Sandy Cryer on fri 14 mar 03
Has anyone used B-3 Black clay from Laguna. I had used B-3 Brown without
prob, so thought I would try this black clay. It threw ok, fired ok, but a
blue glaze we use at out club spits off of it during the cone 6 elec. firing.
This happened on several pieces thrown by different potters. It didn't just
spit off, it flew off, plus where it overlapped other glazes, what was left
on the pot after spitting off, crawled away from the other glaze in a stripe
equivilent to the overlap. Very strange. The glaze formula is listed below,
a nice bright blue, anyone have any ideas?
The firing schedule is the one in Mastering Cone 6 Glazes
Cone 6, Electric
Saphire Blue
Custer feldspar 25.8
Gerstley borate 20.4 (this is prob Laguna Borate as they mix it for
us now)
Whiting 3.8
Silica 27.1
EPK 1.6
Talc 2.8
Nepheline syenite 13.6
Zinc oxide 4.8
**
Copper carbonate 3.0
Cobalt carbonate 1.0
dalecochoy on fri 14 mar 03
----- Original Message -----
From: "Sandy Cryer"
Subject: B-3 Black clay from Laguna
> Has anyone used B-3 Black clay from Laguna. I had used B-3 Brown without
> prob, so thought I would try this black clay. It threw ok, fired ok, but
a
> blue glaze we use at out club spits off of it during the cone 6 elec.
firing.
> This happened on several pieces thrown by different potters. It didn't
just
> spit off,
Yes, I USED to use the B3 BROWN ( I would consider it black though) a few
years ago but found that it very often did just that, Note: It was ALWAYS on
a sharp edge like the rim and then sometimes it also extendeed down the
sides. Also, once high fired I could not successfully reglaze and refire .
BTW, It also was not good for slab building...too many seam cracks and feet
popping off. I gave up on it. I threw out a lot of pots from that clay.
It did make a nice unglazed, wheel thrown pot however
Regards,
Dale Cochoy
Debbie on fri 14 mar 03
I did a ^6 talc set on a B-3 Brown tile and the glazes bubbled and cratered
magnificently!
You can see a picture of it posted at
http://www.lightonecandle.com/tn_currieengle.html
Debbie
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