Central Michigan University
Plan B Paper: Adapted from Independent Study Essay
October 20, 2004
Goals of this Independent Study in Ceramics (Summer-Fall, 2004)
Section I. Contemporary American Shino Glazes – A study of their origin, formulation, application, and methods of firing.
Section II. Kiln Construction – The design, construction, and firing of a 12 cu ft propane-fired cross-draft kiln.
Section III. Porcelain – The development of proficiency in the throwing and assembling of practical pottery forms in Cone 10 porcelain.
Section IV. Summary
Appendix B: Kiln Construction – August, 2004
Appendix C: Porcelain - September, 2004
Section I. Contemporary American Shino Glazes
In the 1976 issue of Creative Review, Michael Cardew stated: “Clay is a fatally difficult material. Paradoxically [it is] the most difficult material in the world to use because it’s the easiest. You can do anything and everything with it and it will not make any demands on you, a real handicap.” Certainly one of the most common materials in the world, clay, in one form or another, is available on every continent, and had been used by every civilization for making practical forms for the collection, processing, and serving of food as well as sculptural and decorative forms. Because of unique and readily available raw materials and fuels, their advanced and ritualistic society, plus the demand for everyday and special occasion utensils, potters in China and Japan have always attained a high level of sophistication in this craft. Always searching for products to please their customers, the development of the Shino-type glazes is inextricably bound to the use of tea, and to the celebration of tea, friendship, and hospitality thru the tea ceremony or Cha-No-Yu.
Written history can only give us a vague clue as to the origins of such a common plant as tea. Oral histories on the other hand, while sometimes subject to the enhancements of their retelling, are often far more reliable, and certainly more entertaining. Legend has it that there was a priest in India who had prayed without stopping for many years. One day, for no apparent reason, he simply fell asleep. When he awoke, he was so sorry to have broken prayer that he cut off his eyelids and threw them away, continuing his prayer non-stop for another five years without a single night of sleep. One day he again felt his body tempted by sleep, and took some leaves from a nearby shrub to keep his physical being occupied with chewing while his cognitive side continued with prayer. Witnessing these acts and soon learning of the benefits, people in the surrounding lands began to chew tealeaves and would eventually find other ways to use them as well. Throughout the history of the East, tea has been valued for its medicinal values; in addition to its ability to keep one physically alert and without fatigue, tea or Cha was said to uplift the soul and provide clarity of vision. By the Fourth or Fifth Century the use of tea as a favorite commonplace drink had spread across much of the Asian continent and eventually into Japan by the Seventh Century.
In the middle of the Eighth Century, a Chinese poet named Lu Wuh became the first to elevate the use of tea to a higher level and indeed his well-known writings encompassed every facet regarding the cultivation, selection, preparation, and presentation of tea. In ten elaborate chapters Lu Wuh described every exact detail and his work soon became widely acclaimed throughout the East (Okakura, 30). Though the mirroring of the harmony and order that he saw in his idealized view of nature and man, his ceremony of tea would differ in some ways from the later philosophies of Chado, as developed by the Japanese tea-master Rikyu, and which continue to be followed to this day. Simply stated, while the later Japanese development of Chado deals with the Zen concept of “greatness in the small (Koren, 50)”, formal tea ceremonies according to the works of Lu Wuh were elaborate, often gaudy affairs with strict formally patterned cups and other ware. Nevertheless to Lu Wuh is attributed the status as the first to create a philosophy, or an aesthetic, surrounding the use of tea (Okakura, 32).
Tea had been imported to Japan as leaf and powder as early as the Seventh Century. By the Eleventh or Twelfth Century enterprising Japanese farmers began cultivation of their own crops, and by the Fifteenth Century the use of tea in a ceremony that was roughly evolved from the ideals of Lu Wuh was in wide practice in Japan. Any evolution or change in philosophical attitudes may similarly be evidenced by changes in individual details. In this instance, it was the Japanese tea-master Murata Shuko (1453-1502) who was the first to substitute the use of the common, simple locally-made tea utensils in place of the formal, and often imported ceremonial tea ware that was in common use at the time (Tenaka, 32). While intended in part to support the Japanese sense of self-reliance, this change was an early signal of some deeper changes in the Japanese perception of beauty, which would culminate in the establishment of the social art of Wabi-Sabi several centuries later. The demand for these utensils, and the desire to satisfy the needs of the tea masters, would help promote development of more sophisticated pottery forms and glazes such as the Shino which was especially revered because of its warm soft feel and unpredictable surface effects.
Until Shino-type glazes came into use in Japan during the Momoyama period (1573-1615) there were no white glazes available in Japan. Ryõji Kuroda, in his book Shino, proposes that one possibility for the popularity of these glazes could be that they were inspired by a single white Chinese tea bowl owned by Shino Sõshin (1444-1523), who was an important tea master of his day (Kuroda, 5).
It is not my desire in this essay to paraphrase Ryõji Kuroda’s excellent resource Shino, for a more complete chronological understanding of the culture of this period, and the rising popularity of the Shino-type glazes, it is suggested that the reader consult that source. Suffice it to say that Japanese glazes of that era included a unique high-soda content feldspar glaze to which local potters added their “secret ingredient”, namely soda ash.
Conventional ceramic glazes consist of minerals suspended in water. When a conventional glaze is applied to pottery (for example by dipping it into a liquid glaze), the water first soaks into the clay body leaving these minerals attached to the outside of the pot. As the pot dries, the water travels back thru the glaze, and into the air, leaving the (now dry) glaze as a coating on the pot.
When soda ash is incorporated into a glaze formulation the process is somewhat different. Soda ash is different from other glaze components, it is soluble in water, and is actually absorbed into the clay body along with the water. When the pot dries, the soda ash is carried, by the water, to the outer surface of the glaze, and it is left behind on the outer-most surfaces when the liquid water evaporates. This outer-surface coating of soda ash, which melts in the kiln far before the rest of the glaze, is perhaps the main contributor to the interesting character of Shino-type glazes.
While Shino-type glazes (using a high-soda feldspar as the major flux) continued to be used in some places in Japan, glazes that used a high-potash feldspar as the major fluxing agent became more popular and were brought to Europe and North America during the early part of the Twentieth Century by Bernard Leach through his association with the Japanese potter Shoji Hamada. These glazes were to form the basis for practically all of the newly developed ceramics school, college, and craft curriculums that became proliferated in the U.S. and Europe during the period from the mid-1920’s right through to1970-1980.
While other areas of what most people would consider “high art”, such as painting and sculpture, had undergone a rather dramatic transition after 1900, through what we generally consider to be the early part of the Modern Period, pottery and ceramics had continued along the same, more or less, utilitarian pathways. Certainly, Bernard Leach and his disciples had affected the direction that the university-taught western pottery technique had taken from the late 1920’s on, but this would seem to be more in opposition to the industrialization of the pottery industry and the effects of modern society than following the trends of the rest of the western art world. In that respect Leach and his contemporaries could be seen as anti-modernists, for his influence was so strong during this period that the serious study of pottery seemed to have been unaffected by the modern movement in the way that painting and sculpture had been (Del Vecchio, 9). With the exception of the exceedingly sharp edged Scandinavian and German porcelain of this era, pottery and ceramic design more or less skipped right past modernism and continued with either the folk traditions of Europe or followed the influences of Leach and Hamada.
Unlike many other fields where it would be difficult for most observers to find a single significant date and event that would mark the beginning of any postmodern influences, Mark Del Vecchio, the author of Postmodern Ceramics, feels that there was a specific time and place for the beginning of a postmodern period of ceramics. That such a definite time and place could be found, would tend to indicate not how strong a force that postmodernism was, but instead it points out how strong the previous period was – in this case not modernism, but instead the traditionalism of the Leach/Hamada school. Del Vecchio would direct us to Robert Arneson, one of the leading potters of the 1960’s: “...he took a stand in 1961. While demonstrating throwing techniques at the California State Fair he threw a bottle shape, sturdy but inelegant, impressed the legend ‘No Deposit,’ and then sealed it with a hand-made bottle cap. At this moment the postmodern battle in ceramics had been enjoined (del Vecchio, 12).” But before the work of Arneson and a few other potters could be considered “Art” we have to understand that it was largely the effects of postmodern painters and sculptors who had laid the groundwork for this new freedom within the ceramics arena.
Around the same time that Bernard Leach was questioning the industrial roots of the modernist movement in pottery and began asking the first philosophical questions about the values of traditional pottery, painters and sculptors had began to look at their work differently. Artists in the past (and certainly there were some exceptions) had largely presented work within a historical context: “[they] ...set about representing the world the way it presented itself, painting people and landscapes and historical events just as they would present themselves to the eye (Danto, 7).” Arthur C. Danto in a series of 1995 lectures delivered at the National Gallery of Art in Washington, D.C. summarized the changes in the art world during the 20th Century that have brought us back to the a very basic question: “What is Art?”
In his fascinating analysis titled After The End of Art – Contemporary Art and The Pale of History Arthur Danto summarizes the crucial changes in the “high art” world that would lead the way to the broader acceptance of the innovative work of Arneson and the ceramists and potters who would follow him: “only when it became clear that anything could be art could there really be a discussion of the philosophy of art” “it was only in the 1960s that a serious philosophy of art became a possibility ...dispelling [the notion] that only painting and sculpture could become art.” “When a piece of work could ask the question ‘Why am I a work of Art?’ that signaled the end of Modernism (Danto, 14).” This was the question that was asked, not only by scholars such as Danto or del Vecchio, but most importantly by virtually every single “normal” person who was exposed to the Campbell’s soup cans and the Brillo Pad boxes of Andy Warhol, and opened the door for potters and ceramists to free themselves from the constraints of the label of “applied arts” to join the exclusive art world that had previously admitted only painters and sculptors. That this simultaneously put us all on the doorstep of postmodernism (in a larger sense) would almost seem to be beside the point to the traditional potter. As Harvey Shadow wrote in Ceramics Monthly not long ago “Art is Art – and everything else is everything else.” - if ever there had been a distinction between fine art and the applied arts it had come only from “the modernist’s need to categorize everything and to place a label on it (Shadow, 49).” Certainly ancient man placed little distinction on the materials– you either made something or you didn’t.
Curious, isn’t it? In some ways Modernism may have brought pottery in a full-circle. “Modernism came to an end when the dilemma...between works of art and mere real objects could no longer be articulated in visual terms, and when it became imperative to quit a materialist aesthetics in favor of an aesthetics of meaning (Danto, 77).” When artists could use whatever materials they wanted to, and could make virtually anything – and it was fully accepted as “art” – well, potters had found themselves at a very interesting crossroads full of potential.
And all of this brings us right to Virginia Wirt. Virginia was a student of ceramics professor Warren McKenzie at the University of Minnesota in 1974 and was working on her M.F.A. McKenzie challenged his graduate students to develop some glazes that looked like some of the lesser-well-known Japanese glazes, and Virginia began trying to emulate some white, often frothy appearing glazes. It was with her addition of larger and larger amounts of soda fluxes that these effects became more interesting, far more unpredictable and elusive, and this new type of glaze technique found a willing audience in (perhaps post-modern) potters, such as Chris Gustin at Alfred University, who were willing to gamble against odds for something unique, spontaneous, and perhaps even more aesthetically pleasing.
Chemically, Malcom Davis has described a Shino glaze as “an iron-loving brew, high in alumina, that is fluxed by alkalis.” Others have described a Shino glaze as “Fire on Halloween” and “Melting snow on a muddy road.” In practice, Shino glazes are mixed somewhat differently than normal suspension-type ceramic glazes. The soda ash is dissolved into boiling water and then added to the rest of the components and additional water. Unlike regular glazes where excess water can be decanted off the glaze a day later, the water used in a Shino cannot – for it includes the soluble soda ash. Shinos tend to be very temperature resistant; they stick well to the pots and seldom run. The migration of the soluble soda ash to the surface of the pot during drying lends itself to interesting surface treatments and decorations including wax resist painting, placing pots close together to restrict and to select those area of the pots where the soda ash collects, and other drying techniques such as covering the still-damp pots with fabric, stacking and nesting, or “plying” the flame of a propane torch across the glaze to promote faster drying in some areas.
In July of 2004, I attended a workshop by Malcom Davis, at Sierra Nevada College in Incline Village, Nevada. The specific type of Shino glaze that Malcom has been working with since 1989 are called “Carbon-Trap Shino”. This glaze uses typically larger amounts of soda ash (to 18%) and a kiln-firing procedure that restricts proper combustion of gas at the melting point of the soda ash (Cone 010 or approximately 1650F) on the surface of the pots, and allows large amounts of free carbon to bond with the melting soda ash. This procedure can produce some dramatic results, but good results are dependent on, and exaggerated, by all of the factors that normally affect any glaze result; namely thickness of application, thickness of the pots, humidity, wind, weather, personal karma, and the mood of the kiln gods, etc. When asked if some particular factor or another is more important, Davis answered: “It depends.” When asked if the clay body is important, he answered: “It depends.” He described his experiences, after fifteen years of experimentation, of using the same glaze formula, the same clay body, the same kiln, the same firing schedule, and obtaining radically different results from one firing to the next or even amongst similarly glazed pots placed next to each other in the same firing. Clearly, a good firing of a Carbon-Trap Shino “depends” on anything and everything. Fortunately, other Shino glazes are a little bit more forgiving. Nevertheless the unpredictability and unique characteristics of the entire family of Shino glazes have now found companions in both the aesthetics of the tea ceremony and an audience that can appreciate simple pottery as high art.
Since 1974 when Ginny Wirt mixed the first “American” Shino, many potters have been drawn to this elusive glaze family. Attached to this essay in Appendix A is a list of nearly sixty different Shino formulas that either Malcom Davis provided us with or I have collected. Davis’ admonition to us was that perhaps one of us, using this material, and the techniques and ideas that he demonstrated at the workshop, might just discover something new about or with a Shino-type glaze. In 2001, in Chicago, Illinois, Lester Richter organized the 1st Exhibition of American Shino and displayed the work of thirty-five potters. Interestingly Virginia Wirt left the world of clay not long after 1974, and is now a successful architect in Washington, D.C., but the results and legacy of her experiments have never been more evident.
Section II. Kiln Construction
After I returned from the workshop at Sierra Nevada College at the end of July, 2004, I began construction of a 12 cu ft propane-fired cross-draft kiln of my own design. Design sketches, construction photos, and the log from my first firing on October 1, 2004 are attached to this essay as Appendix B.
During the period 1974-1976 in Suttons Bay, Michigan, I was a studio pottery with my own shop known as Good Harbor Pottery. In 1976, Katy Bean and I married and we purchased some land near Kingsley, Michigan, built a house and barn. During the next 28 years, we raised two fine kids, raced sled dogs, drove horse carriages, made maple syrup, and persued several different careers. All the while the bricks and equipment from my old studio were stored in and around our barn. It was largely with these materials that I built this kiln.
It is smaller than the similarly designed kiln that I had in Suttons Bay, but the general principals are the same. Just as with the 1976 design, there will be changes that I will make to this kiln to make it fire more evenly and efficiently. While and electric kiln is predictable, a gas-fired kiln has its own personality, its own moods, and is highly unpredictable. Add to that the fact that, despite my overwhelming confidence, I’m relatively inexperienced at firing a gas kiln. As I write this essay, my first firing is in the last stages of cooling down and I’m sure that I’ll be seeing both success and failure in a few short hours.
In my second search for information about designing a kiln, I came to the realization that, even after more than twenty-five years, there still were no good books on kiln design. Neither Daniel Rhodes’ Kilns Design and Construction (while I bought in 1972), nor Frederick Olson’s 1995 book really provided good solid plans and information for matching a design with suitable burners, etc. As I finalized this design and looked for reliable sources on the internet, I realized that this project could become the basis for a book on kiln design. Most potters (at least those who would be building a kiln rather than buying one) simply want one design that fits their requirements, a material list, and a “how-to-do-it” that will save them time and money. Both of the aforementioned books are great on the historical development of kiln design around the world and are unquestionably good general resources, neither really helps the builder.
There are a couple of changes to make in the kiln. First, I should say that the burners have adequate capacity and I don’t need to change the orifice size at all. (if I can beg, borrow, or steal (or buy $750) an oxygen probe I could fine-tune everything, but even CMU doesn’t have an oxy-probe.
The bag wall needs to be opened up a bit, the top of the kiln fired hotter than the bottom. Remember, this kiln has both a recessed combustion chamber and a floor chimney flue. I have not seen this design in any book, but the idea is for a more consistent temperature. My old kiln design fired cooler at the top and had the burner inlets and the flue openings above the floor-line. I will be making adjustments for several firings I’m certain of that. Another note about this design: there is a port in the rear of the kiln that can be used for the introduction of either salt or soda should I ever decide to go that route.
Section III. Porcelain
During the first months of 2004, as the concept for this independent study was percolating in my head and I made my reservation at Sierra Nevada College, I bought a hundred pounds of porcelain. I’d never thrown porcelain before, not even 25 years ago. I’d always heard that it was so difficult to throw. I figured if I was going to Nevada, I’d better start learning. My first ball of clay on the wheel was practically erotic, if stoneware was clay, then porcelain was butter. I ran to the barn to get my wife: “Come back to the house and feel this stuff, it doesn’t even feel like clay.”
As the summer progressed and I prepared a group of pots for my first firing, my familiarity with this new material improved and I am pleased with the first 110 porcelain pieces that I produced during the month of September.
Section IV. Summary
Just about nothing is as humbling as pottery: handles shrink off drying pots, “s-cracks” on the bottoms of the best pots, glazes get mixed wrong, a million things can go wrong. You have to be pretty philosophical about all of this and not be too sentimental about each and every pot. You can always make more.
I was really happy with my throwing. I had a nice group of about 110 pieces (all bisqued) including a dozen teapots, 4-5 large (for me right now) covered jars, 3 dozen teabowls, and quite a few other interesting pieces. I especially liked the way my teabowl series had evolved – a low, wide thrown shape that was altered into a four-sided vessel. I had used two different types of lid construction for the teapot rims, and all of the teapots had integral pulled handles – most were looped over the top. All of my thrown pieces had evolved nicely since I had started throwing again in January.
So, I picked two Shino glazes to work with on this group: Malcom’s Carbon-Trap, and Dolly’s Russian Hotel. I had used both of these in Nevada. 6,000 grams (3 ½ gallons) of each were mixed, and I glazed about 75 of my pieces.
The kiln was loaded on Friday evening, the next day, and one burner was turned on at 9PM. It was windy, this type of burner has no safety or pilot, and it had been a lo(oo)ng time since I’d fired a gas kiln, so I watched the burners closely for quite a while. This kiln had not been fired before and the hard brick were old – even though August and Serptember were dry months and the kiln had been covered, I wanted to fire this pretty slowly. I went to bed at 3AM to catch a few hours of sleep. Up at 6AM, I checked my pyrometer (a brand new Fluke Model 52) and the top probe read 950F and the bottom 700F. I thought that was strange so I pulled a peep hole and looked in. I could see a kiln shelf at about 30 degrees from horizontal, so I shut down the kiln and went back to bed!
Up at 10AM and I pulled some upper bricks from the door to assist cooling, and to see if I could see what had happened. The kiln was loaded with 5 shelves. The middle shelf had totally cracked and separated. The upper two shelves had rotated about 20 degrees counterclockwise and were lightly wedged in place. The whole stack was pretty precariously balanced, but I was able to remove everything without it crashing. No pots were broken, just 3 teabowls had the glaze on their rims a bit scuffed up. Assuming that the broken shelf was just a chance occurrence, I decided the kiln gods were on my side and I reloaded the kiln and was back firing by 2PM.
The kiln fired well, I wanted to see how the temperature climb would be with minimal gas (and forcing of the process), and I kept a comprehensive kiln-log (in Appendix B). When Cone 10 was down I closed down the damper, restricted the primary air according to Malcom Davis’ firing schedule. Yes! Smoke! No problem getting smoke, and I was able to get a 118F degree increase during the one-hour heavy reduction period that followed. Proceeding with the remainder of the firing at a reasonable reduction level, in retrospect I could probably bump up the gas a bit and knock an hour or so off the firing time. Hard-brick kilns fire slower than soft-brick – but remember, I had these bricks.
At about noon, I had Cone 11 down on top and Cone 10 about ¾ down on the bottom. I figured that was good enough for this first firing and shut down the burners, plugged up the burners, and went to bed. It had been a long weekend so far.
The kiln was cool enough to unload at about noon on Tuesday (48 hours). Another shelf had broken but the stack was still standing (there had been no clue during this firing because this broken shelf was above the upper spy hole). Several other shelves were severely cracked. I learned later that silicon carbide shelves (these were ¾ thick) have a tendency to oxidize over time (mine were 30 years old) and that manufacturers had made significant advancements in shelf manufacture since 1974 due to NASA and the Challenger. Who else, besides me, in the whole world would have practically unused shelves this old? New shelves have been ordered from Larkin Furnace in Georgia – another $300 expense.
Glaze results were pretty inconsistent. I have no idea what happened to the “Davis-glazed” pots (which constituted about 60% of the total), but severe crawling existed on many of them. Davis’ glaze tends to be pretty ugly when there is no carbon-trapping, and the ones that crawled the worst were also the ones with the most carbon trapped. As Les Richter said: “Open the kiln after a Shino firing and understand why ceramics is an art not a science (Richter, 12).” The pots that were glazed with “Dolly’s” – either by itself or in combination with the Davis glaze were interesting. The best combination seemed to be with Malcom’s first, Dolly’s over the top and a wax resist in between. There were probably only two in the whole load that were glazed in that manner, but it was pretty obvious which they were. I had also tested some other non-Shino reduction glazes on teabowls:
Simply Red - Great promise, great red.
Melanie Brown’s Red #4 – Has some iron and looks like the reds didn’t develop as well.
Mary’s Blue (a CMU studio glaze from Dave Bolton) – great when over the top of Simply Red.
Hillux Green – a semi-matt dark green-brown that looks interesting.
Melanie Brown’s Tenmoku #4 – looked watery, glaze needs to be applied pretty thick for the dark glossy browns to develop.
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