Karen Shapiro on thu 28 jan 99
Hi Clayarters,
I am looking for some help with finding a clear raku glaze which won't
"smudge" underglaze designs when fired. I do a lot of detail work which I
want to be sharp after rakued. I have been using: Gerstely borate 70,
Neph.Sye 30, which is a very nice crackle gloss glaze, but is too "soft" in
that my details (which take me hours to apply!) can be lost. There are SO
many formulae that I could be testing for years!
Appreciate any help,
Karen in Sonoma
doug shea on fri 29 jan 99
Karen Shapiro wrote:
>
> ----------------------------Original message----------------------------
> Hi Clayarters,
>
> I am looking for some help with finding a clear raku glaze which won't
> "smudge" underglaze designs when fired. I do a lot of detail work which I
> want to be sharp after rakued. I have been using: Gerstely borate 70,
> Neph.Sye 30, which is a very nice crackle gloss glaze, but is too "soft" in
> that my details (which take me hours to apply!) can be lost. There are SO
> many formulae that I could be testing for years!
> Appreciate any help,
> Karen in Sonoma
Karen,
Do you bisque after applying your underglaze decoration, but
before glazing? If not, that could account for the "smudging." Since
you're rakuing, which fires to about the same temp as most people
bisque, the underglazes shouldn't go anywhere when re-fired in the raku
kiln. If you don't want the extra step of refiring to set the
undergalzes, you could just paint on the greenware.
If you already are doing that, you might want to try changing
the proportions in the recipe.
50 Gerst. Borate
50 Neph Sy
can give you large dramatic crackle (depending on the thickness of your
pot, shape, etc). It also tends to mature at a little lower temp, but
has great staying power. I regularly fire some other glazes to ^04 and
this crackle hangs on the pot like a champ.
Up to
80 GB to 20 Neph Sy
This tends to give smaller crackle and probably isn't much
different from yours.
Try varying proportions & see if it makes a difference.
Jim Shea
Lana Reeves on fri 29 jan 99
Karen-- I often use underglaze on pieces that will be fired in differnt
ways, including raku. Some underglaze colors "sag" or spread more than
others. I've found the best way to be safe is to do a second bisque for the
underglazes. It doesn't have to be very hot- ^12 or so- just enough to
"set" the colors.
Lana in Somerville, MA
kilnkat@javanet.com
-----Original Message-----
From: Karen Shapiro
To: CLAYART@LSV.UKY.EDU
Date: Thursday, January 28, 1999 7:40 AM
Subject: seeking clear raku glaze
>----------------------------Original message----------------------------
>Hi Clayarters,
>
>I am looking for some help with finding a clear raku glaze which won't
>"smudge" underglaze designs when fired. I do a lot of detail work which I
>want to be sharp after rakued. I have been using: Gerstely borate 70,
>Neph.Sye 30, which is a very nice crackle gloss glaze, but is too "soft"
in
>that my details (which take me hours to apply!) can be lost. There are SO
>many formulae that I could be testing for years!
>Appreciate any help,
>Karen in Sonoma
>
Karen Broderick on fri 29 jan 99
Karen,
I have used Robert Piepehburg's white crackle over underglazes and
added
mason stains to it and have had wonderful results. Good Luck!
Karen
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