CERAMICS MONTHLY CERAMICS
focus MONTHLY
innovation
June/July 2006 June/July
$7.50 n , 9 an$ C ( 0 5 . 7 $
h
eaisotl org . ceramicsmonthly . w w w ) 0 5 . 6
focus innovation
JUNE/JULY 2006 $ 7 . 5 0 ( C an$ 9 , E6 . 5 0 ) w w w . ceramicsmonthly . org
“The Bailey is an awesome performer!”
“I bought my Bailey Shuttle PRO 40 back in 1995. I love this kiln! I have logged in almost 500 firings now. It has been an awesome performer. The quality of the work coming out has been consistent and top notch. Also, it’s easy to fire and the fuel economy has been exceptional.
“Recently I needed to make some repairs to the lining of the kiln. The fact that the kiln can be so easily repaired is great and has given me another level of appreciation for its design. The dry stacking and anchoring of the bricks is bril- liant. Bailey really thinks out every detail so you get the most from your kiln.
“I really appreciate being able to talk to Bailey’s technical staff. Any question is quickly answered. I can’t say enough about these kilns. ”
Peter Flanagan, Okanagan Pottery, Peachland, BC, Canada
Think Bailey for the Best in Downdraft Design www.baileypottery.com
Bailey Pottery Equip. Corp. PO Box 1577 Kingston NY 12401 Professionals Know www.BaileyPottery.com • TOLL FREE (800) 431-6067 Direct: (845) 339-3721 • Fax: (845) 339-5530Ceramics Monthly June/July 2006 the Difference. 1 MONTHLY
Editorial [email protected] telephone: (614) 895-4213 fax: (614) 891-8960 editor Sherman Hall assistant editor Renée Fairchild assistant editor Jennifer Poellot technical editor Dave Finkelnburg publisher Charles Spahr Advertising/Classifieds [email protected] (614) 794-5809 fax: (614) 891-8960 classifi[email protected] (614) 794-5866 advertising manager Steve Hecker advertising services Debbie Plummer Subscriptions/Circulation customer service: (800) 342-3594 [email protected] Design/Production design Paula John production Jami Flannelly Editorial and advertising offices 735 Ceramic Place, Suite 100 Westerville, Ohio 43081 USA Editorial Advisory Board Linda Arbuckle; Professor, Ceramics, Univ. of Florida Tom Coleman; Studio Potter, Nevada Dick Lehman; Studio Potter, Indiana Meira Mathison; Director, Metchosin Art School, Canada Don Pilcher; Potter and Author, Illinois Bernard Pucker; Director, Pucker Gallery, Boston Phil Rogers; Potter and Author, Wales Jan Schachter; Potter, California Mark Shapiro; Worthington, Massachusetts Susan York; Santa Fe, New Mexico
Ceramics Monthly (ISSN 0009-0328) is published monthly, except July and September, by The American Ceramic Society, 735 Ceramic Pl., Suite 100, Westerville, Ohio 43081; www.ceramics.org. Periodicals postage paid at Westerville, Ohio, and additional mailing offices. Opinions expressed are those of the contributors and do not necessarily represent those of the editors or The American Ceramic Society. subscription rates: One year $34.95, two years $59.95. Canada: One year $40, two years $75. International: One year $60, two years $99. back issues: When available, back issues are $7.50 each, plus $3 shipping/handling; $8 for expedited shipping (UPS 2-day air); and $6 for shipping outside North America. Allow 4–6 weeks for delivery. change of address: Please give us four weeks advance notice. Send the magazine address label as well as your new address to: Ceramics Monthly, Circulation Depart- ment, P.O. Box 2107, Marion, OH 43306-8207. contributors: Writing and photographic guidelines are available online at www.ceramicsmonthly.org. indexing: An index of each year’s feature articles appears in the December issue. You may also visit the Ceramics Monthly website at www.ceramicsmonthly.org to search an index of article titles and artists’ names. Feature ar- ticles are also indexed in the Art Index, daai (design and ap- plied arts index). copies: Authorization to photocopy items for internal or personal use beyond the limits of Sections 107 or 108 of the U.S. Copyright Law is granted by The American Ceramic Society, ISSN 0009-0328, provided that the appropriate fee is paid directly to Copyright Clearance Center, Inc., 222 Rose- wood Dr., Danvers, MA 01923, USA; (978) 750-8400; www.copyright.com. Prior to photocopying items for class- room use, please contact Copyright Clearance Center, Inc. This consent does not extend to copying items for general distribution, or for advertising or promotional purposes, or to republishing items in whole or in part in any work in any format. Please direct republication or special copying permission re- quests to the Publisher, The American Ceramic Society, 735 Ceramic Pl., Suite 100, Westerville, Ohio 43081, USA. postmaster: Please send address changes to Ceramics Monthly, P.O. Box 2107, Marion, OH 43306-8207. Form 3579 requested.
Copyright © 2006 The American Ceramic Society All rights reserved
www.ceramicsmonthly.org
Ceramics Monthly June/July 2006 2 Seth Rainville Don Ridley [email protected] [email protected] At the Phoenix Center for the Arts Ceramics Department, Resident Artist Seth Rainville and Instructor Don Ridley teach over 100 students each 14-week session. “Our students have high expectations and our Geil DLB 30 delivers. We fire to Cone 10 about once a week with over 20 different glazes on various clay bodies, and our kiln consistently produces great results time and time again. “When you’re firing everything from paper-thin porcelain to thick sculptural work, with copper reds and carbon trap shinos all in the same load, it’s great not to have to worry about even reduction or top to bottom temperature difference. And the durability and ease of operation are two additional reasons why this 10-year-old Geil is still the work horse that it has always been, and why we wouldn’t use any other brand.”
For information on the Phoenix Center for the Arts, visit www.phoenix.gov/parks. GEIL KILNS 7201 CLAY AVE. HUNTINGTON BEACH, CA 92648 800-887-4345 • Fax: 714-847-6145 • [email protected] Check Out Our Complete Line of Gas & Electric Kilns at www.kilns.com
Ceramics Monthly June/July 2006 3 How long does your kiln last? Easy-Fire kilns are durable, easy to use, easy to service & come with a Three Year Warranty. Hard Ceramic Element Holders Make the Difference!
Call - 877.HOTKILN L&L Kiln Mfg., Inc. PO Box 1898, 8 Creek Parkway, Boothwyn PA 19061 PHONE: 610.485.1789 or TOLL FREE: 877.468.5456 FAX: 610.485.4665 EMAIL: [email protected] WEB: www.hotkilns.com Ceramics Month ly June/July 2006 4 JUNE/JULY 2006 / Volume 54 Number 6
MONTHLY focus innovation
30 Lattice Structures by Jesse Hull with Orchestrating Aesthetics: Balancing Form and G laze by John Tilton, Seeding Precedence: The Basics by Fara Shimbo and Re-envisioning Traditional and Modern V iews by Jo Yi-Hyun Crystalline-glaze gurus and enthusiasts gather in K ansas City, Missouri, to discuss technical and artistic concerns. 34 Hai Kaburi Creating Consistent Crusty Wood-Fire Results by Lee Middleman
38 Glaze Forward by Diana Pancioli A lending library of test tiles allows hands-on exploration of Cone 6 reduction glaze surfaces. recipes Cone 6 Reduction
41 A Hybrid Kiln for Hybrid Surfaces by Dave Zdrazil Students and teachers build a gas- and wood-fueled salt kiln that produces a wide variety of surfaces. features 44 Heads and Horses The Ceramic Work of Jean-Pierre Larocque by Andy Nasisse 48 Amy Lemaire G lass as G laze by Elizabeth Reichert monthly methods Mastering Clay and G lass Fusion
52 Horsehair Raku by Bob Hasselle A post-firing reduction process helps a potter develop an aged patina to match his neolithic imagery. monthly methods The Horsehair Process recipe Riggs Terra Sigillata 54 The Dark Side of Athanasius by Brian Fiorentino 30 Perserverance and detective work eventually pay off in an artist’s attempt to restore a cathedral’s eighty-year-old custom tile floor. monthly methods Custom Tile Cutters recipes Tile and Saggar Bodies
cover: Untitled, 99 cm (39 in.) in height, slab-, coil- and hand- built, with thin, textured slabs thrown onto the surface, glaze, 2006, by Jean-Pierre Larocque, Montréal, Québec, Canada; XX48 34 XXXX 38 page 44. Photo: Bertrand Carrière.
Ceramics Monthly June/July 2006 5 departments 10 from the editor
12 letters from readers
14 answers from the CM technical staff
18 suggestions from readers 18 Tip of the Month: Make a Name for Yourself
20 upfront reviews, news and exhibitions 58 call for entries 58 International E xhibitions 58 United States E xhibitions 60 Regional E xhibitions 60 Fairs and Festivals 62 new books 70 calendar 70 Conferences 70 Solo E xhibitions 74 G roup Ceramics E xhibitions 75 Ceramics in Multimedia E xhibitions 78 Fairs, Festivals and Sales 79 Workshops 84 International E vents 93 classified advertising 95 index to advertisers 96 comment Super Iga by W. Lowell Baker
online www.ceramicsmonthly.org current features, expanded features, archive articles, calendar, call for entries and classifieds XX special listings 24 G allery G uide Where to see ceramics in the U.S. and abroad Residencies and Fellowships Full listing of professional-development opportunities Summer Workshops 2006 E verything you need to plan an educational getaway
26 22 24
Ceramics Monthly June/July 2006 6 Ceramics Monthly June/July 2006 7 You name it, we’ve got it! Best prices. Best service. Best Selection. www.baileypottery.com is your source!
June Lowest Prices! Special Offer In addition to our on- line sale price, receive an additional Gift Certificate with Bailey Bailey selected Bailey Wheel PRO-X Series ST-X Series Models. 1 Piece Counter Pan 2 Piece Counter Pan SHIMPO Go on-line to see the full range of Bailey Wheels and professional accessories at unbeatable prices. In-Stock ready to We also sell Shimpo, Brent, Creative Industries, and Lockerbie at unbeatable prices. ship.
Bailey Mini Might Rollers Low Cost! June On Special Offer Sale
16" or 22" In addition to our on- Wide Slabs line sale price, receive an additional New! Gift Certificate with Basic 30 with “I couldn’t do it selected Slab Roller Super Affordable! gear reduction without my Bailey” Models. Bailey DRD/II
For 30 years, Bailey has been the innovative force in slab roller design. Our world famous slab rollers are totally dependable, durable and easy to use. Ask any professional what they prefer and you will get a quick response...”Bailey is the Best”.
On On Sale Sale
Low,Low Fume Vent Systems Prices Bailey Extruders are the #1 choice of ceramic artists like Bill Shinn. Bailey has all the Look to Bailey for the best selection of HEPA Vacuums professional features that demanding potters require for the ultimate extruding experience. Choose and Air Filtration. from 6 models, assorted dies, and extruding fixtures. On Sale
Check out our new line of Bailey has the largest Super Discounts van Gilder Bailey has the best storage pugmills that extrude tile selection of tools from Professional Hand Tools solutions and studio furniture. and our efficient Kemper, Sherrill, Jepson, on Glazes & mixer/pugmills. Bailey,& more! CeramicsStains Monthly June/July 2006 8 New! Nitride-Bonded Bailey is your kiln shelf Silicon Carbide headquarters! High-Alumina Advancer
Our new Nitride-Bonded Silicon Carbide shelves Our High Alumina shelves are Advancer is light as a feather are light weight, offer exceptional strength at fantastic in both gas and elec- and stronger than any other Cone 11, include unique stress relief joints for tric firings. Rated for Cone 11. shelf. Rated for Cone 16! long life, and superior glaze release properties. Available in all popular sizes. Check out our low, low prices. Call for a quote. We will beat any price.
Bailey Double-Insulated True Cone 10 Kilns Bailey Electric’s Save electricity, extend element life by 30%, fire Commercial Duty evenly top to bottom, and fire dense loads with ease. Front Loading or Shuttle These are just a part of the benefits of firing with a Bailey. 7” Insulated Walls 8 Step 3 Zone Controllers Massive Industrial Elements Save Electrical Costs! Custom Designs Features: Affordable Prices Massive Elements 3.5” Double-Insulated Walls Bailey gives you Elements in the Floor Easy Access Control Panels FREE FREIGHT 3 Zone 8-Step Controller FREE Gift Certificate, Super Heat Distribution & LOW LOW PRICES on all 4 kiln packages. Sizes: 3.3 cu. ft., 16 1/2” cu. ft., OVAL with Counter Weight 7 cu. ft., 10 cu. ft. Get more for your money!
Get FREE FREIGHT and a LOW PRICE on any Bailey Cone 10 Top Loader kiln shipped anywhere in the contiguous US when ordered with a Dawson kiln sitter, Bartlett Controller, & a High Alumina Furniture Kit. Call for details and conditions.
22% off our Huge Selection Bailey Ceramic Supply of Books & 10% off Videos. Toll Free 800 431-6067 There is no minimum! See the complete PO 1577 Kingston, NY 12402 (845) 339-3721 Fax (845) 339-5530 selection in our color catalog or web site with informative reviews and descriptions. Our web site is continually web: www.BaileyPottery.com updated with the latest releases. e-mail: [email protected]
Ceramics Monthly June/July 2006 9 from the editor
You may have noticed that you are read- though it is arguably one of the oldest project. The CM readership has widely ing the June/July issue of CM, rather creative human endeavors, is to this day varying areas of specific interest, but we than the usual June/July/August issue. rife with artistic and technical innovation. all share an excitement for clay as a cre- We’re doing this, along with an August/ Whether the topic is glazes, kiln design, ative endeavor, and that requires constant September issue, in order to shorten the use of materials, or forming methods and innovation. We all must come up with “summer CM drought” you are no doubt techniques, ceramics begs us to innovate. better ways of doing things, continually begrudgingly accustomed to enduring. Certainly, there is proof of innovation improving what we do and how we do it. This is just one of CM’s innovative new beyond the scope of the articles presented Sometimes it’s a matter of survival; some- ideas; it is only fitting, therefore, that it is in this issue, and just because it is already times ambition, restlessness, boredom, launched in conjunction with an issue in your hands doesn’t mean you can’t compulsion—you get the idea. So let me focused on innovation. Ceramics, even send me your innovative process, idea or know what you are up to. Go to www.ceramicsmonthly.org and click on “Letter to the Editor,” or send an e-mail to [email protected]. In addition to inviting input from the entire CM readership (and at the risk of overloading my Inbox), I would particu- larly like to invite students to contribute to Ceramics Monthly. We’re all involved in education in one way or another, and I’m interested in hearing about the all- too-often overlooked perspective of the ceramics student. One can be a student in any number of capacities, at a multitude of academic and nonacademic institutions, experienc- ing real learning and growth through a wide variety of educational models. Be- cause of this, I don’t want to get too narrow in what I’m asking for, so I’ll start with what I don’t want: I don’t want your artist statement. That is to say, if your artist statement is anything like mine was as a student, leave it on your hard drive. Write a student statement and send it to me. Explore your current education not in terms of where you want to end up but where you are. As students, we are re- quired to reach beyond our boundaries, stretch our minds and expand our poten- tial. This is as it should be; it’s part of what a good education is about. But being a student is, in and of itself, a sin- gular experience. This is the perspective I am looking for. Think about this as an opportunity to be the instructor. You are an expert on the topic of students, and you are fully qualified to teach on the subject.
Sherman Hall, Editor
Ceramics Monthly June/July 2006 10 ingredients: loafer's glory, orangestone, riverside grit, helios, stan's red and lyman red. =e7^[WZ$Jh[WjOekhi[b\$
asheville, nc 828.252.6033 www.highwaterclays.com st. petersburg, fl 727.553.9344
Ceramics Monthly June/July 2006 11 letters
Marketing Pots Of course, each person’s experience is Carol B. Eder’s thoughts on food and pots different, and no doubt there are plenty of [ April Letters] made me think of interesting glazes that will end up looking the same, ways two rogue colleagues and I show our especially a commercial gloss. I felt obliged pots at sales events. We set the table with a to share my results, because I am sure they velvet tablecloth and napkins, silver cutlery, are not unique. fresh fl owers and, of course, ceramic place David Ross, Sonoma, CA settings, serving pots and platters. The soup bowl holds clay buttons, which we call stone soup. We find that the pots walk away What Do You Think? as soon as you paint pictures, use humor • What discovery have you made through ex- and have fun. perimentation that disproves a “rule” you were My card states “Great art won’t match taught? E-mail comments (with your full name the couch,” but an amazing casserole will and address) to [email protected]. speak to the roasted asparagus! It gets the attention that I want for sales. Lynda F.R. James, Sudbury, ON , Canada Bronze and Clay In response to the May Letters question about other materials infl uencing claywork: What Do You Think? My excursion into bronze has been • What is the most humorous sale you ever exceedingly beneficial to my clay pieces. made? E-mail comments (with your full name While creating clay figures in various poses, and address) to [email protected]. I was always making a standing person with lots of cloth to support the lower half but Firing Foible wanted to explore an alternative to this I would be remiss not to challenge some- bulky solution. I chose the medium of thing in the Comment by N ils Lou (“the bronze, which had the strength to support Slippery Slope,” F ebruary CM). He states the weight of the body with bare ankles. that there is no reason not to fire your kiln After this bronze experience, I had a as fast as possible, adding a longer soaking compelling need to try standing figures in period at the end if necessary. Although this clay and chose a slim body to reduce the was my own logic for many years, experi- weight of the medium on the legs. With a ence and contrary advice from another successful initial firing, I have gradually person finally set me straight. increased the volume of the forms with- I fire a variety of matt and gloss glazes to out incident. Cone 8 – 9 and was having particular prob- Each of my early works had a different lems getting consistently smooth, fl awless, color, which evolved from adding oxides to rich surfaces with the matts. I extended the the clay. This method also caused the color time for the last couple cones by hours, yet of individual pieces to be uniform. was still plagued with dry areas and some When interesting hues developed from pinholes. N o amount of glaze formula the application of chemicals to the finished manipulation seemed to make a difference. bronzes, I decided to casually apply oxides F inally, I consulted with someone. I to the fired clay, and enjoyed the variety of resisted his advice because it seemed counter colors and values that came from the ran- intuitive. He told me that a slow rise in domness of the process. temperature from bisque to Cone 8 would Norman Holen, Minneapolis, MN provide a far superior glaze melt than slow- ing down at the end, or even extended Correction soaking at the top cone. He recommended On page 4 3 of the April issue [ “Jan taking about six hours to get from Cone 0 6 Schachter: P otter,” by Linda Mau] , the to Cone 8 . recipe for Black Oak Wood Ash Glaze All I can tell you is that, after years of included an addition of Bentonite listed at frustration with less-than-ideal results, this 2 0 % . That amount is actually 2 % . We new schedule solved all my problems. N ow, apologize for this typographical error. I only deal with questions of application and formula alterations, knowing that each Read more Letters online at www.ceramicsmonthly.org/letters. firing will be excellent. The glazes are abso- Submit letters by e-mailing [email protected]. In- clude your full name and address. Editing for clarity or brevity may lutely affected by the firing speed long take place. Letters also can be mailed to Ceramics Monthly, 735 before they actually look like glaze. Ceramic Pl., Suite 100, Westerville, OH 43081. Ceramics Monthly June/July 2006 12 Ceramics Monthly June/July 2006 13 2006 CERAMIC answers From the CM Technical Staff
WORKSHOPS Q How can I produce a high shine on the careful drying to the leather-hard stage is impor- surfaces of pots that I’m pit firing, similar to tant in preventing smudging and smearing of the Fire & Smoke those produced in the American Southwest? I decoration. It is important, however, that you Tim Scull have tried wax and polish, but I am worried that apply the slips at a soft leather-hard stage to ensure $ Tuition: 285 those won’t be permanent.—L.T. that they will fully adhere to the clay body. June 17, 18 The shine on the surface of the pots found in P ottery that has a combination of matt and Unload: June 19am many parts of the world, including the American glossy areas on the same piece is produced by Southwest, is simply a result of burnishing the burnishing the entire piece, then painting a thin Crystalline Glazes surface of the work during the leather-hard stage. layer of slip on the portions of the work you want Tim Scull Burnishing is a rather simple technique. There to be matt. Tuition: $225+clay are only a few basic requirements of the object and You will find that burnishing is much more July 29, August 26 clay to make the technique work for you. The first noticeable at temperatures below Cone 0 4 . The is simplicity of form. You can burnish almost any clay surface tends to look denser (even vitrified) at Wood/Salt Firing clay surface, but delicate, highly undulating, or higher temperatures. This generally does not show Tim Scull textured surfaces will not respond well to burnish- off burnishing as well as lower temperatures. Tuition: $385 ing. The second requirement is a clay body that has W. Lowell Baker June 22, 23, 24 a high percentage of fines (small clay particles) and Professor of Ceramics Unload June 25am a low percentage of grog, sand, or larger clay University of Alabama particles. If you choose to use a coarse clay body, Functional then you can coat the surface with a fine-grained Q Could you give an estimate of the amount of Altered Pots slip or terra sigillata [ see Word of the Month on propane gas used in a sprung-arch updraft kiln Sarah Gross page 1 6 ] . Terra sigillatas and slips also offer you the with the approximate interior dimensions of Tuition: $225+clay opportunity to alter the color of your clay surface, 36x36x42 inches, one course of K23 insulation July 8, 9 as in the case of many of the Southwestern pieces brick, with 2 inches of fiber blanket backing? you may have seen. The kiln is fired to Cone 10. I would be using four Fearless Electric As the clay is drying, it will change from the venturi burners rated at 77,400 Btus, each at 11 Firings plastic state to a soft leather-hard stage. At this inches WC (water column) pressure.—J.F. Tim Scull & the Bailey point, you will want to begin smoothing the sur- Your question cannot be answered definitively Pottery Equipment face of your work in preparation for burnishing. I because many variables affect the possible ranges. Company like to use a hard plastic or steel rib to compress the The short answer is that your kiln could be fired to $ Tuition: 110, July 16 surface. D rag the rib across the surface at an angle Cone 1 0 with as little as 1 9 gallons of LP G or as Throwing & that compresses the clay rather than scrapes or much as 1 0 0 . Here’s why: Individualizing planes the surface. The weight of the kiln load (not the dimensions Large Functional Let the work dry to a point where no soft of the kiln) will determine the amount of Btus Forms clay sticks to your dry finger when you rub it across required. This weight includes kiln furniture, bag Bob Crystal the clay. I prefer to dry my work in a tightly sealed walls and any hardbrick interior, as well as the ware plastic bag for two days to a week. This slow drying Tuition: $225 itself. Your firing protocol will also dictate gas July 22, 23 ensures that the clay is evenly dried to a hard leather- usage. And finally, combustion efficiency will af- hard consistency. Once the work is sufficiently dry, fect everything. F or example, if you start with a Five Days of Fire you can start the burnishing process. candling overnight, that will use a lot of fuel, not to Wood, Salt, Gas, Saggar There are several tools that work well for bur- mention time. Saturating the kiln with heat will Tim Scull & Staff nishing; try a stainless steel spoon, a highly polished diminish the K -factor of the insulating walls so you Tuition: $485 rock or a hard plastic bag pulled tightly over your will use more fuel to get to temperature than if you August 7-11 finger. (Choice of plastic bag is an art in itself; some heated rapidly. work and some don’t.) Simply rub the stone, etc. To fire efficiently, fire rapidly. As long as you Form & on the surface of the clay. You will note that the are firing work that has already been bisqued, start Contrast mark left by the stone is slightly glossier than the and continue with the burners on full. Set the Tom O’Malley surrounding clay. You simply try to cover the damper open until Cone 0 1 0 , then adjust for a $ Tuition: 225+clay entire object with these glossy marks. To achieve slight reduction atmosphere (assuming you want a August 19, 20 a higher luster, you can then change the direc- body/glaze reduction). A slight fl ame at the ports tion of your rubbing and cover the object again. will begin at around 1 8 0 0 °F (9 8 2 °C). You want to For detailed info and to register: The burnished finish is best achieved using the avoid carbon and smoke. www.cantonclayworks.com plastic bag. To set your burners for efficient combustion, Through trial and error, you will learn the best turn the burners on to full pressure and, with the Canton Clay Works llc, stage of dryness at which to burnish your work. If door open, observe the fl ame while someone ad- Canton, Connecticut you are adding slip or terra sigillata decoration, justs the primary air disk on your atmospheric (860)693-1000 Ceramics Monthly June/July 2006 14 Ceramics Monthly June/July 2006 15 answers burners. When each burner has a predominantly F or a detailed discussion on combustion, burn- faster, resulting in a drop in pressure at the constric- blue fl ame with a minimum of yellow, and all four ers and Btus, refer to chapters three and four in my tion. This effect is known as Bernoulli’s P rinciple, are the same, tighten the locknut on the disk. Your book The Art of Firing. based upon the mathematical description by the burners will now be set for neutral combustion. Nils Lou eighteenth-century Swiss scientist D aniel Bernoulli. Changing the atmosphere can then be done with Willamina, OR The type of gas burner known as a V enturi the damper, as it affects the introduction of second- burner (also called an inspiriting or atmospheric ary air for the desired degree of reduction. Q W hat is the V enturi effect that is referred to burner) is designed with a constriction or “neck” in In summary, don’t candle bisqueware, don’t in descriptions of gas burners and in discussions the burner tube that causes the gas entering the ramp up slowly, fire with burners set for neutral of fuel- burning kilns? — P . S . back end of the burner to speed up as it passes combustion (don’t over-reduce), and stack loosely A V enturi is a constriction in a tube or pipe that through the neck. This results in lower pressure so the heat can move through the kiln. causes liquid or gas fl owing through the pipe to fl ow(suction) that draws in air from outside of the burner through the adjustable air ports or gap near the back end of the burner. This air (known as “primary” air) mixes with the gas in the burner and provides for combustion at the burner outlet. This same principle was used for years in the automobile carburetor. Air drawn in through the carburetor passed down through a constriction (the carburetor throat) where the resulting lower ³,KDGDOZD\VXVHGP\RZQJOD]HUHFLSHVEXW pressure drew in gasoline that mixed with the air 6SHFWUXP¶V5DNX*OD]HVJDYHP\ZRUNVRPH and passed to the cylinders. H[FLWLQJQHZGLPHQVLRQVDQGWKH\DUHVR The term Venturi effect has also been used to describe certain design features in fuel-burning FRQYHQLHQW´,DQ&KXQJ kilns, such as constrictions in the exhaust fl ues, which are claimed to create localized regions of lower pressure and improved fl ow or mixing. In many cases, this is an overgeneralization or misuse of the term, and the effects claimed are not actually due to the V enturi effect. Phil Berneburg Bethesda, MD
Word of the Month
Terra Sigillata Terra sigillata (Latin for “sealed earth”) is a very dilute slip or suspension of extremely fine clay particles in water generally applied as a coating on leather-hard pottery in order to change the color, and provide a smooth surface that can be burnished and polished to a high shine. It was used on the ancient Greek red-and-black pottery and R oman redware, as well as in pre-Columbian Central and South America. It is prepared by allowing a defl occulated (dispersed) clay suspension to stand in a container until the coarse particles have settled to the bottom, leaving only the finest clay particles remaining above in sus- )RU'HWDLOVRQKRZ,DQPDGHWKHSRWVJRWRRXUZHEVLWH pension. Typically, a layer of clear water will KWWSZZZVSHFWUXPJOD]HVFRP also appear at the top; this is removed before siphoning off the cloudy middle layer (the 2XU1HZ$GGUHVV)HQPDU'U3KRQH terra sigillata layer) for use. 7RURQWR21 If you have a question about this or any other ceramics topic, ask &DQDGD )D[ the CM experts at [email protected]. You also 0/0 (PDLOLQIR#VSHFWUXPJOD]HVFRP can mail questions to Ceramics Monthly, 735 Ceramic Pl., Suite 100, Westerville, OH 43081; or fax to (614) 891-8960.
Ceramics Monthly June/July 2006 16 Ceramics Monthly June/July 2006 17 suggestions
Getting to the Point ’ ’ fi fi fi “ ” —Rick Erickson, Green Bay, VA fi Tip of the Month Make a Name for Yourself fl fl