Orton Cones, number 05, box of 50

Orton cones bend at different temperatures depending on the heating rate in the last hour of firing. It takes about 15 to 25 minutes for a cone to bend fully, slowly at first but quickly once they are bent past half way. They will also bend if soaked, and half an hour of soaking may bend a cone of a higher temperature.
Cones can be used to determine if your kiln is firing hotter in certain places in your kiln.
Stand the cones in a purpose made plaque, or a pat of clay (but do allow the pat of clay to dry out before placing it in the kiln!).
05 cones bending chart -.
Heating rate in°C per hour -.
60°C per hour - bend at 1030°C.
100°C per hour - bend at 1038°C.
150°C per hour - bend at 1046°C