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Kiln Pointers
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How Nearby Objects Affect Thermocouples |
CONTENTS How Nearby Objects Affect Thermocouples Recent Q&As: Deleting a program from a controller; correcting a programming error; the lid support design explained A Kiln Story: Once Afraid of Kilns Memorable Quote ----------- HOW NEARBY OBJECTS AFFECT THERMOCOUPLES The thermocouple, which measures temperature, is the small rod that protrudes into the firing chamber of a digital kiln. A kiln shelf or post that is too close to the thermocouple can affect the accuracy of the temperature measurement. This is because the temperature of the air inside the kiln can change faster than the temperature of a shelf or post. The thermocouple will read the temperature radiating from the nearby shelf or post as well as from the air. This can throw off the accuracy, especially if a shelf touches the thermocouple. A thermocouple has to be far enough into the firing chamber to read the temperature of the air rather than of the kiln wall. A thermocouple that has been pushed out of the firing chamber and into the wall can cause the kiln to overfire. This is because the temperature inside the wall is cooler than the temperature inside the kiln. Since the thermocouple is reading the cooler wall temperature, the controller will turn on the heating elements to raise the temperature. For these reasons, please follow these rules: 1) Keep shelves, posts, molds, and ceramic ware at least 1/2” away from the thermocouple. 2) As a general rule, the thermocouple should protrude into the firing chamber by four times its diameter. ----------- RECENT Q&As Q. I understand that the SC-2 kiln has 4 programs available. So, if I choose No.1 for my own program, for example batch annealing, would that automatically over-write the former one, since there is no delete button? A. The Sentry Xpress 4.0 controller stores five Single-Speed and four custom Ramp-Hold programs in memory. To select a program, press Start and then the Up Arrow key. Each time you press the Up Arrow, a different program number will appear. Select the one you want by pressing Start. Once you select a program number, entering a new program will erase the previous program associated with that number. Q. If I start programming and make a mistake, how do I go backwards? A. If you start programming and make a mistake, do not touch the keys for one minute. The Sentry Xpress 4.0 controller will erase the changes you made to the current program and go back to Idle. The original program will remain in memory, unchanged. Q. The lid prop bar on the left side of the kiln is hard to lock in. I have to wiggle the lid bar to make it fit securely. A. The aluminum lid support on the left side of the kiln locks into the extended position when the pin is inserted into the lid support hole. The pin has to be aligned with the hole before the pin can be inserted or removed. The alignment of the pin with the hole has to be precise, or the pin will not go in or out of the hole. The precise alignment of the pin with the hole is to prevent the pin from inadvertently coming out of the hole. Please raise the lid slightly before attempting to align the pin with the hole or to close the lid. I know smoother lid supports are available for other products. We have examined them. But we feel that they are not suitable for kilns, because they sometimes do no operate properly after they develop rust. ----------- A KILN STORY: ONCE AFRAID OF KILNS “After I first got my kiln, a Paragon A-11-9B-3, it took me a month or more to use it,” wrote Peggy Jones of Santa Cruz, California. “I was afraid that I would do something wrong and burn the house down. Well, I overcame my fear and am thankful for that. Over the years the kiln has become one of my best friends. “Out of necessity, I had to change the elements myself,” she explained. “Again, fear. I was able to complete the job without any problems because of the wonderful resources available from Paragon. Not only could I order the elements; I could also order anything else I might need like wires or switches. Several years ago I had to change bricks that were damaged during a house move. I was able to order and install those without any problems. “I guess what I am trying to say is that Paragon has always been there for me. With some companies today, once the kiln leaves the factory you are more or less on your own. I can honestly say that I will probably never buy from another kiln company. The people who work for Paragon that I have dealt with have always been very helpful and sincerely friendly. “I look at my little kiln now and have to laugh to think I was ever afraid of it. I am saving up for a much larger one with an electronic controller. How is that for progress!” Peggy, thank you for that beautiful letter. ----------- MEMORABLE QUOTE “The very basic core of a man's living spirit is his passion for adventure. The joy of life comes from our encounters with new experiences.” Christopher McCandless from the movie “Into the Wild” ----------- I am fortunate to be around people who exude creative energy. At the National Council on Education for the Ceramic Arts convention in Providence, Rhode Island three weeks ago, a young woman bought a Paragon Xpress-Q-11A glaze test kiln. I asked her, “Are you excited?” She smiled, brought her fists downward, and exclaimed, “I’m trembling!” It is always a joy to meet a Kiln Pointers reader. Two days ago at the Glass Craft & Bead Expo in Las Vegas, I was on an elevator with a small group of silent strangers. As I stepped out, a woman recognized my name badge and said, “I read your newsletter.” While someone else held the sliding doors open, she and I shook hands and smiled. Yesterday morning I arrived at the Dallas/Ft. Worth Airport from Las Vegas. The floor-to-ceiling windows at baggage claims showed dark clouds ringing the horizon. I went outside, where taxis streaked past. After three hours aboard a packed airliner, I felt exhilarated in the wind-lashed, cold rain. Nothing else feels quite like coming home after a long journey. Thank you, With best wishes, Arnold Howard Paragon Industries, L.P. – Better Designed Kilns 2011 South Town East Blvd., Mesquite, Texas 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 / ahoward@paragonweb.com / www.paragonweb.com / www.facebook.com/paragonkilns PRIVACY NOTICE: Under no circumstance do we share or sell your email address. Copyright 2015, by Paragon Industries, L.P. |
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