kathleen chase on mon 2 oct 00
Hi- I am hoping some one can help with this quandary...
My terrific clear glaze has developed small white grains in it. =
Sometimes they are visible before firing (and I try to scrape them off), =
other times not until the pieces are fired. They appear to be tiny =
particles of an unmelted white substance. I have tried changing to a new =
bag of Wollastonite, a new bag of frit, and milling in the ball mill. =
This glaze problem giving my dremel quite a work out, and resulting in a =
lot more seconds and bad tempers all around. It is basically the =
20/20/20/20/20 formula tweaked a little for crazing on ^6 white clay and =
worked great for a while...
6A Clear
Feldspar - 20
Wollastonite - 15
Flint - 20
EPK (Kaolin) - 25
Frit 3134 - 20
Gum - 5
Thanks!-Kathy Chase kmchase@capecod.net=20
Cindy Strnad on mon 2 oct 00
Kathy,
The thing that surprises me is not that you have white specks now, but that
you didn't have them before. I've tried making wollastonite glazes without
sieving, and I'm pretty sure there's no way you're going to get this glaze
smooth without sieving it.
I sieve once, from my original container to a large tub, wash out my
original container, then sieve the glaze back into it. I use an 80 mesh
sieve, which should be available from your favorite supplier. If I'm going
to spray, I use a 220 mesh--'cause that's what I've got. You might not need
to go quite that fine.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
www.earthenvesselssd.com
Michael Banks on tue 3 oct 00
You don't mention Kathleen whether you sieve the glaze -or to which mesh
size. Wollastonite is a well-known contributor of small lumps which have to
be sieved out. If you can see the lumps prior to firing, you have to sieve
finer (try 100 mesh).
Michael,
in NZ
----- Original Message -----
kathleen chase wrote:
Hi- I am hoping some one can help with this quandary...
My terrific clear glaze has developed small white grains in it. Sometimes
they are visible before firing (and I try to scrape them off), other times
not until the pieces are fired. They appear to be tiny particles of an
unmelted white substance. I have tried changing to a new bag of
Wollastonite, a new bag of frit, and milling in the ball mill. This glaze
problem giving my dremel quite a work out, and resulting in a lot more
seconds and bad tempers all around. It is basically the 20/20/20/20/20
formula tweaked a little for crazing on ^6 white clay and worked great for a
while...
6A Clear
Feldspar - 20
Wollastonite - 15
Flint - 20
EPK (Kaolin) - 25
Frit 3134 - 20
Gum - 5
Mary Ella Yamashita on tue 3 oct 00
Kathy,
I use a similar glaze; rescreening it seems to help me when I have this
problem (I think it may be caused by wollastonite settling out a bit, but I
am not sure). Good luck--
Mary Ella
>Date: Mon, 2 Oct 2000 11:17:08 -0400
>From: kathleen chase
>Subject: problem with glaze???
>
>Hi- I am hoping some one can help with this quandary...
>My terrific clear glaze has developed small white grains in it. Sometimes
they are visible before firing (and I try to scrape them off), other times
not until the pieces are fired. They appear to be tiny particles of an
unmelted white substance. I have tried changing to a new bag of
Wollastonite, a new bag of frit, and milling in the ball mill. This glaze
problem giving my dremel quite a work out, and resulting in a lot more
seconds and bad tempers all around. It is basically the 20/20/20/20/20
formula tweaked a little for crazing on ^6 white clay and worked great for
a while...
>6A Clear
>Feldspar - 20
>Wollastonite - 15
>Flint - 20
>EPK (Kaolin) - 25
>Frit 3134 - 20
>Gum - 5
>
| |
|
