STRIKE FIRING: My Accidental Discovery in 1970
I began my ceramic arts journey at Rio Hondo Community College in 1968 with Martin Chodos. The emphasis was on wheel throwing and glazing, and Professor Chodos did the firings. In 1970 I transferred to Cal State Fullerton, where I began exploring the sculptural possibilities of clay.
Students at CSF took on responsibilities beyond making and glazing objects. For example, we were encouraged to fire our own work. At the beginning I made epic mistakes—under firing, over firing, and even blowing stuff up—but I was undeterred, eager to learn.
The biggest mistake changed the course of my ceramic studies, and eventually my career. It involved my first solo cone 5 glaze firing in a gas kiln. The kiln, an updraft, approximately 24 cubic feet, was fully loaded with plates and bowls in mostly glossy glazes (Cloud Blue) and decorated with overglaze engobes (P1) and copper. I was hoping for good results in the blue or green range.
I started the kiln in the afternoon, candled it overnight, and returned early in the morning to increase the gas. By midday the firing was nearly finished, around cone 4. There was only one problem: I needed to attend a lecture class and take a test. I opted to turn the kiln off early before I left. After about two hours into the class I realized that I had forgotten to close the damper. In a panic, I ran back to the kiln room and closed it, hoping that the firing wouldn’t be affected. I then decided to start the kiln again to try to get it to cone 5. But again back in class, I had a feeling that something wasn’t right… Oh darn (what I actually thought is unprintable), I hadn’t reopened the damper! I raced back and found the kiln in heavy reduction, ominously belching flame and smoke. Enough was enough. I shut the kiln off and headed home, convinced that all of my work was ruined.
The next morning I opened the kiln, steeling myself for the worst. Instead I was met with an unbelievable surprise. Plates and bowls dazzled with absolutely the most beautiful, spectacular colors and surfaces. All of the copper was red or metallic with huge copper-red fuming edges on the decorations. The glazes had red and pink blushes as well.
My mind was blown.
What had happened? My professors—Jerry Rothman, Jon Stokesbary and Vincent Suez—were awestruck as well. Of course they all asked me what had I done, and of course I said I didn’t have a clue. All I could do was recount my lapses in the firing fiasco. Jon Stokesbary had a thought. He described to me a process used in glass blowing called striking. Glass containing copper as a colorant is blown and transferred onto a punty rod. After the piece is cooled, it’s reheated in a heavily reducing gloryhole chamber, which will almost instantly flash or “strike,” turning the glass red and iridescent.
As it happened, my firing missteps paralleled this glassblowing technique. Relighting the kiln after cooling and putting it heavy reduction while the glazes were no longer molten allowed carbon to enter the still-porous glazes and react with copper only. Thus the glaze was unaffected and the copper was transformed.
I was excited to do another firing to see if I could duplicate the results from “the botched one.” This time there were no interruptions. As before, an overnight candle was followed by an oxidation firing to cone 5. No problems. I closed the damper and waited for the kiln to cool to a dull red heat (didn’t have a pyrometer in those days). The next step was guesswork. (Hey, it was all guesswork!) I relit the kiln and set the gas pressure at approximately two pounds, with the damper almost closed. The kiln began to reduce heavily, and smoke poured out of the spyholes. You could smell the carbon in the kiln room. The reduction continued for about forty minutes before I turned off the kiln. This time I closed the damper.
The kiln opening the next morning proved that the first firing was no fluke. Again, great results: pieces with colors I had never seen before in ceramics, colors that shimmered and bloomed. Over the years I have seen how these colors and iridescent surfaces have complemented the forms of my pieces.
At the time, I was sharing a studio with my classmate Kurt Schminke in the abandoned sculpture building at CSF. It was a huge space with an old red-brick car kiln formerly used as an investment burn-out kiln. In order to fire at higher temperatures, Kurt and I lined the inside of the kiln with a refractory castable cement. We fired in it almost every week for several years. Every glaze firing was a strike firing. Together, Kurt and I created hundreds of beautiful pieces. Eventually, we would jointly write a Master’s thesis on how firing manipulations influence engobe, clay, and glaze color. We referenced historical examples, both the Greek and Japanese methods. The main focus of our thesis, however, was striking, and we could find no mention of this technique in the literature. As far as we could tell, striking as post-fire reduction for cone 5 was born in 1970 at Cal State Fullerton.
From 1970 to the present, I have done countless strike firings. Each one has yielded different results, depending on the kiln, clay body, glaze, and firing variations. Choices are numerous. I fire between cone 3 and 6; should I fire lower or higher? Do I want a heavy strike, for intense results, or a mild one, for subtler outcomes? My preference determines the length of the strike or reduction. And at what temperature should I strike? My usual is around 1450-1550° F for 30 minutes. Also, not all glazes will strike. Glazes with boron strike well, and glazes that are alkaline do not. In a firing containing pieces with both glaze types, oxidation as well as reduction effects can occur.
Felix culpas—“happy faults,” or accidents that turn out well—have led to exciting developments in every field of human endeavor. Fleming did not intentionally grow the mold that would lead to penicillin. Columbus thought he would be landing in India. Every cook has a story about absent-mindedly using the wrong ingredient and inventing an exceptional dish. Mine is a small contribution to the long catalogue of felix culpas, but I am happy that it opened the door to exploration by other ceramic artists. For example, Vincent Suez has created gorgeous pieces using the striking method and taught it in his classes, as I have. Jun Kaneko, after visiting CSF in the 1970s, took it back to the East Coast and achieved impressive results in his own work. The phrase “unintended consequences” can have a negative ring these days, but for me, the consequences of my youthful blunder have only been positive.
Examples of my strike-fired work can be found in the collections of Scripps College, the Marer Collection, Cal Poly Pomona, and the American Museum of Ceramic Art.