The Chemistry of Art: an interview with Potter Ken Nagakui

I first met Ken Nagakui, an inconspicuous man, hunched over his notebook, pencil delicately but purposefully sketching shapes I could not make out.  As I studied this man’s concentration, I also noticed a plain clothed table in front him, bearing the weight of exquisite pottery I had not yet chanced to see.  The clay bodies were no smooth, sinuous shapes but rustic, with a mark of human imperfection.  They were a blend of ancient Japanese spirit combined with modern grit.  The following is a glimpse into the pottery business, a practice not so environmentally friendly by tradition, and a potter’s attempt to harmonize cost, aesthetics and environmental needs.

AGC: Hello Ken, can you please share how you became involved with clay pottery?

Ken: I had been painting for a long time before I started pottery –that was around 10 years ago.  I always liked pottery, but never thought I would make it a business until I saw the hand-built work of British potter, Jennifer Lee.  I was struck by the level of her work, its sophistication, technique and natural geological implications.  From there on, I took pottery classes in Alexandria, VA and, afterwards, moved to Nelson County.  Now I live and work in Charlottesville.

AGC: Through some research, I learned that it was not until around 3000 BC that the Mesopotamians began using a rudimentary version of the modern potter’s wheel.   Gradual improvements upon the turntable have sped up the process of coiling – or vertically layering coils to build the clay body – as well as have led to its mass production.   Can you describe your style and approach to pottery?

Ken: Hand-built and wood-fired stoneware is the shortest description of my work.  I do not use an electrically powered wheel, but roll pieces of clay to make coils and build the body.  In a way, this is very much traditional technique.  Next, I smoothen out the texture with my tools, some of which I fashion out of bamboo.  Stoneware, compared to earthenware, is vitrified to dense and hard rock-like quality.  Vitrification happens somewhere below or above 2,000 F, depending on contents of flux in the clay body.  When vitrified, the clay becomes dense or actual rock.  After it hardens, I add layers of glaze to the body and fire within my hand-built kiln.


AGC: How do you go about obtaining clay and glaze? Do you need to take safety precautions when mixing materials?


Ken: My first trial for this exploration was Virginian red clay.  By making slashes and screening impurities, such as stones and tree roots, the process to make clay from the soil is rather easy.  Since all clay shrinks about 12% to 14% from its original soft stage, I usually make clay pieces a bit larger than what the final product will be.   When fired at less than 2,000 F, red clay makes beautiful terracotta color pots.  I utilize this clay’s less plastic nature for the mugs to make crack-appearing surface and combine with better clay inside.


I tried several other local clays; some are from the Rivanna River, Blue Ridge Mountain, and a small creek in Harrisonburg and Lexington area.  Colors and textures range from purplish to somewhat greenish gray to deep brown to yellowish to white.  The most unusual one might be from the backyard vegetable garden where I currently live.  Its yellowish gray color means it is iron oxide, the most refined grain of clay.


So far, the only local ingredient for glaze has been wood ash from the wood stove, which uses varieties of wood, such as oak, maple, and hickory.  Although the main ingredients of glaze can be found in any soil, making glaze requires very fine particles and needs to be free from impurities.  It is practical to get most of glaze ingredients from suppliers.  Still, there are possibilities to try something new in glaze making.


One takes health precautions when mixing glaze because you start with a fine powder form of each chemical.  By using a dust mask, you can prevent or significantly reduce inhaling those particles.  I take environmental protection when discarding left-over glazes or when I wash tools and containers.  However, my usage of toxic oxides, such as cobalt and cadmium, is no more than regular painters’ usage of oils or watercolors.  Some substances are toxic by themselves, but when they melt into glaze, they become non-toxic.  For example, wood ash is considered toxic because of its strong caustic alkaline content, but when fired, it works as flux by lowering the melting point, and is no longer caustic in the glaze.


AGC: It seems that a certain amount of toxic minerals is utilized in pottery making.  There is currently a discourse over how to make pottery, as well as other industries, more environmentally friendly, but this is contested as unfeasible by some.  How do you go about building upon a craft rooted in tradition, while adapting to the realities of its harmful processes?  Would you ever say that pottery can be completely non-toxic?

Ken: When I first planned my own kiln, I wanted to utilize the woodland I happened to have, instead of using gas or electric power.  Where I live, it is easy to find dead tree branches to fuel the kiln.  Also, the kiln is based on a design called “fast fire wood kiln.”  This design allows me to fire within one day.  Comparably, traditional Japanese anagama kiln typically takes four to seven days to fire.  Of course, mine is a very small scale kiln and cannot fire large amount of pots.  What I am doing is a compromise between economically available methods, aesthetics and environmental concerns.


A friend and I have been discussing the possibility of a solar kiln.  My conclusion is it is possible, but not really practical.  If only a handful pieces will be used, then it is possible and can even be practical.  It’s very hard to imagine, however, that someone can build a solar kiln and fire 100 pieces at a time – unless “solar kiln” means, in fact, an electric kiln powered by solar panels.  I can imagine such kiln will be very expensive.


The U.S. Food and Drug Administration prohibits three elements in ceramic dinnerware: lead, barium and uranium.  Lead was widely used in ancient China, Persia and Japan because its toxicity was not known; lead is an effective flux at low temperatures but evaporates at high firing, so it is not even suited for my high firing technique.  I never use barium, though it is widely used for decorative purposes due to its brilliant blue pigment – it is, however, potentially very toxic.  If ever used for food ware, barium may easily leach into foods.  Some blue pigments contain cobalt, which can cause irritation.  Though it is mildly toxic, it is not prohibited by the FDA and is widely used.  I only use small amounts of cobalt, around 1% to 2%, because it is an effective colorant for lavender and solid blue.  Though I inevitably use some toxic metals, I make sure to seal them in the clay body by covering with clear glaze.

Ken’s pottery can be Found at Skylight Studios in Downtown Charlottesville.

Sarah Bolivar
Shenandoah National Park Trust Intern
Bachelor of Urban and Environmental Planning
University of Virginia  2011