Arnold Howard on mon 5 may 03
On 10-28-96, Orton revised some of their cone temperatures. Most of the
changes were minor. Example: 05 became 3 deg. F. cooler.
Cones 6 & 7 had the biggest changes in temperature:
Cone 6 before 10-28-96: 2199
Cone 6 after 10-28-96: 2232
Cone 7 before 10-28-96: 2228
Cone 7 after 10-28-96: 2262
These figures are for self-supporting cones with temperature increase of
108 deg. F. during the last hour.
At the time, the temperature changes in cones caused a lot of confusion,
because controllers were calibrated with the older cone temperatures.
Sincerely,
Arnold Howard
Paragon Industries, L.P.
www.paragonweb.com
From: Bob Nicholson
> >ok, what's the deal with orton changing the temperature
> >of cone 6? has anyone heard of this?
>
> It's important to remember that cones are not the same as
> temperature. Cones measure heat-work.
>
> The final temperature for a firing to a specific cone is related
> to the rate of heat rise. For example, the Orton chart shows
> three values for Cone 6, based on the rise rate per hour:
>
> RISE FINAL
>
> 27 2165
> 108 2232
> 270 2269
>
>
> Also remember that the figures for self-supporting cones,
> large cones, and small cones are slightly different.
>
> To my knowledge, Orton has not made any changes to the
> cone 6 values in recent year, but depending on which
> figure is being quoted for which cone, you may hear
> different temperatures.
>
> As others have pointed out, glazing is a somewhat
> inexact science; whatever the temperature numbers
> you read from the chart, you need to learn what works
> with your glazes and your kiln.
>
> Hope this helps clarify things a little.
>
> - Bob Nicholson
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