Sculptural Vessels: Building with Slabs

Three Point Bowls, to 10 in. (25 cm) in diameter, soda-fired stoneware, glaze.

When making sculptural vessels, I impose a rule upon myself: every piece of the form should be able to stand alone as a sculpture itself. Visually breaking down my works, the whole form is composed of smaller forms, which influences my treatment of inflated walls, enclosed chambers, and volumetric components. These individual pieces come together to create a greater sculptural vessel, while also serving as a functional pot. Thinking in these terms guides the way I develop my current work.

I have always been curious about how objects are built, and I think about deconstructing three-dimensional forms into their two-dimensional blueprints. I understand forms by examining each plane individually and learning how it relates to the object as a whole, both structurally and aesthetically. For me, the most exciting part about creating a form is conceptualizing what shapes must come together, at what angle, in what order, with what supports, and where the center of gravity falls. While I consider these technical questions as I build, accompanying thoughts include aesthetic characteristics like composition, balance, volume, mass, symmetry, asymmetry, positive and negative space, planes, lines, shapes, and forms in relation to each other. These are all facets that make up my understanding of my language of shapes, which is my own personalized equation for what makes a form successful.

Reflection and Growth of Pots

Creating forms evolves naturally from my learned understanding of past forms’ physical and structural properties. I tend to think with my hands and sketch with slabs in the moment by holding them up in various orientations. The slab-by-slab, steady building tempo allows for constant reflection and consideration. In each making cycle, I build several similar pots in order to have a fast turnaround in experimental decisions because any kind of shift in form or function can create an entirely new piece. With slab construction, the slightest change in the size or angle of a slab will greatly affect the pot’s form; each slab directly informs the next, like a domino effect. Making a small alteration will not be obvious until the pot is entirely constructed. At that point, I learn what role a specific structural element holds, which then informs my construction processes going forward. This is how I experiment, learn, and find the best version of the pot.

Clam Vases, 9 in. (23 cm) in height, soda-fired stoneware, glaze.


Molds are a crucial tool in my process. I primarily use simple, bisque-fired, hemispheric molds that vary in diameter, height, and curve. I make the molds using thick slabs draped over a mother mold, a drop-bottom bucket, or a bowl. For the latter two techniques, I secure the bucket or bowl to the wheel head and, with the wheel spinning, press a rib downward on the slab until it reaches the desired depression. Once made, these are dried slowly then bisque fired. I prefer bisque molds because they are stackable and take up little space in my studio. Bisque molds retain and extract the right amount of moisture from the clay in a timeframe that aligns well with my work pace. The molds act as a movable working surface, supporting the curved slabs through various steps, and if made soundly, they do not chip easily. Sharp metal tools don’t mar bisque surfaces, so they do not wear down easily in comparison to plaster molds. My process uses both the convex and concave sides of a bisque mold to form and support a slab.

When preparing a slab with a drastic curve or bow, I form it while it is very plastic (1, 2), as it is easily altered, then gently dry it using a propane torch to reach the leather-hard stage faster while retaining its form. I use a large, shallow bisque mold as a torching surface because it safely contains the flame and residual heat while supporting the slab. We all know that clay has a great memory, especially when working with slabs. For this reason, I first use a bisque mold to forcefully imprint the initial curve and add elements like the foot (3–5), then I customize it with ribbing to fit specific parts on a form.

1 Stack the mold, slab, canvas, and bat, then flip them over onto the mold.

2 Compress the slab to the mold using a flexible red rib.

3 Make a coil foot, score the entire slab and foot with a serrated rib, then attach the foot ring.

4 With the bisque mold centered and secured to the wheel head and the wheel slowly spinning, use the side of your palm to begin forming the coil into a foot. Use a 12-teeth-per-inch serrated metal rib to gently move the clay around, compressing the coil into the slab and making a seamless joint. This rib acts like a trimming tool and works well with the wet clay.

5 Smooth the surface with a 24-teeth-per-inch metal rib, and finally a red rib to finish.

6 Flip the pot over after the foot and slab have dried to leather hard. Use an MKM Decorating Disk to divide the base into three parts with lines ascending from the outer edge, toward the center point. Divide the slab with guide marks surrounding the center point.


I enjoy working with templates and slabs. In the planning stage, they are almost interchangeable. I experiment with paper cutouts to visualize forms in a tangible sense and sketch in three dimensions, without having to commit to cutting and forming a slab (see 7, 13). Planning with paper helps when I apply a uniquely shaped slab that covers an area with a bend or twist I am unfamiliar with. I work with two kinds of material for templates: watercolor paper and heavyweight kraft paper. Because each vessel is different, my templates are always changing slightly. For this reason, I use watercolor-paper templates for shapes that I reuse, because the material is durable and designed to absorb and release water without compromising its integrity. I use the kraft paper for the special slabs that I may only need once, like the templates used for a slip-outline transfer method used to define the shape of an enclosing slab (see 17). Laying out and studying the many templates that create a pot helps me better understand the shapes I am interested in. I gain a two-dimensional understanding of how multiple forms come together, which again informs my language of shapes.

7 This first cut and alteration begins the illusion of movement that will be accentuated as the building progresses. Mimicking the curve of the cut and altered base, the bottoms of the templates are predetermined and cut to fit. These two templates/slabs define the way the rest of the pot will develop.

8 Use templates as guiding tools to assure a proper structural fit, then make reductive alterations to the slab, based on your vision for the pot.

9 Before attaching the next slab, make sure the first set of structural support slabs are your desired shape—each slab informs the next.

10 Plan the orientation of the next slab based on the shape and size of the first. Mark the area, score, and attach. The joining of these two slabs holds the cut-and-altered base in its new configuration. Because of the structural stress it is under, scoring, attaching, and compression are crucial in this stage.

11 Refine the vertical slabs that will be receiving the next slab. The plane that forms between these structural support slabs resembles the next slab. In making decisions to achieve compositional balance, always be aware of the invisible plane while building each pot. All six slabs meet exactly in the center, forming a foundation to support the next three slabs.

12 The illusion of movement in the undulating segments is determined by where the crests of the slabs lie in relation to each other.

Internal Supports and Markings

For me, a successful piece incorporates compositional balance, volume and mass, symmetry and asymmetry, and illusions of movement among the parts. The inside of my pots are complex, too. Internal structures, supports, and guiding or planning marks (6–12) are a large part of my building process and decision making when designing a form. Some structures are half hidden inside forms and extend outside as part of the form, while others remain entirely hidden, covered by the exterior slabs (13–19).

In the early stages of building, I draw guidelines that mark the center of a slab (see 6), which I then plan the rest of the pot around. This allows me to be constantly aware and keep track of symmetry and both aesthetic and physical balance as I build. My aesthetic inspiration is like the balance that the body seeks: if you stand on one leg and move around, your body will adjust its positioning to keep you upright with a safe, controlled balance. This concept reflects how I approach configuring my forms. I believe that what is naturally, physically balanced ends up achieving aesthetic balance.

13 Use paper templates to visualize the ideal curve of the slab, as well as to take proper measurements.

14 Use a hump mold to form a curved slab, then accentuate that curve with a red rib to fit the unique space within the pot.

15 Large openings allow for proper support and compression from multiple angles.

16 To prepare for the last set of slabs, rasp the area where they will be attached. This is a time of important compositional decision making, and using a reductive process, think about that plane, the lines, angles, and proportions it will contribute to the form as a whole.

17 Pierce holes in any enclosed spaces for air and moisture to escape. Next, create unique templates by wetting the edges of the slabs then press a piece of paper covering the area intended for the new slab. Pull the paper away to reveal an outline made of water and slip in the shape of the next slab.

18 Make the slab a bit larger to allow for error, keeping in mind that an altered slab being a three-dimensional object will fit differently than a piece of paper. Score, slip, and attach the final slabs.


As much as slab building can be a heavily additive process, for me, it is equally reductive. A lot of planning and consideration goes into the additive, or building components, while the reductive procedures require me to tune in differently—responding to, rather than guiding the pot. The work is already entirely constructed, with the finished form hidden beneath all the overhanging slabs and surface irregularities; it is now time to reveal it (20). This is a sort of meditative state in my process; instead of making drastic decisions, I remove small amounts of clay at a time to reach the desired curves, angles, and lines. This refining process involves using several tools that act as a series of coarse-to-fine grit implements, removing the clay with different intensities and techniques. In this order, I use a knife, rasp, fine-toothed serrated rib, sponge, and red rubber rib (21–23). Using these tools, it is possible to transform any slab to have a smooth, burnished surface.

19 Using a red rib and firm, even pressure, compress the seams.

20 Wrap the pot tightly in plastic to sit for at least 24 hours to allow the form to fully homogenize.

21 Begin the refining process by cutting away overhanging slabs.

22 Be careful to remove material slowly, and make minor shaping decisions with a rasp.

Firing and Glazing

In my finished pieces I aim to celebrate form, so my approach to glazing is subtle, allowing light and shadow to activate the surface. I currently soda fire to cone 10, and apply satin-matte glazes that take on subtle variation with the soda as it interacts with the architecture of the pot. Edges that contour the curves are accentuated and highlighted with carbon trapping and edge breaking. Because of the complex shapes and sizes of my pots, I primarily apply glaze by spraying. This allows for an even application where glaze will not pool or clog corners, as well as eliminates drip marks and fingerprints.

23 Use a serrated metal rib to refine the edges. Next, use a saturated, slightly rough finishing sponge to wear down the grooves, leaving a light layer of slip on the surface. Finally, use a red rib and the slip as a lubricant to compress and burnish the surface smooth. Allow the piece to slowly dry.

24 Three Point Bowls, to 10 in. (25 cm) in diameter, soda-fired stoneware, glaze.

the author Olivia Tani earned her BFA from the New York State College of Ceramics at Alfred University in 2017. Following graduation she moved to Minneapolis, Minnesota, as a 2017–2018 Fogelberg Studio Fellowship resident artist at the Northern Clay Center (NCC). Tani has continued her engagement in the Minnesota clay community and is currently a studio artist, gallery artist, and teaching artist at NCC. To learn more, visit or Instagram: @oliviatani.


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