Why Use Them?
On modern electric kilns you can set the time and temperature for a firing. But not all kilns will do what you have programmed it to do. For instance, low powered kilns will slow significantly toward a high temperature, modern insulations will hold onto temperatures prolonging the cool down, and elements nearing their end of life can struggle giving you varying results. Cones can help you understand what your kiln is really doing. They are designed to melt when the correct time and temperature has been met, this tells you ‘Heat-work’. So, if you are getting to know your kiln for the first time, or you suspect a problem, test with cones.
How To Use Them
There are different rates in climb in temperature, Orton uses 15°c, 60°c and 150°c degrees and hour. Orton themselves say, think of them as slow, medium and fast. These climb rates refer to the last 100°c to the top temperature you are trying to reach. When the correct ‘heat-work’ has been met the cone will bend, to a calculated angle. You may notice that a slow firing to a lower temperature can equal a faster firing to a higher temperature, both achieving the same heat-work.
Referring To The Chart
We sell ‘self-supporting cones’ so you need to refer to the chart below.
You will notice the cones are identified with numbers, from 022 to 14. Note the 0 is important, for instance 06 on one range is 1013 degrees, while cone 6 is 1243 degrees.
Traditionally, 3 cones are used, 1 x of a lower cone, 1 x target cone, 1 x higher cone (guard, target, guide). This will give you more information as to how much heat-work your wares had.
You can place them in a row, and they should not be close to the elements. In large kilns you might want to put more than one set in several places.
Orton Ceramics have useful videos explaining how the cones can be interpreted, with other common questions explained that you can view here.
If you have any further questions, please call 01934 863040 and ask for our Technical Co-Ordinator.
