Spotlight on: Guillermo Cuellar

Guillermo Cuillar bowl from his high fire reduction kilnGuillermo Cuillar bowl from his new soda/salt kiln

Photos: Guillermo Cuillar bowls from his high fire reduction kiln (left) and new soda/salt kiln (right)

GC: For me, salt glaze has an ancestral quality, which suits the kind of pots I make. Salt and soda glaze have become popular as a technique to finish very contemporary pots, but it is a traditional European process originating in the 14th century. It offered a convenient and cheap way of glazing a lot of pots. I like to give my pots a sense of age and use, so this reference to history appeals to me. I love the way people and pots interact at joyful occasions. 

In my high-fire reduction glazed stoneware I often rely on a crackle slip under my glazes to give them what I hope comes through as an “archeological” quality. But salt glazed pots fresh out of the kiln feel like they come with some mileage. The surfaces also evidence the unpredictability and accidents of the firing process in which the kiln can take some of the credit for any successes.

Bellarmine Jar, Collection of Warren MacKenzieWhen I came to the USA and visited Warren MacKenzie in the 1980s, I was blown away by his collection of old pots, such as his medieval German Bellarmine. I thought it was one of the most beautiful pots I had ever seen. (Photo at right: Bellarmine Jar, Collection of Warren MacKenzie).

KM: Have you worked with atmospheric kilns before or is this a totally new pursuit?

GC: I learned to salt fire at Cornell College in the early 1970s. It was the first kiln we built in school and I just fell in love with the surfaces produced. After years of making salt glaze pots (as well as glazed stoneware) in Venezuela, I am picking up where I left off 8 years ago, when I came to Minnesota.

Technical info

KM: Can you provide our readers with some quick technical information on soda and salt?

GC: Salt (sodium chloride) and soda ash (sodium carbonate or bicarbonate of soda) are all used as sources of sodium to combine with the silica in the clay or slip on the pot and form a glaze. They each have slightly different effects and can be introduced into the kiln in different ways. When you introduce soda ash or salt into a kiln it becomes vapor. It glazes everything — the clay, the posts, kilns, bricks, everything gets a sodium silicate surface. It is an aggressive material. 

KM: Can you clarify — are you using soda or salt? Or both?

GC: I mix 50/50 salt and soda ash, dissolve it in boiling water and spray it into the kiln. For simplicity I just call it “salt glaze”. When you introduce the salt, a cloud of smoke comes out of the chimney. With a recent focus on environment and safety, potters were led to believe this was toxic chlorine gas, but as I read more, I’ve learned that it’s apparently not particularly bad for the environment. Out of respect for the neighborhood, though, I mix the salt with soda and this reduces the noticeable white plume. 

KM: Yes, I have had older potters tell me about the healthy, mature trees they have witnessed growing over salt kilns. So, if you had to choose one or the other, do you prefer soda vs. salt, or is the mixture ideal?

GC: With only five firings under my belt with this new kiln, I don’t have enough information. I suspect that the soda is more localized in its effect and the salt more uniform. So I like the idea that the use of both encourages variations in the surfaces, but I don’t really know for sure. 

KM: You have a very supportive following for the types of glaze surfaces you currently produce. What do you perceive to be the advantages and challenges to changing that surface for your audience? Is your intent to stop making traditional glazed stoneware?

GC: I will continue to make my glazed stoneware, but you can’t really stay in the same place. I hope the salt firings will encourage evolution in all my work, while staying within the framework of pots for use. 

Salt Firing = Dessert 

KM: Is there something other than the surface that is important to you about salt firing?

GC: There is a social element about salt firing. Salt for me has always been a kind of dessert after the work of a glaze firing: it is fun and unpredictable and there are a lot of failures. My main body of work is glazed ware. But now I am enjoying the results of partially glazing the pots for salt and contrasting the two — salt and glaze. Salt has elements of accident and uncertainty — and that’s fun to share. I often invite potters to put some pieces in kilns.

KM: Do you envision your accidents and uncertainty influencing your glazed stoneware practice?

GC: I absolutely look to use the results of accidents and play-time with the soda firing to generate some change in my “regular” glaze ware. There is a great risk in being safe; once you have something that works, you have to have a certain amount of failure to have evolution. 

KM: You would like to take more risk with your forms?

GC: Yes, more risk with the glaze firing of stoneware pots. In all honesty, I am not a huge fan of the firing process. That is not the part that excites me. I am certainly most turned on by the mud and water parts — what happens on the wheel, while altering a pot … those surprises are really exciting. I agree with something John Reeve once said: he would never fire his pots if he didn’t have to realize them. I love the shiny wetness, so fluid and clay like. It doesn’t get much better than that! What is great about salt is that you put a slip on your pot and put it in the kiln. Ideally, the firing finalizes and enhances the piece. Glazing is so different. It fills in cracks, drips, adds color; it really impinges on the form.

KM: I want to go back to your comment about how fun it is for you to share this firing experience. Can you talk more about the role of sharing in clay? 

GC: You have an evolving relationship with any piece each time you use it. Each time you bring that baking dish out for a gathering, you add another layer of meaning to it. After a while, the piece is enriched by a “patina” of shared experiences. A casserole is only there to push you to go out and get some good, local, fresh produce and foods to cook in it. It gently pushes you to gather friends and be good to yourself. You are invited to participate with functional pots, and that participation inspires me to make pots for use.

KM: That makes sense. I know you as someone who shines when you gather people around pots, when you cook large batches of paella. It follows that part of what you enjoy most in this renewed chapter with soda and salt glazing: the social component of sharing the unexpected. 

GC: Yes — funny, when our pottery group had sales in Venezuela, they were called “Encuentro,” which translates to encounter, meeting, or gathering.