ceramic artsdaily.org techniques & tips for electric kilns inspiration, instruction and glaze recipes for making pottery in electric kilns This special report is brought to you with the support of Skutt Kilns and Pottery Wheels. Techniques and Tips for Electric Kilns Instructions and Glaze Recipes for Making Pottery in Electric Kilns Electric kiln firing is one of the most common firing methods because electric pottery kilns are readily available and simple to install. But that doesn’t mean that they yield common results. Electric pottery kilns can be incredible tools in the studio. The authors presented here are creative potters and ceramic artists using electric pottery kilns to create exquisite ceramic art. Not only can electric kilns produce great results, but they also offer control and dependability. And electric kilns keep becoming more versatile, economical, and easy to use with advances in controllers, energy efficiency, materials, and safety. Improve your electric firing results and take advantage of the incredible potential offered by electric kiln firing. How to Fire Electric Pottery Kilns From the Pottery Making Illustrated Instructor’s File Archives This introductory/refresher course covers all the bases of firing electric kilns. How to Clean Kiln Shelves, Mix Kiln Wash, and Apply Kiln Wash by Vince Pitelka Kiln shelf maintenance is a much hated but very necessary part of having a kiln. Neglected kiln shelves can result in flakes of kiln wash landing smack dab in the middle of a beautiful glaze surface. In this article, an excerpt from Clay: A Studio Handbook, 2nd edition, (due out Fall 2016) Vince Pitelka gives some tips on scraping kiln shelves, mixing kiln wash, and shares a couple of kiln wash recipes. Follow his advice and kiln wash flakes fused to a glaze will be a thing of the past! Glazing for Success in Electric Kilns by Jonathan Kaplan Layering and combining cone 6 glazes and using a controlled cooling cycle can create some exciting surfaces in an electric firing. Commercial Pottery Glazes Over Texture by Deanna Ranlett To get the most out of commercial pottery glazes in your electric kiln, you need to understand the product descriptions and of course test, test, test! Deanna Ranlett shares the results of testing some commercial glazes over texture. Slow Cooling in Electric Kilns by Deanna Ranlett Slowing down the cooling process in your electric kiln can prevent dunting and create some cool effects. Atmospheric-like Effects for Electric Pottery Kilns by Steven Hill Proving that a neutral or oxidizing atmosphere in an electric pottery kiln can produce exciting results similar to those in atmospheric kilns, Steven Hill focuses on layering glazes and a single-firing schedule. Start with his glaze recipes and firing schedule to get great success in electric kilns. www.ceramicartsdaily.org | Copyright © 2016, Ceramic Publications Company | Techniques & Tips for Electric Kilns | 1 How to Fire Electric Pottery Kilns From the Pottery Making Illustrated Instructor’s File Archives iring is the most critical part How Hot of the ceramics process be- 1 All clays and glazes are formulated to ma- cause it is the one thing that ture at certain temperatures. Firing clay makes clay durable, hence ce- F too high can cause it to deform or even ramic. Here are some of the principles melt, too low and it will not be durable. of firing and getting the best results Firing glazes too high can cause run-off with electric kilns. on the pot, too low and they will be dry and rough. To fire to the right tempera- From Mud to Ceramic ture, pyrometric cones are used. Cones are Firing converts ceramic work from made from various oxide mixtures and weak clay into a strong, durable, crys- bend at known temperatures (figure 2). talline glasslike form. Ceramic work In general, the following cones are used is typically fired twice: it is bisque in the pottery studio: bisque fire (cone fired and then glaze fired. The goal of 08–05), low fire (cone 06–04), mid-range bisque firing is to convert greenware (cone 4–7) and high fire (cone 8–10). to a durable, semi-vitrified porous stage where it can be safely handled Using Cones during the glazing and decorating Cones are used in process. It also burns out carbona- 2 every firing. Typi- ceous materials (organic materials in cally, a three-cone the clay, paper, etc.). As the tempera- system (either large ture in a kiln rises, many changes take or self-supporting), place in the clay. consisting of a guide cone that is one cone below the More Science target temperature, Heat in an electric kiln is transferred the firing cone and in three ways (figure 1): a guard cone (figure n conduction–heat transferred 3) provides the best through physical contact (1) information about n convection–heat rising through the firing. Bar cones the air (2) and small cones n radiation–heat emanating from are used in a properly adjusted Kiln- all the kiln elements (3). 3 Sitter®, an automatic shut-off device Electricity passing through coiled (figure 4). While the three large cones heating elements (made especially for are not required for kilns equipped with high temperatures) generates radiant a KilnSitter or an automatic controller, heat, which rises and is absorbed by they do provide a second point of refer- everything in the kiln. ence for how a kiln is operating. www.ceramicartsdaily.org | Copyright © 2016, Ceramic Publications Company | Techniques & Tips for Electric Kilns | 2 4 4 Get Ready cool or cold to the touch, it is not have a downdraft exhaust system, bone dry. Handle all work very care- prop the lid open, take the peephole Before firing any kiln, vacuum it out fully because it is extremely fragile plugs out and keep the temperature if necessary—bottom, sides, element at this stage. Place the bottom shelf below 212°F until all the moisture channels and lid. Check the elements on 1-inch stilts to aid circulation, is gone. Close the lid and check for for breaks, and chisel off any glaze and keep ware 1 inch away from moisture (hold a mirror or piece of drips on the shelves. Visually check elements, walls, thermocouple and glass up to the top peephole to see the electrical cords and connections. KilnSitter (figure 6). Unglazed pieces Make any repairs required (see own- may touch each other. Place a small ers manual or call your local supplier cone in the KilnSitter and/or a cone for service). pad on the middle shelf. Fire to Kiln Controllers cone 08–05, depending on the type Many electric kilns are now Kiln Furniture equipped with kiln controllers. Kiln An assortment of kiln furniture of clay and amount of porosity you want for glazing. controllers use a signal from a ther- (figure 5) is needed to hold and sup- mocouple (a sensing device that port ware during a firing. Furniture detects temperature) that’s located consists of shelves, posts, stilts and The Bisque Fire in the kiln. When the controller tile setters made from refractory ma- During the bisque firing a lot of senses the temperature, it com- pares this information with a com- terials. Kiln furniture is designed to damage can take place. Thicker puter program that tells the relays withstand the repeated heating and pieces with moisture or air bubbles to turn on or off. The relays control cooling to high temperatures with- create the biggest problem. Clay current going to the elements. Con- out deforming. needs to dry evenly through its trollers take the guesswork out of entire thickness. If the outside dries when and how high to turn up the The Bisque Load faster, it seals off the escape route for heat on the kiln. Because they are accurate at sensing temperature, Loading a bisque kiln is a fairly the interior moisture. The interior they are more efficient than man- simple task, but there are some moisture turns to steam and forces ually-fired kilns. They come with basic rules. Fire full loads to take its way out (explodes) during the preset programs, or you can even advantage of conduction heating bisque. To avoid this, start off slowly easily input programs to adjust to and also save electricity. All work when firing a bisque kiln. Turn on special firing requirements. should be bone dry. If the work is one element to low. If you do not 5 6 7 www.ceramicartsdaily.org | Copyright © 2016, Ceramic Publications Company | Techniques & Tips for Electric Kilns | 3 if it fogs up). Turn on all elements wash becomes bumpy and should What’s That Smell? to low for at least an hour then to be cleaned off with a chisel. All medium for an hour before turning glazed pieces must be checked to Clay and ceramic materials change all elements on to high. The firing is make sure there is no glaze touch- their chemistry when fired. Car- done when the firing cone falls. ing the shelf. Coat with wax at bonaceous materials burn out least ½ inch from the bottom of between 500°F–1450°F. Firing The Glaze Fire the piece. Sort work by height and clay materials in electric and gas Vacuum the kiln, especially if place on shelves with a minimum kilns produces carbon monox- any pieces exploded during the of ½ inch between pieces and 1 ide, formaldehyde, sulfur dioxide bisque. When firing glazed pieces, inch from the walls, elements and gases, and more. Some of the by- make sure there is a thin coat- KilnSitter. Turn the kiln on low products are harmful so vent kilns ing of kiln wash (available from for about an hour and then me- to the outside.