Smooth Lines

Just as clay has a strong physical memory, one of my most vivid early memories of using pottery was eating ice cream from a heavily grogged stoneware bowl at my grandmother’s house, back in the 1980s. Having managed a well-known Australian pottery studio and gallery from the late 1950s to the 1970s, my grandmother, a painter herself, had an extremely large collection of works from numerous accomplished potters. This didn’t mean much to the 8-year-old child who, rather than appreciating the beautifully thrown bowls with their finely tuned glaze, found the textural experience almost distressing. The spoon holding my creamy and smooth treat was drawn along the dense surface, giving a me a body shudder, like nails on a chalkboard.

As an adult the contrast of textures began to resonate, and in my more recent making years, I’ve embraced combining the smooth and rough. Being an artist who likes to experiment with media, pushing its boundaries and testing/learning as I go, I like to combine other (conflicting) clays, minerals, and rocks into my porcelain as well. And now, despite predominately working with polished porcelain, I have a huge appreciation for Mid-Century stoneware, and wait patiently for my mother to hand down those same dessert bowls that caused my distress 30 years ago.

After a decade of handbuilding with stoneware clays, I discovered how addictive working with porcelain could be. Frustrated with glazes and working left to right (the way I see traditional pottery processes), I began to experiment with nerikomi, the art of coloring clay and forming pattern blocks. With this process I work in reverse and feel like I have far more control of my work.

With qualities such as brilliant whiteness, translucency, and an exquisite smooth surface, these nerikomi slab-built dessert bowls were made with ice cream in mind.

Coloring Porcelain

The nerikomi pattern slices go all the way through the walls of the bowl, so they can be seen on the top through to the bottom. The nerikomi blocks are purposefully layered and complex, often inspired by my mood or the weather at the time. It was autumn in Australia when I made these demo bowls, the maple leaves had turned and kept blowing into my underground bunker studio, so I decided to work with yellow, pink, and orange stains and a deep brown for thin bordering lines.

To create the colored clays, cut 3 chunks of porcelain (100 grams each) and form them into small pinch pots. Add a small amount of stain to each pot. I work with about 8 grams of stain (1). You can weigh your stains and porcelain for an exact ratio. Each stain has its own strength and some colors don’t fire as high as cone 10, so I recommend testing in advance.

Add a few drops of water to each pinch pot to form a smooth paste with the stain. I use a simple wooden hook tool to scoop out the stains and mix/drag them through the porcelain into the stain as well, to prevent my fingers from drying out the clay. Continue to mix and blend the color into the porcelain until it’s all one solid color (2). The tone may appear dull; however, testing the colors you plan to use ahead of time will show you the fired color results. Once you’ve made your colored clay balls, store them in an air-tight plastic bag.

Next, I mix some colored porcelain slip. Always add water to your stain first to form a runny paste, then add your liquid slip (3). Adding powdered stain straight to slip won’t allow the stain to break down and you may discover small chunks of concentrated color later on. I use a small fan brush to mix the color thoroughly, then set it aside.

1 Add ceramic stains into small porcelain pinch pots.

2 Mix the colored stain into the porcelain until it’s fully integrated.

3 Add water to a ceramic stain to form a paste before mixing it into porcelain slip.

4 Paint a thin layer of colored slip over colored clay coils.

Forming Nerikomi Blocks

The Japanese name nerikomi translates from neri, meaning kneading, and komi, meaning into, which describes the process where pigments are mixed into wet clay, fusing the color completely through the clay rather than applying it onto the surface. Various colored clays are layered and compressed to form a solid block with a pattern working all through the inside. Patterns can be simple marbled effects to intricate images and designs. Images are revealed when the block is sliced in a cross section.

I don’t think I have ever created the same pattern twice. Some days, my patterns are well thought out and measured, on others, I like to take on more of an instinctual, haphazard approach.

Using a clean rolling pin and cotton fabric, roll out thin slabs of the colored porcelain. You can use rulers or thin boards of various depths to help create uniform thickness. Also, roll out long coils of colored porcelain, twisting coils of different colors around each other to create a marbled effect when sliced (see 4).

Using a fan brush and colored slip, coat the coils and some of the colored slabs to form thin layers of color. Select a contrasting color for this as they will become defining lines within the pattern (4, 5). Allow the slip to dry for about 10 minutes.

5 My workspace and the many elements that go into a nerikomi pattern block.

6 Piece together the various coils and slip layers to create a nerikomi block.

7 Try to avoid trapping air bubbles by pressing with your fingertips into the grooves.

8 When placing the layers, consider how the pattern will appear when sliced through.

For this pattern, I’ve used some plain white porcelain within the layers as well. Take turns layering the coils and colors, painting more slip between the layers (6–8). Next is my favorite part. I push all the layers together and give the nerikomi sandwich a good smack (9). The intricacy and precision of your pattern will determine how much shaping you’ll want to do. In my case, I like when the lines are stretched and distorted, so I purposely slap the nerikomi sandwich around and drag out its length (10). The overall length and width of the rectangular nerikomi sandwich reflects the size of the bowl or plate I want to make. I usually like to make the length longer than the diameter of my bowls as I prefer to have the pattern lines curved through on the diagonal. I wrap and store the pattern sandwich in plastic.

Next, I cut off a thick, square slab of porcelain that is the same thickness as the nerikomi sandwich. The length and width vary based on how much white porcelain clay I wish to have surrounding the nerikomi pattern. Using a cutting wire, I slice apart the slab of porcelain lengthwise on a diagonal curve based on where I want to position the patterned nerikomi sandwich. I place the nerikomi in between the cut edges of the porcelain slabs. To ensure the white porcelain and nerikomi pieces stick together well and form a cohesive block, I lightly mist some water on each side with a spray bottle. Press the pieces together firmly and pat the joined block’s edges into a rounded plate/bowl shape.

9 The layers coming together to create a nerikomi sandwich.

10 Shape the nerikomi sandwich by slapping, stretching, and compressing it.

Storing

I like to leave my assembled porcelain and nerikomi block to sit covered overnight to allow the moisture in the block to even out. If stored in an airtight bag, the combined block is fine to be left for a week. If left any longer, a light mist of water from time to time will keep it pliable.

Slicing and Forming

The fun part happens now as the combined thick block is cut into thin slices and the nerikomi pattern is revealed. I like to exploit the translucency of my porcelain, so I set my cutting harp on the first (lowest) level at approximately 1/8 inch (11, 12).

I drape each thin slice of clay over a plaster hump mold for these bowls, but they can be slumped into a form as well. Whichever way the piece is formed, the next step is essential as the porcelain needs firm pressure to reform its shape memory from a flat slab into a bowl.

On the potters wheel, use a sponge and a small amount of water to put pressure on the clay from the center to the rim (13). The small amount of water added blurs the nerikomi lines, but this will be trimmed and tidied up later.

11 Slice through the combined porcelain and nerikomi block with a tightly strung wire.

12 With the block sliced and separated, a clean pattern is revealed.

13 Shape the nerikomi slice over a plaster hump mold on the potters wheel.

14 Trim the bowl to the desired thickness, revealing the pattern again.

Trimming

Don’t leave the porcelain and nerikomi bowl on the plaster hump mold for too long as it can dry and crack as it shrinks. After a few hours it’s usually ready to trim with a metal kidney rib or loop tool. After trimming, the pattern is revealed once again (14).

If the bowl is ready to pop off without too much manipulation, its rim can be cleaned up with a sharp scalpel and smoothed with a makeup sponge (15).

For the first 24 hours, I dry my work on a studio shelf upright. After that, I have discovered that slowly drying the bowls upside down in a Styrofoam lidded box for 7 to 10 days guarantees the least number of casualties.

Firing

When completely dry, I bisque fire the bowls to 1832°F (1000°C) over 10 hours. The bisque-fired work is then wet sanded with 400-grit sandpaper, allowed to dry, and then fired to cone 10. I choose to not glaze my work as I prefer the polished surface, however, applying a clear glaze is also an option.

15 Once the bowl is firm enough to take off the hump mold, use a soft sponge to clean up the edges.

16 Polish each bowl and then coat with Liquid Quartz ceramic sealer to provide a stain-resistant and food-safe barrier.

Once high fired, I fine sand my bowls with 800-grit wet sandpaper. I apply Liquid Quartz (https://madeofaustralia.com/liquid-quartz) (16), which is a non-toxic, food safe, permeating sealer that turns unglazed ware into highly stain-resistant tableware. The bowls are now ready for ice cream.

All photos: Sabine Bannard.

Larissa Warren is a ceramic artist and art teacher living on Tamborine Mountain in Queensland, Australia. To see more of her work and hear about her workshops, visit www.ratbagstudios.com or Instagram: @ratbagstudios.

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