to fit into the mold.
Making the Template and Mold
To make the tile mold, begin by cutting a positive model out of medium density fiberboard (MDF) using a table saw and jigsaw. Sand the model to create a slight angle so you can remove it after the plaster sets up, and apply several coats of polyurethane to seal it. Make a tile press mold by setting up wooden cottles in a square, clamping them, and filling the seams with clay coils. The cottles should be at least one inch from the edges of the MDF model. Then, secure the model so it won’t move when the plaster is poured around it, coat it and the surrounding surfaces with Murphy’s Oil Soap, and pour in enough plaster to cover the mold by at least one inch. Once the plaster has set, remove the cottles, clean up the edges of the mold with a rasp, and dry it for several days (figure 1).
Fig.3 Add clay strips to form the sides of tile and attach them to the bottom slab with a reinforcing coil.
Pressing a Tile
To make a tile, roll a slab of clay ½-inch thick, and cut it in the shape of your tile. Use the MDF model as a guide or make a flexible template from cardboard or tarpaper (figure 2). Gently lay the slab into the mold and press the clay down, paying attention to the corners and edges as those are the areas often missed. Next, cut strips of clay to press into the sides of the mold and reinforce the seams with coils (figure 3). Cover the tile with plastic and leave it overnight so that it sets up to leather hard. The next day, place a board across the mold opening and flip it over as you would flip a cake, so that the tile rests on the board. You may need to tap the mold with your fist to make the tile pop out. Clean up any rough edges with a rib.
Fig.4 Apply a white slip with a soft, wide brush. Apply one or more coats as desired.
Applying Slip
Coat the tile with a first layer of slip (figure 4). A white slip produces a light ground and brightens glaze colors, but any slip color can be used. Pay special attention to the consistency of the slip and the wetness of the brush. If the slip is thin (like skim milk) and applied in quick, single strokes, it appears translucent in places with the red clay showing beneath. If the slip is thicker (like cream) and applied in multiple strokes, it creates an opaque, white surface. You can also affect the way the slip lays on the surface through the wetness of the brush; a wet brush gives you a lighter, more fluid application and a dry brush pulls on the surface leaving a denser, slightly textured slip layer. Allow the slip to dry until the sheen is gone and it becomes firm to the touch.
Fig.5 Apply colored slip over the clay and paper resist design working from the outside edge inward.
Using Paper Resist
Now apply any secondary slip designs using paper resist techniques. I make colored slips by adding 10–20% stain to a white slip base, but any commercial underglaze or slip will work. Draw an image or shape onto newspaper. If you’re going to repeat a design, make a master template out of heavier cardstock that you can trace if you need additional shapes. Use several pieces of newspaper so you’re cutting multiple sheets at once. With scissors or a matte knife, cut an outline of the pattern. Try to keep both the positive and negative image intact so that you have the option of using both the original shape and the outline in your design.
Fig.6 Apply additional layers of slip design on top of the first design layer.
Lay the paper cutout on the surface and spray with a light mist of water to adhere it. Try not to use too much water as it can cause the white slip ground to moisten and smudge. Using your fingers, press the edge of the paper to the surface so there are no buckles or gaps around the edge of the design for slip to seep underneath. After all excess water from spraying has evaporated, apply colored slip, brushing from the perimeter inward (figure 5). Once the paper has been tacked to the surface by the slip, you can go back over it to create lines or texture with your brush. Wait for the slip to lose its sheen, and use a pin tool to lift up the paper from the surface, revealing the resist pattern (figure 6). This process can be repeated multiple times to extend a pattern or create a layered surface.
Dry the tiles slowly between layers of sheetrock (drywall) boards and put something heavy (the press mold itself works fine) on top to prevent warping. I bisque my tiles to cone 03 in an electric kiln.
Fig.7 Poke holes through a design drawn on paper (laying on foam) to create a pouncing template.
Apply a Repeated Pattern
In order to repeat a glaze pattern multiple times, I use the Renaissance technique of pouncing. Trace the outline of the tile and pencil in a design for that tile shape. Then, perforate the paper by poking holes along the lines of the design with a pin tool (figure 7). This step is tedious, but once it’s made, your outline can be used over and over again. When finished, lay the paper on top of a bisqued tile and rub a charcoal stick over the holes. I’ve found I get a darker outline using a pouncing sack that I make by pouring powdered graphite (available at most art supply stores) onto a small, cloth circle that is gathered and tied off with a string or twist tie to create a small bag (figure 8). Pat the sack over the pin-pricked design to release the powder through the holes (figure 9).
Fig.8 Make a pouncing sack by pouring graphite into a cloth circle, then gather and tie it off.
Once the pattern is pounced on the tile, trace the outline with a pencil to connect the dots and secure the pattern since the tile is often heavily handled in the glazing process and the pounced pattern can be easily blown away.
Applying Glaze
The first step to glazing is outlining the pattern. I use a black glaze that I mix in small batches at a thicker than normal consistency. You can also let a glaze stand for a few days with its lid off to thicken it through evaporation. The glaze is then put into squeeze bottles with needle tips and applied as a drawn line. You can buy squeeze bottles at ceramic supply stores or make your own. I recommend using a 16 or 18 gauge nozzle.
Fig.9 Lay the paper template over the bisqued tile and pounce the design through the holes.
The glaze line produced from the applicator creates a raised line, making a little wall of glaze (figure 10). The second step in glazing is to fill in the walled-off areas with colored glazes (figure 11). The glazes for this step should be a cream-like consistency so they flow into the walled-in reservoir and create an evenly glazed surface. If the glaze accidentally extends outside the desired area, it can be scraped off with a pin tool or small knife when dry.
Once all the areas are filled in with glaze and the surface is dry to the touch, brush liquid wax resist over the glazed areas. This keeps the glazes true to their original color and texture after the next step and prevents the design from running and blurring. After applying the wax, allow the pieces to stand overnight so that the wax resist dries fully and there’s less clean-up.
Fig.10 Apply a glaze outline with a ball syringe, following the design pounced onto the tile.
The final glazing step is to dip, pour, or brush clear glaze over the surface (figure 12). This fills in background areas not covered by the colored glazes. I mix this glaze to a skim-milk consistency so it repels easily from the waxed areas. If it does cling to the waxed parts, remove it by dabbing with a damp sponge.
Fig.11 Fill in the outlines with colored glazes using a ball syringe or a brush.
Firing and Hanging
After glazing, fire to cone 05 in an electric kiln. I bisque higher than I glaze fire to minimize pinholing and other glaze defects. After this firing, I frequently apply gold luster in small areas and re-fire the tile to cone 018.
These wall tiles enable me to exploit the rich color, depth, and luminosity of slip and glaze while experimenting with pattern and imagery within a two-dimensional composition.
Fig.12 Pour clear glaze over the surface. Remove glaze from the waxed areas using a damp sponge.
| Editor’s Tip: Although Ursula uses a French cleat system to hang her multiple-tile installations, we suggest this system when hanging a single tile. Form two clay gussets to be used as hanging brackets. Attach them while the tile is in the mold. Score, slip, and then place them approximately a third of the way down from the top. Trim them to match the height of the walls. Pierce a hole in each gusset to later attach a hanging wire. This allows you to attach a wire and hang the tile after firing.
Photo and tip courtesy of David Gamble. |
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Ursula Hargens is a ceramist in Minneapolis, Minnesota. She received her MFA from the New York State College of Ceramics at Alfred University and studied ceramics at Nova Scotia College of Art & Design. To see more of her work, visit www.ursulahargens.com.
This article is featured in Pottery Making Illustrated magazine’s July/August 2011 issue.
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