Crystalline Glaze on Porcelain: Signature Look of Pine Pottery

This month Handmade on the Front Range celebrates its first anniversary. In August of 2014, it launched with a four-part series on artisans who had participated in the Fort Collins Studio Tour earlier in the summer. The first of the series featured potter Susan Sternlieb, who showed me how she slumps ceramic bowls and platters. The last of the series featured Heather Bartmann and Cindy O’Neill, who introduced me to the potter’s wheel, along with Chris Wolff, a master of raku firing.

Crystal detail on pottery by Diana Begner

Diana Begner uses self-formulated crystalline glazes for a unique look on her Pine Pottery. This crystal is a small detail on a platter she displayed at Evergreen’s Summerfest.

Since last year’s studio tour, I’ve seen many displays of beautiful ceramics as I wander art festivals along the Front Range in search of intriguing handmade items and their creators. Always I’ve wondered what new information I might be able to share about the ceramic artists’ process. When I came to the Pine Pottery booth last month at Evergreen’s Summerfest, the possibilities became clear – crystal clear, I might say.

Crystals on porcelain or porcelain-like clay give Pine Pottery by Diana Begner its signature look. Glistening randomly on numerous pieces of functional ware, they reminded me of flowers or stars or ice on my window on a wintry morning.

How did Diana achieve that look? That was my first question — but that was just the beginning of what she would share with me at her studio two weeks later.

Crystalline glazes on functional ware by Diana Begner

Pottery of porcelain-like clay with crystalline glazes were on display at the Pine Pottery booth during Summerfest in Evergreen, Colorado.

Secrets of Crystalline Glazes

Ceramic glazes come glossy and matte, colored and clear, runny or not. It all depends on which of the earth’s elements they include, the temperature in the kiln during firing, and the amount of oxygen surrounding them as they respond to heat. Silica, the most abundant mineral in the earth’s crust, is part of the clay that potters work with and part of the glaze that finishes the clay. It accounts for the vitrification of both clay and glaze in the kiln; that means that both clay and glaze become like glass.

Ceramic urn with crystalline glaze by Diana Begner

A crystalline glaze high in silica and zinc oxide accounts for the unique surface of this urn by Diana Begner. (Photo provided by D. Begner)

In a crystalline glaze, the amount of silica is exceptional — so is the amount of zinc oxide. In a kiln fired hotter than 2000⁰F, silica and zinc oxide dissolve in molten glaze. Held in the kiln at a temperature where the glaze barely starts to solidify, they begin to interact, forming crystals. How long the kiln stays at that temperature determines in part how large the crystals can become.

Diana mixes her own crystalline glazes. Clear plastic boxes with labels like “copper oxide” and “cobalt carbonate” fill a tall cabinet in her garage. Her proprietary formulas, including firing times and temperatures, were born of persistence in the face of numerous failures.

No matter how Diana tweaks a formula, however, she never knows exactly what a piece will look like until she pulls it from the kiln. She can smooth all the rings that naturally occur on wheel-thrown pottery but might disrupt crystals; she can create the long or tall pieces of pottery that give crystals space to grow; but she can’t control where the crystals will form.

Shaping the Impossible

Miniature vases by Diana Begner

The tallest of Diana Begner’s miniature vases is shorter than American paper currency. The vase on the right was fired with her proprietary crystalline glaze.

Crystalline glazes weren’t all that caught my eye at the Pine Pottery booth. A large wooden display box showed off miniature vases, including the two pictured here. (A traditional glaze covers the smaller.) Note the size compared to our paper currency. Surely Diana couldn’t have thrown these on a wheel, I thought. I knew that a potter’s hands coax the clay into shape from the inside as well as the outside.

When I visited Diana at her studio in Evergreen, she smiled at my bafflement. She took a small piece of clay and set it in the middle of a small disk on her potter’s wheel. She sat down straddling the wheel and started it spinning.

Diana Begner throws a miniature vase

Diana Begner demonstrates how to throw a miniature vase on a potter’s wheel.

At first one finger did the job in the middle of the clay that several would do on a larger piece. As Diana pulled the clay up, the neck of the new vase became narrower. Eventually she removed her finger and replaced it with the handle of a fine artist’s brush. Two fingers continued to narrow the throat of the vase on the outside, while the brush handle shaped it on the inside.

When she had finished shaping it with special potter’s tools, she stopped the wheel and reached for a piece of thread. With the thread held taut between her hands, she pulled it between the base of the vase and the wheel. That was all it took to separate clay from the disk it sat on. Diana didn’t move the little vase, though. The clay is so malleable, all her creations dry on the wheel to prevent shaping mishaps.

Diana Begner pulls a handle for a mug

In her studio in Evergreen, Colorado, Diana Begner pulls a handle for a porcelain mug.

After she set the small disk with the vase on a shelf to dry, Diana grabbed another, larger chunk of porcelain clay. “Most people don’t pull their own handles [for mugs], and I think it’s because they’re told it’s hard,” she said. She held the clay high in one hand and pulled on it with the other. “They use an extruder instead. But those are hard to clean up. I own one — it’s lying in a corner somewhere.”

Diana moved one hand down the clay repeatedly while the other held it in air. Eventually a long section even in width and depth hung from the lump of clay in her hand. Diana broke it off and stuck it to the edge of a table where it would hang until it was dry enough to form into the curve of a handle.

Without a pause, she started pulling on the chunk of clay again and went through the process again. “I throw several mugs at a time,” she explained. “Then I pull the handles.” In minutes, four nearly identical handles hung from the table’s edge, and the only clean-up required was washing her hands. Diana had proved her point.

The Pine Pottery Business

Ceramic mug with digital image by Diana Begner

Monochromatic trees decorate this mug by Diana Begner. The trees were created by printing a digital image onto a material that completely fuses with the glaze during firing.

Diana keeps her eye on what customers seem to want. Although crystalline glazes are her specialty, she fires porcelain or porcelain-like clay with more traditional glazes as well.

Urns are common in the Pine Pottery collection.  Diana’s frustration in finding an acceptable urn for a beloved pet several years ago drove her to provide a variety for customers. She takes special orders and helps customers decide the size they need.

Diana has arranged to have silk fabric printed with enlarged digital images of crystals on her pottery. In 2016 she will introduce sleeveless silk tunics she makes herself from her own patterns. A stunning prototype in soft grays and white hung in her studio while I was there.

The Pine Pottery studio will be open to the public during the Open Door Studios tour put on by Evergreen artists, September 19-20. You can also see a selection of what Diana has available right now in her Etsy shop as well as past work on the Pine Pottery website.

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