Warren Widmayer on sat 17 dec 05
I made a mistake in programming my controller for a glaze firing last night
and the result was that instead of following the slow cooling schedule I
wanted (similar to MC6G) it essentially shut off after reaching my cone 6.
If I want to try to get the slow cooling effects, will refiring the pieces
and then cooling with the slow cooling cycle achieve this? These are mostly
glazes that are close to Ron and John's base glazes.
If I do refire, should I take it only up to 1900 (where I would normally
slow down the cooling) or should I take it up higher?
How slowly should I refire?
Any comments from people with experience in electric kiln refirings to cone
6, especially with MC6G glazes, would be appreciated. Thanks!
Warren Widmayer
Chelsea, MI
John Hesselberth on sun 18 dec 05
Hi Warren,
Take them back up to only 1900 and then do the controlled cooling. If
you take them all the way back to cone 6 you will likely end up with
overfired and runny glazes.
Regards,
John
On Dec 17, 2005, at 2:40 PM, Warren Widmayer wrote:
> If I want to try to get the slow cooling effects, will refiring the
> pieces
> and then cooling with the slow cooling cycle achieve this? These
> are mostly
> glazes that are close to Ron and John's base glazes.
Ron Roy on tue 20 dec 05
Hi Warren,
Yes - taking it back up to where you would hold will do it - but less time
because the period of time between when the glaze starts to melt and the
holding temperature will also help crystals to form.
One way of getting glazes to devitrify is to fire them again in a bisque
firing - the crystals form on the way up after the glaze starts to re melt
and on the way down till the glaze sets (becomes rigid - freezes).
There is an optimum temperature when crystals form - depending on each
glaze - finding the best temperature - where crystals form the fastest - is
possible but takes a lot of experimentation.
When refiring - on the way up - you need to stop before the crystals start
getting smaller - in other words start combining back into the glaze - if
you go past that temperature you would need to hold long enough for them to
reform.
RR
>I made a mistake in programming my controller for a glaze firing last night
>and the result was that instead of following the slow cooling schedule I
>wanted (similar to MC6G) it essentially shut off after reaching my cone 6.
>If I want to try to get the slow cooling effects, will refiring the pieces
>and then cooling with the slow cooling cycle achieve this? These are mostly
>glazes that are close to Ron and John's base glazes.
>
>If I do refire, should I take it only up to 1900 (where I would normally
>slow down the cooling) or should I take it up higher?
>
>How slowly should I refire?
>
>Any comments from people with experience in electric kiln refirings to cone
>6, especially with MC6G glazes, would be appreciated. Thanks!
>
>Warren Widmayer
>Chelsea, MI
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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