Carol Tripp on thu 4 mar 04
Hi Ron,
I can see you; hands on hips, shaking your head and wondering why oh why
does this woman NEVER listen to me?! Actually, it was you who spilled the
beans about refiring iron reds in the bisque fire. I know it was ;-) I
took that infomation in and acted on it. Since then, you have told me
several times to just fire down more slowly so I can skip the extra firing.
And you know something? Some iron reds just have to have the second firing.
Berry Rust never does, Persimmon always does and my own personal Iron Red
Melange needs a second firing when on MCS but not on Smooth Stone or
Mid-Red. One never gets bored when working with clay...
You are a prince though, even if you do change your mind. And I think I do
fire down pretty slowly; top out at 1194C with a soak, then cool to 1037C
and go at 50C/hour until shut down at 750C. I get ^6 top to bottom most of
the time. And I bisque to ^05. Why ^05? A few years ago, I aimed for ^04,
hit ^05 and stayed with it.
Best regards,
Carol
Dubai, UAE
Ron Roy wrote:
>The same thing can be done by slow cooling at the right temperature.
>
>What the refiring to a bisque temperature does to some glazes - is give
>extra time for those crystals to form - on the way up and on the way down.
>
>Crystals form during that part of the firing while the glaze is still soft
>but not actively melting. It's hard to say what temperature that is because
>it is different for each glaze.
>
>If you assume the glaze is probably still soft down to 600 C - and time how
>long it takes for your bisque firing to get up to temperature from 600C and
>them back down to 600 then you have some idea how long to slow your cooling
>down during the glaze firing. the longer the cooling during that time the
>more crystals will develope - up to a point.
>
>What you don't want to do is start remelting the crystals that have already
>formed when refiring - I would guess a low bisque (06) might work better
>than one at cone 04 for many cone 6 glazes by the way - especially those
>high in boron.
>
>RR
>
> >Hi all you Iron Red at ^6 fans,
> >I find that putting these iron red pots into a bisque fire after the
>glaze
> >firing brings out the red. They are all brown for me at ^6 but become
>deep
> >crystallish rich red at ^05-^06. Ron Roy says this is called "striking"
>-
> >and yes, that just about describes them.
> >Best regards,
> >Carol
> >Dubai, UAE
>
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Ron Roy on sat 6 mar 04
Hi Carol,
No no - not at all. I was not so much talking to you as to everyone else.
Just my way of wanting everyone to understand why it works.
To get the same effect as a refire you would have to claculate the amount
of time the crystals get to form using the refire method - and make sure
the slow cool was the same amount of time.
Count the hours on the way up in the bisque from 700C and on the way down
to 700C and add in the original slow cool period - then slow cool the same
amount of time. The results should be same. The crystals don't care when it
happens - as long as you don't remelt them and they get the same amount of
time to grow.
RR
>I can see you; hands on hips, shaking your head and wondering why oh why
>does this woman NEVER listen to me?! Actually, it was you who spilled the
>beans about refiring iron reds in the bisque fire. I know it was ;-) I
>took that infomation in and acted on it. Since then, you have told me
>several times to just fire down more slowly so I can skip the extra firing.
>And you know something? Some iron reds just have to have the second firing.
> Berry Rust never does, Persimmon always does and my own personal Iron Red
>Melange needs a second firing when on MCS but not on Smooth Stone or
>Mid-Red. One never gets bored when working with clay...
>
>You are a prince though, even if you do change your mind. And I think I do
>fire down pretty slowly; top out at 1194C with a soak, then cool to 1037C
>and go at 50C/hour until shut down at 750C. I get ^6 top to bottom most of
>the time. And I bisque to ^05. Why ^05? A few years ago, I aimed for ^04,
>hit ^05 and stayed with it.
>Best regards,
>Carol
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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