iandol on thu 29 nov 01
Dear Cindy Romanski,
I am not sure what other opinions you will get but I think this is very =
fast for that cone value.
I would anticipate to go to cone 10 in about fifteen hours and if I went =
faster I would expect the pyrometer temperature reading to go well above =
the recommended reading for Orton Cone 10. This will bring you into a =
situation where the clay becomes fluid even though it does not get =
sufficient heat to create transparency.
The technology behind this is that ascertained by Hermann Segar who =
realised that many ceramic substances and mixtures become fluid before =
they fully fuse and hence become unstable and loose their physical =
strength. This is why Orton and other cones lean over. Sufficient liquid =
is generated from the fluxes to allow everything else to slide under the =
effects of gravity.
My suggestion is that you ramp your controller for heating to the =
recommended rate for the cones you are using. You can cross check this =
with your clay supplier if there are any doubts in your mind.
I fire my clays slowly. My cones drop at relatively low Pyrometer =
readings. I do not have any warping problems.
Best regards,
Ivor Lewis. Redhill, South Australia.
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