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Kiln Pointers
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A Pre-Firing Checklist |
CONTENTS A Pre-Firing Checklist Recent Q&As: An element that remained pliable after firing; determining a kiln’s kilowatts A Kiln Story ------------- A PRE-FIRING CHECKLIST Recently a customer thought her kiln needed a new controller, because the heating elements wouldn’t turn on. But after several days, the kiln surprised her; the relays began clicking, and the elements hummed. Upon investigation, she discovered that a delay start of 99 hours and 50 minutes had been programmed into the kiln. She asked her little six-year-old granddaughter if she had played with the kiln. The child hesitated and then said the cat might have touched it. That little story has two lessons: Don’t panic when something goes wrong with your kiln. The solution might be far less expensive than you imagine. And second, follow a pre-firing checklist. It saves time and prevents errors. Pilots use pre-flight checklists. My traveling checklist has saved me many hours over the years trying to remember everything to pack. I keep copies of it in a file folder. A checklist is especially useful if you don’t fire your kiln often. Customize this checklist to fit your particular needs: General Checklist--- Remove flammable materials from the firing room. Make sure the plug is pressed all the way into the wall outlet. Check the plug and outlet for signs of heat damage. Vacuum the kiln before firing glazes or glass. Digital Kiln Checklist--- Make sure the thermocouple extends the correct distance into the firing chamber. (It is easy to bump the thermocouple with a shelf.) Top-loading kilns: Look inside with a flashlight to make sure the ware or a shelf is not too close to the thermocouple. Use Program Review to compare the actual program with a written program. Kiln Sitter Checklist--- Make sure you are using the correct pyrometric cone number. Remove chairs or other objects that could get pushed against the Kiln Sitter and prevent the weight from dropping. Top-loading kilns: Look inside with a flashlight to make sure the ware or a shelf is not too close to the Kiln Sitter tube. Make sure the cone is centered properly on the cone supports. Check this just before you close the lid. ------------ RECENT Q&As Q. I have always being told that elements that have been fired and come out of the brick groove are brittle. It was understood that you pinch them with a pliers only after they are heated. Last week I was stripping the elements out of an old kiln. These elements had been fired many times, yet they were pliable and springy. I feel I could have comfortably stretched or squeezed them without the fear of breaking them. So when I have sagging elements, why can't I simply squeeze areas with pliers and reset them back in the element groove? Why heat the element? Just how brittle is an element after firing? A. Iron chrome elements become very brittle after they have been fired. They easily break if bent while cold and must be heated with a propane torch until the section you are bending glows red. Nickel chrome elements, on the other hand, are far more pliable after they have been fired. They can be bent while cold. But even nickel chrome elements are fragile. Place a small magnet near the element to tell which type you have. The iron chrome attracts the element; the nickel chrome does not. Q. How does one determine the kilowatts that the kiln draws? A. Look at the kiln's electrical data plate. It is usually on the side of the switch box. The data plate lists the watts, amps, and volts. Divide the wattage of your kiln by 1000, which gives kilowatts. --------------- A KILN STORY Sylvia Hoyman of Anchorage, Alaska wrote, “When I got my kiln I had a big talk with my two- and four-year-old kids about the dangers of a hot kiln. A year later the four-year-old still warns ME every time I open the kiln, "Mom, you be careful. That can be hot!" --------- If you have a minute, please answer our kiln survey. I would appreciate hearing your opinion. The survey link is in the center of our home page at www.paragonweb.com . I hope you are enjoying your summer or for those in Australia, your winter. Thank you, With best wishes, Arnold Howard Paragon Industries, L.P. – Better Designed Kilns 2011 South Town East Blvd. Mesquite, TX 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 ahoward@paragonweb.com / www.paragonweb.com PRIVACY NOTICE: Under no circumstance do we share or sell your email address. Copyright 2008, by Paragon Industries, L.P. |
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“Custom and standard Kilns and Industrial Furnaces for ceramics, pottery, heat treating, enameling, |
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