Mary White on wed 28 dec 05
I set my kiln to bisque overnight and when I went to check it in the
morning, when it should have still had a couple of hours to go, the
controllor showed Error and it had turned itself off. The temperature
was reading 175 F and the pots are bisqued in that they are strong
and they ring when you touch them but I have no idea what temperature
they got to since I foolishly didn't put a cone pack in the kiln. I
normally bisque to ^04. They're made of ^5 B-mix and my only clue is
that they're a very pale pink-tan colour instead of the normal white.
Should I go ahead and glaze them, re-bisque them or just chuck them?
Mary
on the Sunshine Coast, BC, Canada
Hank Murrow on wed 28 dec 05
Dear Mary;
My best guess is cone 1. May have to add Karo syrup to your glaze, or
heat the bisque up to provide absorbency.
Cheers, Hank
On Dec 28, 2005, at 4:02 PM, Mary White wrote:
> I set my kiln to bisque overnight and when I went to check it in the
> morning, when it should have still had a couple of hours to go, the
> controllor showed Error and it had turned itself off. The temperature
> was reading 175 F and the pots are bisqued in that they are strong
> and they ring when you touch them but I have no idea what temperature
> they got to since I foolishly didn't put a cone pack in the kiln. I
> normally bisque to ^04. They're made of ^5 B-mix and my only clue is
> that they're a very pale pink-tan colour instead of the normal white.
>
www.murrow.biz/hank
Mary White on wed 28 dec 05
Hank, you're a wonder--
Are you kidding about the Karo syrup? And what do you mean by heating
the bisque up. You're a guy I always trust because you know what
you're talking about but unfortunately I don't.
Mary
on the Sunshine Coast, BC, Canada
>Dear Mary;
>
>My best guess is cone 1. May have to add Karo syrup to your glaze, or
>heat the bisque up to provide absorbency.
>
>Cheers, Hank
>
>On Dec 28, 2005, at 4:02 PM, Mary White wrote:
>
>>I set my kiln to bisque overnight and when I went to check it in the
>>morning, when it should have still had a couple of hours to go, the
>>controllor showed Error and it had turned itself off. The temperature
>>was reading 175 F and the pots are bisqued in that they are strong
>>and they ring when you touch them but I have no idea what temperature
>>they got to since I foolishly didn't put a cone pack in the kiln. I
>>normally bisque to ^04. They're made of ^5 B-mix and my only clue is
>>that they're a very pale pink-tan colour instead of the normal white.
>>
>www.murrow.biz/hank
>
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dannon rhudy on thu 29 dec 05
Mary said:
> I set my kiln to bisque overnight... turned itself off....> Should I go
ahead and glaze them, re-bisque them or just chuck them?......
You can re-bisque if you like, though it is not
strictly necessary. There may be some things
still in the clay that would have fired out if they'd
reached normal bisque. So - fire your glaze
fire a bit slowly up to your normal bisque temp,
then follow your usual schedule. The slower
firing should enable any impurities to burn out
before the glaze seals the clay. You should avoid
pinholing and blistering, in that way. No reason to
throw them out.
regards
Dannon Rhudy
Kathi LeSueur on thu 29 dec 05
Hank Murrow wrote:
> Dear Mary;
>
> My best guess is cone 1. May have to add Karo syrup to your glaze, or
> heat the bisque up to provide absorbency.
>
> Cheers, Hank
> On Dec 28, 2005, at 4:02 PM, Mary White wrote:
>
>> I set my kiln to bisque overnight and when I went to check it in the
>> morning, when it should have still had a couple of hours to go, the
>> controllor showed Error..... I have no idea what temperature
>> ..... my only clue is that they're a very pale pink-tan colour
>> instead of the normal white.
>>
My experience would cause me to disagree with this conclusion. I've
found that white firing clays tend to pink-tan when underbisqued. But,
the easiest test is to take one piece and dip it in a glaze. If it
absorbs fast, it's underfired. If it absorbs slowly, then it's
overfired. I'd still glaze the whole batch. Just adjust how long it's
in the glaze depending on whether it seems over or underfired.
Kathi
William & Susan Schran User on thu 29 dec 05
On 12/28/05 7:02 PM, "Mary White" wrote:
> I set my kiln to bisque overnight and when I went to check it in the
> morning, when it should have still had a couple of hours to go, the
> controllor showed Error and it had turned itself off.
>....the pots are bisqued in that they are strong
>and they ring when you touch them but I have no idea what temperature
>they got to since I foolishly didn't put a cone pack in the kiln.
>Should I go ahead and glaze them, re-bisque them or just chuck them?
Your pots have been fired high enough that you could glaze them as they are,
but if you normally fire to ^04 and have your glazes to a specific
consistency and you have a certain way of glaze application on ^04 bisque,
then you may want to consider re-firing.
As you've found out, having a cone pack in every firing, even if it's not
visible from a spy hole, is critical for a record of the firing, even if the
kiln has a Kilnsitter AND thermocouple feeding information to a programmable
controller.
Boy, firing a kiln overnight without hourly checks, IMHO, a pretty scary
thing to do.
-- William "Bill" Schran
Fredericksburg, Virginia
wschran@cox.net
wschran@nvcc.edu
Hank Murrow on thu 29 dec 05
On Dec 28, 2005, at 5:02 PM, Hank Murrow wrote:
> Dear Mary;
>
> My best guess is cone 1. May have to add Karo syrup to your glaze, or
> heat the bisque up to provide absorbency.
Sorry Mary;
Having just had a bisque overfire due to a stuck cone, I lazily read
your post as overfiring. What I suggested would only apply to pots that
were overfired in the bisque. You can just re-fire the pots to your
usual cone.
Cheers and an apology, Hank
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