Pottery/Duncan EA 1020 Kiln Manual Firing Schedule
I have a Duncan ea 1020 kiln which I have recently acquired and have not yet fired. I saw a question to from Alice back in 2011 who also had questions about firing this model of kiln, all the dials and switches described by Alice are exactly like mine and I am wondering if you can advise me similarly. I want to fire this kiln manually so that I can cool down manually which is when I want my glazes to really develop depth. Is it possible to fire this kiln manually without using the cone sitter which I understand will turn the kiln off when it has reached temperature depending on which cone is being used? Also, is it possible to soak at certain temperatures, at the top and also during cooling down? I have never used an electric kiln before, used to manually controlling a gas kiln, as much as one can control a gas kiln, that is! Thank you.
Thank you for your recent question. Yes, you can fire the kiln without the kiln sitter. You will need bring the arm of the sitter up and then push in the plunger to start the kiln. Let the arm come down slowly so that it doesn't trip the kiln off.
As for soaking, you will be limited to the way you soak if you are not using a digital pyrometer to help you determine the temperature you are currently at and if you are holding at the temperature you need for the soak. This kiln fires faster than a normal kiln as it was designed to be an energy saver kiln. Therefore, you will need to control the temperature of the kiln using a digital pyrometer and adjust the control knob, the one with off, overglaze, ceramic and high fire on the markings, to raise, maintain or lower the temperature of the kiln.
I have included a manual for your kiln below:
Firing an electric kiln is very much different than firing a gas kiln. Gas kilns rely on oxygen to control the amount of heat in the kiln and because of the amount of air flowing into and out of the kiln, it is harder to control the temperature of the kiln. For potters, it takes many years of working with the kiln to discover how the kiln reacts to gas flow and damper control to achieve a basic knowledge of the kilns temperament. And even then, changes in outside temperature, the packing of the kiln and ceramic vapor can change the reaction the kiln gives during firing.
An electric kiln is less likely to give you any problems with temperature control once you learn the approximation of the temperature you are trying to reach or hold using the control knob. The best way to find out how the kiln fires is to fire it with test pieces and using the digital pyrometer, stay with the kiln on the first couple of firings, adjusting the kiln according to the readings on the pyrometer.
You will want to use a kiln schedule sheet to record the firings so that you will have a good record to follow. I have included two record sheets below that you can use to experiment with the kiln. It is important that you use these sheets to help you determine the kiln temperament and to determine a firing schedule for the type of firing you wish to do.
I suggest during your test firings that you use a pyrometric cone pack inside the kiln to also help you determine where the kiln temperature is during firing. You you will use three cones in the pack, one cone lower, the maturing temperature cone and one cone higher to help you determine when you need to hold, when the kiln has reached maturing temperature and to prevent over firing. If you choose not to use the cone pack, you should use the following chart to determine the maturing temperatures of the kiln you are needing to reach and what temperature you will need to be at for the soak as well as what temperature you need to lower to for a cooling soak.
When you are ready to fire the kiln, load the kiln, close the lid and leave the peep hole cones out to allow escape of excess chemical waters. Turn the timer to at least 10 to assure the kiln will not turn off during your firing and allow you to have control of the kiln. Set the sitter by raising the arm to the top and pushing in the plunger. Carefully lower the arm so that the plunger remains in the pressed position. Place the digital pyrometer in position and turn the control knob to high fire. After two hours, place the peep hole cones into the kiln. Once the digital pyrometer shows the temperature where you want to begin controlling the kiln, use the control knob to lower the kiln temperature to the soak temperature by turning it towards the ceramic position. When the digital pyrometer registers the temperature you want to soak at, keep the control knob at the current position for the soak period you desire. Continue this process for the cooling soak by lowering the temperature using the control knob by turning it towards overglaze until your cooling temperature soak is reached. Once again, hold at that temperature for the desired amount of time for the soak, then turn the kiln off by turning the control knob off and forcing the sitter to turn off by raising the arm and letting it drop. The plunger will pop outward and turn the kiln off. Turn the timer to zero and let the kiln cool normally.
Be sure and record every step you take during the firing so that you can repeat the firing process in the future.
I hope this assists you in firing your kiln. If you have further questions, please feel free to contact me any time. I am always at your service. Much luck to you.
Ms. Ti Phillips
Earth Stoke 'N Fire Pottery Studio and Artist Retreat