Citrus Reamer Mike Cerv

Appears in the Mar/Apr 2024 issue of Pottery Making Illustrated.

Throughout my artistic journey, I’ve explored ways to craft multiples. Like many, this began on the wheel and soon moved to slip casting in plaster molds. Eventually, I missed feeling the clay in my hands, so I looked toward bisque molds and slabs of clay. That process held my focus until ceramic artist Mike Helke exposed me to slab building with tar paper. During a visiting artist demonstration, Helke crafted a cube with ease using a T-shaped template adhered to the slab’s surface. Completely enamored by that potential, I began exploring how the tar paper technique could create more complex forms. Sewing patterns and steel-panel construction research spearheaded the development of my understanding of building shapes with flattened templates. 

Designing the Template

I employ digital modeling and output in the creation of my tar-paper templates to ensure perfect connections. I start by building a digital model of the desired shape—in this case, a reamer—with a 3D modeling software called Rhino 3D (A). It is important to construct the model using shapes that only bend in one direction (think cylinder, not sphere) because of the inelasticity of tar paper. Once finished, I then digitally unroll the model into flat components (B). If desired, I can also overlay a pattern onto the flattened vector. I export the file to a 5W hobby laser and cut at 78% power and 300 mm/m. 

Caution: Laser-cutting tar paper emits toxic fumes, so it’s vital to work only in a highly ventilated space. Never look at the laser while it is cutting. Even the light bouncing around the room is harmful to your eyes, and you won’t feel it. Always wear the correct filtering safety glasses when the laser is running to protect against permanent damage to your eyes. 

If you do not have access to 3D modeling software or a laser cutter, I sell pre-cut templates for creating functional objects online at mikecervpots.myshopify.com. 

Cutting Slabs 

Once your template is ready, begin wet work by preparing slabs to craft multiples of the same object in quick succession. First, flatten a block of clay to accommodate the shapes of the reamer template. Occasionally, lift the block to ensure it doesn’t get stuck to the workspace. 

Next, place a stack of ¼-inch (6-mm) wooden strips on each side of the block. Use a taut wire tool to glide along the thickness strips and slice through the clay (1). Remove a wooden strip from each side, reducing the height, and slice through the block again. Repeat this process to create a stack of nearly identical ¼-inch (6-mm)-thick slabs. Store the slabs in a damp box or wrapped in plastic. Tip: Yardsticks and paint stirrers work well as thickness strips for cutting slabs. 

Applying the Template 

Work on a flat, absorbent table or wareboard to prevent the slab from sticking, preferably a ½-inch (13-mm) cement board because it is smooth, durable, and absorbent. Use a metal rib to compress and flatten the surface of the clay. Lightly mist the slab with water and place the template on top. Then, roll a wooden brayer across the surface to fully adhere the template to the slab (2). If the template has cut-out designs, the tar paper needs to sink into the slab until flush with the surface to generate an even, low relief. With the template adhered, flip and compress the backside of the slab using a metal rib or paint guard. 

Next, with the template face up, cut against the template with a needle tool to remove the excess clay (3). Avoid beveling the cut inward where edges will be joined; an over-cut edge may not leave enough clay to score and join (4). Flip the cut slab with the template still attached over again and, with the template side down, slip and score all the joining edges. When in need of a more severe bevel, simply scrape the edge with a serrated rib at the desired angle. This method creates a small lip that, when a set of edges come together, acts as a pre-placed coil to smear (5). Repeat this process with the other templates for the reamer. 

Forming the Bowl and the Reamer 

Begin with the bowl section. Pick up the slab with both hands and gently bend it until the side edges can touch (6). Smooth and compress the interior of the seam with a metal rib to solidify the connection. Leave the template on the clay and firmly press the pieces together without marring the surface. 

Next, bend the spike section until its side edges come together. Join each of the six panels to their neighbors from the base to the tip, like a bud closing up (7). Note: On both parts, it’s important that the edges of the tar paper meet at their seam when joining. I’ve designed the templates to fit with one another at this diameter, so partially compressed seams could lead to the components not fitting correctly. Compress the exterior of the seams with a straight-edged tool (8), and the interior with a pointed silicone nib. Once all the spike’s seams are connected and compressed, peel away the template. Pull each panel from its tip before fully unrolling the template from the form (9). Press a wooden tool from the middle to the tip of each face to refine the spike from a hexagon to a hexagram. 

Connecting the Sections 

Slip and score around the base of the spike and on the bowl’s bottom rim, and then thread the spike into the bowl until the scored areas meet (10). Firmly pinch against the template and inside the spike to join the two components together (11). To strengthen the connection, add a small coil on the inside where the two pieces meet (12), pinching the coil into a triangular prism so it fits well in the crease. No slab is added to close the base; this allows multiple reamers to stack. Finally, peel the template from the outer ring (13). 

Gently sculpt the spout into a channel and set the piece aside to dry (14). Once firm leather hard, use a rounded tool, like a brush handle, to swipe against the outer seams of the spike. While not necessary, this action helps to ensure that the seams are well connected. 

Applying Decorative Slip (Optional) 

Once fully constructed, let the form firm up. To add a layer of interest beneath the glaze and brighten fired colors, coat the reamer with white slip. The drier the piece gets before applying the slip, the more drips that get frozen in place; alternatively, a wetter piece will allow the slip to fall down the form and level itself out. Wait until the piece fully dries and dunk it in skim-milk-consistency slip to get maximum variegation. Not all clay bodies can handle such dramatic rehydration without cracking or crumbling. So, before committing a completed piece to a slip bath, test how your clay body reacts to bone-dry application. Wait for the slip to dry entirely before checking for cracks. Many cracks will not be visible until fully dry. Now that the piece is slipped and dried, bisque fire the reamer to cone 06. 

Glazing in the Relief 

The crevices left from a pierced tar-paper template offer channels to fill with glaze. Use a small-nibbed squeeze bottle or an Airpen to squirt tin-opacified glaze into the recessed areas (15). With the same glaze base, colored only with chromium, spray a gradient around the piece. Be sure to leave some areas uncovered, as tin reacts aggressively with chromium to generate pinks and reds. Even a speck of chrome-colored glaze will modify the color of the tin glaze. 

Finally, dunk the entire piece into a thin, clear glaze, wipe the foot clean, and fire it to cone 6 (16). 

Mike Cerv earned a BFA in ceramics from the Kansas City Art Institute in 2017 and an MFA from Louisiana State University in 2021, before building a ceramics tool business with his partner, Griffin Gowdy. Cerv also works as an instructor and studio artist. To see his work and purchase tar-paper templates, visit him on Instagram at @mikecervpottery and online at mikecervpots.myshopify.com.