Pat K Kratzke on sun 31 aug 03
I just did a cone 6 glaze firing, and had some very discouraging results.
The top of the kiln was underfired (probably only to cone 4), but those
pots turned out the best. In the middle and the bottom, the witness
cones were the picture of perfection, but the pots were the pits. Some
had very minor bubbling in only a couple of spots, in otherwise perfect
pots. Some had a lot of bubbling, and I suspect that the glaze on those
pots was just too dang thick. I also suspect that the bisque on most of
these was underfired. I am using commercial glazes (cone 4-6), and can't
tell you much about composition, but the problems were not limited to one
glaze, and on the cooler shelves the glazes came out fine. Also, I fired
obsessively slowly, to try to make up for any underfired bisque. Didn't
appear to work. So....:
I am wondering if it would help to refire any of this. Any chance that
the bubbles would heal over? Would it help to add any glaze in those
spots first? Any tricks, other than digging a hole and chucking it all
in there for future archeologists to "discover"?
- Patti Kratzke
Kingston, WA
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Pamela Watkins on sun 31 aug 03
Hi Pat...
Seems that you've done your analysis on the firing......too thick....slow fire I don't think would make much difference. As for the rescue.... the work involved in grinding to smooth ruddy bubbles, defeats a new start. One of my first commercial glaze applications with similar results served to provide me with storage bowls for the studio and a slurry pot for the wheel; a small, intimate reminder that test fires, albeit mundane, can be productive.
Happy fires on the next round.
JaQ
Pat K Kratzke wrote:
I just did a cone 6 glaze firing, and had some very discouraging results.
The top of the kiln was underfired (probably only to cone 4), but those
pots turned out the best. In the middle and the bottom, the witness
cones were the picture of perfection, but the pots were the pits. Some
had very minor bubbling in only a couple of spots, in otherwise perfect
pots. Some had a lot of bubbling, and I suspect that the glaze on those
pots was just too dang thick. I also suspect that the bisque on most of
these was underfired. I am using commercial glazes (cone 4-6), and can't
tell you much about composition, but the problems were not limited to one
glaze, and on the cooler shelves the glazes came out fine. Also, I fired
obsessively slowly, to try to make up for any underfired bisque. Didn't
appear to work. So....:
I am wondering if it would help to refire any of this. Any chance that
the bubbles would heal over? Would it help to add any glaze in those
spots first? Any tricks, other than digging a hole and chucking it all
in there for future archeologists to "discover"?
- Patti Kratzke
Kingston, WA
________________________________________________________________
The best thing to hit the internet in years - Juno SpeedBand!
Surf the web up to FIVE TIMES FASTER!
Only $14.95/ month - visit www.juno.com to sign up today!
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Ron Roy on wed 3 sep 03
Hi Patti,
Sounds like too thick but it could also be the sisue firing - if too fast
organics can get trapped - what kind of clay you using - got any iron in
it?
Send more info kind of clay, some of the glaze recipies you are using and a
blow by blow of how you fired you bisque.
RR
>I just did a cone 6 glaze firing, and had some very discouraging results.
> The top of the kiln was underfired (probably only to cone 4), but those
>pots turned out the best. In the middle and the bottom, the witness
>cones were the picture of perfection, but the pots were the pits. Some
>had very minor bubbling in only a couple of spots, in otherwise perfect
>pots. Some had a lot of bubbling, and I suspect that the glaze on those
>pots was just too dang thick. I also suspect that the bisque on most of
>these was underfired. I am using commercial glazes (cone 4-6), and can't
>tell you much about composition, but the problems were not limited to one
>glaze, and on the cooler shelves the glazes came out fine. Also, I fired
>obsessively slowly, to try to make up for any underfired bisque. Didn't
>appear to work. So....:
>
>I am wondering if it would help to refire any of this. Any chance that
>the bubbles would heal over? Would it help to add any glaze in those
>spots first? Any tricks, other than digging a hole and chucking it all
>in there for future archeologists to "discover"?
>
>- Patti Kratzke
>Kingston, WA
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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