Using Red Earthenware Clay, Texture and White Slip to Create Depth

When a potter loses access to a soda kiln, her work takes an exciting turn as she figures out how to create depth on earthenware clay with texture and white slip.

earthenware clay

Kaitlyn Brennan was faced with a common conundrum of losing access to soda kiln firing after leaving school. With an old kiln that could only reach low firing temperatures, Kaitlyn made the switch to red earthenware clay and had to reinvent her work. It wasn’t easy at first, but after some experimentation, she discovered how she could create the exciting, rich surfaces she wanted using texture, white slip, and earthenware clay.

In today’s post, an excerpt from the Ceramics Monthly archive, Kaitlyn demonstrates how she creates her lovely surfaces. –Jennifer Poellot Harnetty, editor.

PS. To see Kaitlyn’s forming process and get her clear glaze recipe, check out the September 2018 issue of Ceramics Monthly!

Finding a Way with Earthenware Clay

I have always loved the surfaces that soda firing creates. As a student, I was entranced by its unpredictability and the fact that there was so much variation in how pieces could turn out based on their location in the kiln and how a kiln fired. After I left school, I didn’t have access to a soda kiln or even a gas kiln; however, I did have an old electric kiln. So my option was to switch to low-temperature electric firings. I really struggled with my surfaces. I had become so dependent on the soda kiln taking care of any variation and surface that without it, I was lost. I made some pretty ugly pots in trying to understand a new firing temperature, which also encompassed new glazes and slips, but through them I found my current approach to surface. I figured out that a white slip over textured red earthenware clay, especially when the slip was just the right thickness, allows the red clay to show through its surface. (Here’s a great low-fire white slip recipe to try!) It had the same depth and atmospheric feeling as my former soda-fired pots.

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Over time, several forms developed on which this textured red earthenware clay and white slip combination worked well. Unfortunately, I felt my thrown plates fell short. The surface felt shallow, as if throwing and trimming my plates removed all of the looseness I was trying to achieve. As soon as I tried making a plate from a slab, I found I could make it much more cohesive with what I was trying to do in my other forms.

1 Rolling craft-foam cutouts into a 3⁄8 -inch thick slab.

2 Dragging a texture tool dynamically across the slab.

My New Earthenware Clay Process

In my new process, I roll out a 3-pound slab of red earthenware clay to a thickness of about 3⁄8 inch, compressing both sides thoroughly with a rib. Then, I transfer it to a sheet of newsprint. Later in the process, the paper makes it easier to pick up my plate shape without distorting it.

While the clay is still fairly soft, I arrange flower and leaf templates cut out from craft foam across the slab. When I’m happy with their arrangement, I gently roll them into the clay (1).

3 Drawing designs into the clay using a pointed wooden tool.

4 Cutting out the plate shape using the rim of the two-part Masonite template as a guide.

The next step is adding texture. I use a tool that is designed for creating faux wood grain in paint. Texture is created by dragging the tool dynamically across the clay, creating waves and zigzags (2). Before I apply slip, I draw flowers and leafy vines into the clay using a pointed wooden tool (3).

When I started making these slab plates, I knew I wanted to dip them in slip just like my mugs, so that the slip would break over the clay texture in the same way. The challenge now was how to dip it in slip, but still be able to set the wet piece down to dry. The solution: brush wax resist (Check out this archive post for more ideas on using wax resist in the studio) on the foot of the leather-hard pot (4). When I use craft foam to scallop the foot it is easy to determine where to apply the wax because the foam creates a clear line to follow (5). Holding the plate with two fingers on either side, I dip it into a basin of white slip (6).

5 Brushing wax on the foot when the plate is leather hard.

6 Holding the plate with two fingers on either side, then dipping it into white slip.

**First published in 2018.

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