Chris Schafale on mon 8 feb 99
Hi Ron and Clayart folk,
Just unloaded my tests of your second cone 6 black (see recipe
below). This time the tests were on Laguna 70, a darkish brown
stoneware. Fired to cone 6, perfect, just-touching-the-shelf cone
bend with a 30 minute hold at top temp. Rate of temperature rise
from 700 C was 100C per hour up to 1050, and 60 C per hour from 1050
to finish.
The test tiles are in the freezer now -- I'll let you know about any
results there as soon as I know, but for now I wanted to tell you --
it looks like a winner! Nice, glossy surface, quite black, breaking
brown over edges/where thin/if the light catches it right. No
crawling in sight, no running, no obvious crazing. Looks great!
A question: do you have suggestions about how to detect crazing on
dark colored and/or matt glazes? Even with a 30x monoscope, I have
trouble seeing craze lines on dark glazes, even when I'm pretty sure
they're there.
Thanks!
Chris Schafale
> So here is the next one - melted more with a bit less iron to cut down the
> crystalization on the surface. I've added some betonite to stop the
> crawling. If that does not work we need to switch to ball clay - Let me
> know what kinds you have or can get if there is any sign of crawling on
> this one.
>
> RR c6 black #2
> -----------------
> F4 SPAR................21.00
> WHITING................6.00
> TALC........................3.00
> F3134....................26.00
> EPK........................17.00
> SILICA...................27.00
> BENTONITE...........2.00
> RED IRON OX........9.00
> coblt carb.......... 1.00
> ----------
> Total.....................112.00
> FORMULA & ANALYSIS
> ------------------
> *CaO........ .46 8.71%
> MnO2....... .00 .00%
> *MgO........ .07 .94%
> *K2O........ .03 1.03%
> *Na2O....... .19 3.99%
> Fe2O3...... .16 8.76%
> TIO2....... .00 .05%
> *B2O3....... .24 5.70%
> AL2O3...... .30 10.38%
> SiO2....... 3.00 60.43%
> P2O5....... .00 .02%
>
> RATIO 9.90
> EXPAN 451.52
> WEIGHT 298.03
>
Light One Candle Pottery
Fuquay-Varina, NC
candle@nuteknet.com
lpskeen on mon 8 feb 99
Chris Schafale wrote:
> A question: do you have suggestions about how to detect crazing on
> dark colored and/or matt glazes? Even with a 30x monoscope, I have
> trouble seeing craze lines on dark glazes, even when I'm pretty sure
> they're there.
Chris,
I'd try rubbing chalk (white, of course), baby powder, or white ink into
the glaze.
--
Lisa Skeen ICQ# 15554910
Living Tree Pottery & Soaps http://www.uncg.edu/~lpskeen
FAILURE IS NOT AN OPTION!!! It comes bundled with the software.
The Bill of Rights - (void where prohibited by law)
Brian Crocker on tue 9 feb 99
G'day Chris,
To detect crazing on dark glazes,, use a white "correction pen" on a cooled
test tile
and quickly rub it in then have a look at it with a 4x magnifier ..
Kind regards Brian C..
At 01:35 PM2:10: 8/02/99 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Ron and Clayart folk,
>
>Just unloaded my tests of your second cone 6 black (see recipe
>below). This time the tests were on Laguna 70, a darkish brown
>stoneware. Fired to cone 6, perfect, just-touching-the-shelf cone
>bend with a 30 minute hold at top temp. Rate of temperature rise
>from 700 C was 100C per hour up to 1050, and 60 C per hour from 1050
>to finish.
>
> The test tiles are in the freezer now -- I'll let you know about any
>results there as soon as I know, but for now I wanted to tell you --
>it looks like a winner! Nice, glossy surface, quite black, breaking
>brown over edges/where thin/if the light catches it right. No
>crawling in sight, no running, no obvious crazing. Looks great!
>
>A question: do you have suggestions about how to detect crazing on
>dark colored and/or matt glazes? Even with a 30x monoscope, I have
>trouble seeing craze lines on dark glazes, even when I'm pretty sure
>they're there.
>
>Thanks!
>
>Chris Schafale
>
>
>> So here is the next one - melted more with a bit less iron to cut down the
>> crystalization on the surface. I've added some betonite to stop the
>> crawling. If that does not work we need to switch to ball clay - Let me
>> know what kinds you have or can get if there is any sign of crawling on
>> this one.
>>
>> RR c6 black #2
>> -----------------
>> F4 SPAR................21.00
>> WHITING................6.00
>> TALC........................3.00
>> F3134....................26.00
>> EPK........................17.00
>> SILICA...................27.00
>> BENTONITE...........2.00
>> RED IRON OX........9.00
>> coblt carb.......... 1.00
>> ----------
>> Total.....................112.00
>> FORMULA & ANALYSIS
>> ------------------
>> *CaO........ .46 8.71%
>> MnO2....... .00 .00%
>> *MgO........ .07 .94%
>> *K2O........ .03 1.03%
>> *Na2O....... .19 3.99%
>> Fe2O3...... .16 8.76%
>> TIO2....... .00 .05%
>> *B2O3....... .24 5.70%
>> AL2O3...... .30 10.38%
>> SiO2....... 3.00 60.43%
>> P2O5....... .00 .02%
>>
>> RATIO 9.90
>> EXPAN 451.52
>> WEIGHT 298.03
>>
>Light One Candle Pottery
>Fuquay-Varina, NC
>candle@nuteknet.com
>
>
Brian Crocker
4 Erica Street,
Tea Tree Gully 5091,
South Australia,
Australia. {e.mail} crocker@dove.com.au
"Never loose sight of the bigger picture,"
"Never loose sight of what you set out to achieve." NAB.
" I would like one Life to Learn and another to Use It " A.W.Kester. My Grandpa.
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