A lid cutoff switch can be factory-installed on most kilns and is easy to adjust.
Difficult Problems, Simple Answers
Recent Q&As: Dark spot in an element groove; reasons elements fail; no crimping tool needed to change elements; reason for fumes during first firing of a ceramic fiber kiln.
Sometimes mysterious problems have simple answers. When the digital temperature display is blank, make sure the kiln is plugged in. When an element stops firing, don’t replace it until you have checked for a disconnected wire. Dave Coggins offers two examples of problems that have simple answers, one easy and one difficult. (The lid safety switch he discusses is required in certain parts of the world and can be factory-installed on most kilns.)
Dave is a retired kiln technician in Queensland, Australia.
DIFFICULT PROBLEMS, SIMPLE ANSWERS
By Dave Coggins
I occasionally miss working on kilns. There was always a challenge to solve some of the more way-out problems. I rarely found one I couldn't solve, albeit after a few sleepless nights.
I think my favourite difficult kiln problem with a simple answer was where the kiln would cut out half way through firing for no apparent reason. Everything checked OK--no bad connections, plenty of power to the elements, controller and thermocouple OK. It drove customers crazy.
The solution was in the door or lid safety switch adjustment. It was fine when the kiln was cold, but as the door or lid heated and expanded, the movement would open the safety switch and cut the kiln off. A simple adjustment would fix the problem every time.
A problem which I found most difficult to explain to customers happened when they moved their kiln from one location to another, and the kiln wouldn't reach temperature any more. They would say, "But it worked fine at my last place. Why won't it work now?" I would try to explain that their elements might be a bit tired, and there wasn't as much power available at their new location, etc., etc., only to hear, "But it worked fine at my last place. Why won't it work now?" This problem was difficult to solve, because it usually involved electricians and power supply authorities. I had a few cases where the customer just couldn't use the kiln until the supply authority installed a new power transformer in their street. Sometimes that took months.
Q. An element burned out and left a dark area in the element groove. What is that dark area?
A. The dark area is contamination that caused the element to fail. Before installing a new element, always dig out the discolored spots in an element groove. Use a screwdriver and dental mirror. If you can't get a screwdriver into the groove, use a curved dental tool. Before installing the new elements, vacuum the grooves.
Q. Why does an element burn out suddenly rather than wear gradually?
A. Contamination with a foreign material such as kiln wash burns out an element.
The number one reason a new element burns out is a loose element connector. So read the instruction sheet that comes with replacement elements. It includes information on tightening the connectors. The instruction sheet contains a wealth of information. Read it twice before starting to work on the kiln.
Q. Does changing an element require a crimping tool?
A. No. Paragon elements use barrel connectors. You will need only a 1/4” nut driver and locking pliers to install the element connectors. (Locking pliers come in different brands. Vise-Grip is the best known.) Hold the barrel connector with the Vise-Grip pliers, and tighten the small bolt with the 1/4” nut driver.
Paragon element connectors should be tightened to 30 - 36 inch pounds. This is about 1 1/4 turns past the point of firm resistance. Suppose the head of the screw or bolt on the element connector twists off. That's okay, as long as the threads in the connector are still holding.
By the way, locking pliers are one of the most useful hand tools you can own. I have had Craftsman locking pliers since I was 19 years old and use them often. Locking pliers allow you to grip an object with tremendous power even if you have small hands.
Q. Why did smoke come out of my ceramic fiber kiln the first time I fired it?
A. The smoke that came off the kiln during the first firing is normal. It is the binders burning out of the fiber insulation.
Today a cold mist is falling in Mesquite. Every time the office door opens, a biting gust of wind swirls in. I enjoy cold weather. When I use my fireplace at home, two of my cats sit nearby to watch the fire. That is a good time to read a novel . . . or to fire a kiln.
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 firstname.lastname@example.org / www.paragonweb.com