Carol Baker on sun 31 oct 99
Hi friends,
It's Carol in Arizona with the B-mix ^5, again. No crazing this time,
just strange marks on the sides of my large platters. They are a brown/gray
and in areas on two sides. They look like a flame mark on paper. I'm firing
to ^6 in a Skutt 1231 with a controller. The self-supporting cones are
firing to 6 on all shelves, consistently. The platters are about 6 inches
from the elements, and there are no other pieces on the shelf. Do elements
have hot spots? Should I protect the edges by putting other ware around
them? Should I not be firing the B-mix to ^6. I take it to six to be sure
it is vitrified, because I had crazing before This is only the second time
I've fired this new kiln. I did not have this problem in my smaller kiln.
Could the controller be doing such a good job of hitting ^6 that now a 6 in
the 1231 is too high?
Right now I don't have much time to experiment and test. These pieces
were for a charity auction this Friday. I've got one more firing this week.
Can you save me in time? I'm still learning from you all - every day!
Thanks so much for sharing. The glaze follows.
Carol Baker, Scottsdale, Arizona
D. Woods ^6 clear
G-200 feldspar 30
Dolomite 7
Whiting 16
EPK 17
Silica 30
100
Cindy Strnad, Earthen Vessels Pottery on mon 1 nov 99
Carol,
^6 in a small kiln with a sitter, using mini cones or bars and ^6 in a large
kiln with a thermocouple and controller are two entirely different animals.
The usual ritual is to use ^7 mini cones/bars if you want to reach a true
^6. Even so, I think the actual firing falls a little bit below what you
would get if you used full-sized cones.
If I were in your position, I'd fire the remaining pieces in the small kiln,
since it's important to get them done on time. If the small kiln is no
longer available, I'd set the controller to fire to ^5 in the large kiln.
It'll take a while to get used to the new kiln, no matter how good a kiln it
is. Sounds like yours is an excellent piece of equipment. You just have to
get acquainted.
Best wishes,
Cindy Strnad
Earthen Vessels Pottery
Custer, SD
Carol Baker on tue 2 nov 99
Thanks, Cindy, for the help. I was pondering along that same line. I can't
fire in the small kiln because my new pieces are too big. Oh, what Clayart
has done to me. Big shapes, computers, confidence (well, a little more,
anyway). Next I guess I'll invest in software. Thanks again, Carol
gambaru on tue 2 nov 99
I suspect that what you are seeing is carbon. The solution is in your
bisque firing. Slow down during the time when you are burning off carbon.
MB
----- Original Message -----
From: Carol Baker
To:
Sent: Sunday, October 31, 1999 11:31 PM
Subject: Help? Burn marks in oxidation
> ----------------------------Original message----------------------------
> Hi friends,
> It's Carol in Arizona with the B-mix ^5, again. No crazing this time,
> just strange marks on the sides of my large platters. They are a
brown/gray
> and in areas on two sides. They look like a flame mark on paper. I'm
firing
> to ^6 in a Skutt 1231 with a controller. The self-supporting cones are
> firing to 6 on all shelves, consistently. The platters are about 6 inches
> from the elements, and there are no other pieces on the shelf. Do
elements
> have hot spots? Should I protect the edges by putting other ware around
> them? Should I not be firing the B-mix to ^6. I take it to six to be
sure
> it is vitrified, because I had crazing before This is only the second
time
> I've fired this new kiln. I did not have this problem in my smaller
kiln.
> Could the controller be doing such a good job of hitting ^6 that now a 6
in
> the 1231 is too high?
> Right now I don't have much time to experiment and test. These pieces
> were for a charity auction this Friday. I've got one more firing this
week.
> Can you save me in time? I'm still learning from you all - every day!
> Thanks so much for sharing. The glaze follows.
>
> Carol Baker, Scottsdale, Arizona
>
> D. Woods ^6 clear
> G-200 feldspar 30
> Dolomite 7
> Whiting 16
> EPK 17
> Silica 30
> 100
>
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