Icing the Clay — Ohr Not!

Editor’s note: this article was written by Bill and Pam Clark of Clark House Pottery. While quotes from this piece were included as part of the 2025 National Arts and Crafts Catalog article “A Balance of Reverence and Innovation: Arts & Crafts Style Glazes on Contemporary Pottery,” their full piece is featured below in honor of George Ohr’s recent birthday. 

 

 

Icing the Clay — Ohr Not!

by Bill and Pam Clark of ClarkHousePottery.com

 

When I refer to “Icing the Clay,” that is my term for the glazing found on the surface of pottery. When I say “Ohr Not” that refers to when George Ohr decided not to glaze some of his pottery near the end of his career. Glazing is all about chemistry to formulate a special surface creating a matte to shiny colorful result. The direct descendants of George Ohr, who are like a second family to us, have told us how George tried putting almost everything in his clay and glazes to try to achieve different effects. One unique one was putting horse saliva in his clay to make it more plastic.

We use the term “fire” when we cycle the pottery through the kiln going up to thousands of degrees in temperature for the glazes to melt onto the surface of the pots. This takes at least 24-48 hours each time. Each clay crafter/potter has learned to establish a style, surface coloring, and texture based on chemistry they have developed on their own. Most potters keep these special formulas private.

At Clark House Pottery, we have created a very diverse and colorful pallet by testing hundreds of specialty glazes. A finished glaze can be one simple formula like our F1 on a Skirt Vase (Fig.1). On the other hand to get the current Starry Night glaze (FIG.2) it has taken years of complex development. This glaze takes many hand-brushed coats of multiple types of glazes in a specific order. Each coat must also be completely dry before the next coat can be applied. We glaze with a brush to get into all the unique folds and ruffles. When our work results in a stunning glaze it is pretty wonderful. Some potters dip or use a spray gun to glaze. Some potters also take the time to use many colored underglazes and paint a whole scene and then fire the pot. Others have glazes that require special gases or oxygen reduced atmospheres inside the kiln to develop a color or surface treatment like Chinese reds and lusters. There are thousands of possible combinations of clay to glaze to firing techniques that make each piece of pottery extraordinary.

Mastering glazing technologies is also helpful when we are called upon to match/reverse engineer a glaze on an existing piece of pottery. A major auction house in Cincinnati contacted us in 2022 requesting our help. They had a client who managed to either break or lose a lid to a George Ohr teapot. They asked if we could make a close match, and we accepted the commission only if our studio name and mark were on the bottom of the new lid. After we received the teapot base, we first measured and made new lids. Clay constantly shrinks from the time a piece is made from wet clay through to the finished glazed piece. After making the lids, we evaluated what we thought might be a range of glaze possibilities for a close color match and surface finish. With that information we made a series of glazing test tiles and fired them. This process also had to take into consideration what colorants, such as iron, might be in the clay itself, which will affect the outcome of glaze color and texture. The picture above is one of two sets of glaze test tiles we created.  The best matching glaze ended up being a mix of iron and copper-based glazes on red earthenware clay. It is the tile second from the left on the front row. We did have some fun envisioning what the next teapot lid design might have looked like, you’ll see that picture below (FIG #4). The final lid chosen was the simple flat one with the small little knob. This commission was covered in an article published in The Journal of the American Art Pottery Association (AAPA) in the Spring 2023 VOL 39, No. 2 issue.

When you visit the contemporary craft firms at the National Arts and Crafts show, we hope some of this information might give you a better understanding of some of what is required in our craft. Some might be trying to match current or older decorating color trends. In all cases, everyone is trying to produce the best art pottery treasure for you to take home.

 

Visit ClarkHousePottery.com to see the works of Bill and Pam Clark.

 

 

 

You can visit Bill and Pam Clark online via their new website HERE. 

.