Low-firing and Burnishing
Because low-firing is the most basic of all ceramic techniques, it treats all your senses. Using just about the lowest possible technical setting, you submit your work to flames and smoke giving you a sense of what the ancients felt when they used fire to create their primitive works. Both ancient cultures and contemporary potters have used low-firing to great effect, adding slips and burnishing pieces to create finishes not possible with any other firing method...(Scroll for more.)
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Softcover | 112 Pages
Order code B066 | ISBN 978-1-57498-293-0
…Potters who burnish are often asked ‘what glaze is that?’ by curious admirers of their work. Non-potters naturally assume that all pottery is glazed, and the glossy surface of a burnished pot seems like a different and intriguing sort of glaze. Though glazed pottery can be brighter and more colorful, a burnished pot has a glow from within and a warmth that glazed pottery doesn’t have. The difference that non-potters sense without knowing it — and which fascinates potters — is that the surface of a burnished pot doesn’t wear a coat hiding the clay itself from view. Glaze is glossy and reflective, but the reflecting surface consists of a millimeter or so of glass covering the clay. Underneath this layer of glaze the rough stony clay is always perceptible, even if not always visible.
A sensuous surface
A burnished pot can have a surface just as glossy and reflective as any glaze, but behind this glorious surface there is no hidden roughness. Even the feel of a burnished pot is seductive. While a glazed pot feels hard and cold, a burnished pot seems warm and almost soft to touch. Potters who burnish get used to seeing people handle the pots, turning them in their hands and stroking the surface. This is a common and unconscious response to the sensuousness of burnished pottery.
Burnished pottery in history
The archaeological remains of many civilizations bear a resemblance – ancient pottery from China or the Mediterranean region almost seems more closely related in form and decoration to native African or Native American pottery, than to modern pottery from those regions. Now that modern pottery has come full circle to rediscover the beauty of burnished pottery, the history of unglazed pottery around the world is of interest to the modern ceramic artist. You’ll find the history of low-fired work from China, the Mediterranean, Africa and North and South America both informative and inspirational.
There are two methods of burnishing a pot: rubbing the clay with a polished stone or other smooth object, and coating the pot with terra sigillata and rubbing it with a soft material such as a chamois leather. While using a stone is more time consuming and takes a lot of practice, it can produce a high degree of sheen. Discover how this technique is done by the traditional style of the potters of the American Southwest and also at burnishing stoneware/high-fire clay, burnishing a high-talc earthenware clay, burnishing leather-hard or black-hard clay, burnishing on the wheel, burnishing tools, types of clay to use.
Burnishing with terra sigillata
Terra sigillata means ‘sealed earth’ and comes from the name of a type of Roman pottery mass-produced around the first century AD. But the Romans copied the Greek technique used in their famous black and red pottery for hundreds of years before that. Here is a complete guide to making and applying terra sigillata, recipes, and troubleshooting.
Smoke-firing and black-firing
Essentially, to turn pots black all you need to do is to smother the fire when it’s hot, and prevent oxygen from touching the pots before they have cooled. This process can take place in a kiln, in an oil drum or metal trash can, or in an open bonfire; it can be done with pots which have been previously bisque-fired, or with preheated dry burnished greenware. Here are demonstrations of firing in a small metal garbage can, placing a bonfire over an oil barrel, firing inside a kiln, and using cow manure (hmmm, better check your zoning!).
“I got your new book yesterday and couldn’t put it down…finished reading it this morning. Congratulations on such an outstanding job. The detailed and clear descriptions of the processes made me more confident about exploring beyond what I’ve picked up so far. There were new techniques that I now want to try. Some processes that I dabbled with 30 years ago became much clearer after reading the book, so I plan to revisit them as well. Add to all of that such a fine collection of photos, and I think you nailed it with this book!” – (unsolicited email testimonial from a reader to Sumi)
One of the most exciting ways to fire a burnished pot, pit firing allows pots to pick up black and grey marks from smoke and contact with combustible materials, but they can also pick up vibrant warm red, yellow and pink colours from chemicals added to the pit. There are as many ways to pit fire as there are potters who do it. Every potter ends up developing a personal style depending on variables like the type of clay used, the fuel available, the chemicals added and the altitude at which the firing takes place. A pit can be small enough for one person to fill it, or large enough for hundreds of pots, and you’ll find the methods demonstrated a great starting point for what you want to do.
A saggar is a lidded container used to contain and isolate a pot during its firing, and saggar firing has evolved as a way to achieve a result similar to pit-firing, but one pot or one kiln-load at a time. Saggars contain the fumes around a pot to allow the pot to pick up color. The requirements for saggar firing are minimal compared to pit-firing—a kiln, preferably gas rather than electric, is all you need. Sumi shows examples of artists using clay saggars and aluminum foil saggars as well as a raku kiln which would be fine for one or two pots.
Raku firing techniques
While there are many raku firing techniques, horsehair firing and naked raku are both simple, exciting and fun to try out. Here are the complete instructions for exploring both techniques successfully. With horsehair firing, the hairs do not even have to be from a horse as you can substitute a variety hair, fur and even feathers, from the animal kingdom. For the naked raku, with its distinctive raku crackle pattern, recipes and a complete description of the process are included.
Once a burnished pot is finished after firing, some potters like to enhance or protect the surface with some form of wax or acrylic coating. Some want to make their burnished pots even shinier, while others simply want to protect the surface from being stained by dirty fingers or accidental marks. You’ll find the type of finish that works best for you with this explanation paste wax, floor wax or tile sealer as possible alternatives.
About the author
Sumi von Dassow makes burnished pottery, teaches at a center for traditional arts, and runs occasional pit-firing workshops. She is a regular contributor and columnist for Pottery Making Illustrated and contributes articles to Ceramics Monthly as well. Her previous books include Barrel, Pit and Saggar Firing (2001) and Exploring Electric Kiln Techniques (2003) published by The American Ceramic Society.
A Review by Paul Wandless
I’m always happy to see new books on alternative firing methods and low-temperature firing techniques! Sumi von Dassow takes a focused approach with her latest book, using burnishing as the constant for all the processes covered. Her experiences as a writer, artist, and educator shine in how the information flows from a history of burnishing to its many techniques, then followed by the firing and finishing options.
She begins by addressing historical burnished pottery from China, the Mediterranean, Africa and North and South America, something that’s very nice to see. With the focus of her book revolving around this kind of work, providing a diverse and rich history of its use and development sets the stage well for the content to follow. I believe the more informed you are about the history and use of a technique, the better off you are in trying to incorporate and adapt it to your own work.
Von Dassow covers burnishing information to prepare the clay surface for all the low-firing techniques covered later. She gives advice for burnishing high-fire/stoneware clay, high-talc earthenware and leather-hard clay along with what tools and materials are most efficient. A wonderful 2-page compatibility chart matches burnishing approaches and low-firing techniques with different clay bodies. She then moves on to making, applying, and burnishing terra sigillata, and supplies recipes along with troubleshooting tips to assure good results.
Different firing techniques get the most out of a burnished surface and three chapters are dedicated to this. Each chapter includes full-color images of work that range from contemporary to indigenous pots. Assorted combustibles, colorants, materials, tools and firing chambers are well covered for each firing technique giving the reader plenty of options to choose from. Von Dassow also does a wonderful job offering several variations of each firing technique. I’m a big fan of exploring different variables within a given technique to achieve a more nuanced look.
In a chapter dedicated to smoke firing and black firing, Michael Wisner demonstrates a unique black firing method using a metal rack, manure, and a steel drum inside a gas kiln. Traditional indigenous techniques of the Mata Ortiz potters and Pueblo Native Americans for polychrome and black fired pottery are also demonstrated. A variety of pit firing methods in another chapter start from the basic small hole in the ground to firing in a large, deep pit. A Native American approach to firing out in the open on the ground is also featured.
A chapter on using clay and foil saggars in electric, gas and raku kilns includes different stacking methods and combustible/colorant combinations to yield a wide variety of results. Raku techniques for horsehair firing as well as naked raku are covered in their typical steps. The final chapter explains how to treat a surface after it’s fired, with paste wax, floor wax, tile sealer, varnishes, acrylic spray glaze, paint and gold leaf all shown as options.
Although low-firing is used in the title, it’s essentially an alternative firing book with burnishing as the theme to build most of the information around. Having this focus, though, is the book’s strength and what makes it different from other fast-fire and alternative firing books. The focus of the book is on the vessel, which could suggest that sculptural work isn’t appropriate for these methods. While there are a few challenges using these techniques, they are certainly suitable and widely used by clay sculptors. A pleasant surprise for me was the intentional inclusion of indigenous, cultural and historical information on many of these techniques, which are normally given little mention. This gives the book nice breadth within the subject matter.
Overall the book is thorough in covering the techniques in an approach that is easy to follow and apply, with lots of useful recipes, material suggestions and firing variants. Anyone interested in expanding their alternative firing repertoire will find this a valuable resource to add to their bookshelf. I know I’ll be adding it to mine. – Paul Wandless, Pottery Making Illustrated Nov/Dec 2009