Jeff Tsai on sun 13 jan 02
Hi everyone,
I know I should test this myself, and I will before I do anything major, but
I was wondering if anyone knew what would happen to the copper fuming colors
on a saggar fired piece if I fired it again in a low fire glaze firing. I
know the copper will affect the areas that are glazed, but in the unglazed
areas, will the red/blue/green copper fumes burn away and leave blank clay
like the carbon where the piece is black?
thanks for any info.
-jeff
Roger Korn on sun 13 jan 02
Hi Jeff,
As with many things, it depends... If the refiring end point is below, say, cone
08, AND if the kiln atmosphere is not
oxidizing, I think the copper fuming will remain. In any event, you won't end up
with blank clay - some copper will remain
as an oxide, unless the atmosphere is very reducing AND the refiring end point is
quite high.
The above is conjecture, but I'll try the experiment next time I'm doing
saggar-fire glaze tests. Steve Branfman could probably
answer this question with more authority than I.
Roger
Jeff Tsai wrote:
> Hi everyone,
>
> I know I should test this myself, and I will before I do anything major, but
> I was wondering if anyone knew what would happen to the copper fuming colors
> on a saggar fired piece if I fired it again in a low fire glaze firing. I
> know the copper will affect the areas that are glazed, but in the unglazed
> areas, will the red/blue/green copper fumes burn away and leave blank clay
> like the carbon where the piece is black?
>
> thanks for any info.
>
> -jeff
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
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--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
L. P. Skeen on sun 13 jan 02
If you have red from copper flashing, it will probably reoxidize when fired
in what I'm assuming will be an electric kiln, and then will turn either
green or invisible, depending on how much copper got on the piece.
L
----- Original Message -----
From: "Jeff Tsai"
To:
Sent: Sunday, January 13, 2002 12:41 AM
Subject: question about refiring a saggar fired piece.
> Hi everyone,
>
> I know I should test this myself, and I will before I do anything major,
but
> I was wondering if anyone knew what would happen to the copper fuming
colors
> on a saggar fired piece if I fired it again in a low fire glaze firing. I
> know the copper will affect the areas that are glazed, but in the unglazed
> areas, will the red/blue/green copper fumes burn away and leave blank clay
> like the carbon where the piece is black?
>
> thanks for any info.
>
> -jeff
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Charlie and Linda Riggs on mon 14 jan 02
Jeff,
I've put a clear raku glaze on a saggar-fired pot and raku fired it up to cone 06.
The places that had the copper blushes turned green under the glaze.
When I've re-bisqued saggar-fired pots to 08, usually the copper is burned out and
I have a "clean slate" again. Occasionally though, I'm surprised by a residue of
red/orange color that remains. That is usually the color that comes from the iron
in the steel wool The most common occurance, though, is that the copper and iron
fuming disappears.
Linda
> ----- Original Message -----
> From: "Jeff Tsai"
> To:
> Sent: Sunday, January 13, 2002 12:41 AM
> Subject: question about refiring a saggar fired piece.
>
> > Hi everyone,
> >
> > I know I should test this myself, and I will before I do anything major,
> but
> > I was wondering if anyone knew what would happen to the copper fuming
> colors
> > on a saggar fired piece if I fired it again in a low fire glaze firing. I
> > know the copper will affect the areas that are glazed, but in the unglazed
> > areas, will the red/blue/green copper fumes burn away and leave blank clay
> > like the carbon where the piece is black?
> >
> > thanks for any info.
> >
> > -jeff
> >
> >
> ____________________________________________________________________________
> __
> > Send postings to clayart@lsv.ceramics.org
> >
> > You may look at the archives for the list or change your subscription
> > settings from http://www.ceramics.org/clayart/
> >
> > Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
> >
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
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