Ababi on mon 30 jul 01
The tests where made on tests tiles made out of groged raku claybody
covered with slip made out of Raku
porcelain follow V.C
which was
40 EPK
20 ball clay
18 talc
12 alumina
10 molochite
and
40 EPK
+defloculant
20 German slipcasting red clay called G.R.T.
18 talc
12 alumina
10 molochite
+defloculant
One test was with slip without defloculant, trying to get it more water
in the slip
and more opened. I did fire the last one yet.
I made also two pieces out of claybody,
40 EPK
20 German slipcasting red clay called G.R.T.
18 talc
12 alumina
10 molochite.
+ bentonite
It passed the firing peacefully.
But the pinkness mostly was not shown, not enough red, nothing special.
It looked that the slips, that applied on the greenware (tiles)
were too thin did not get nice crackles, so the result, are more about
behavior.
Now results.
I wrote all these recipes in matrix, as our software developer did not
reach to a common expansion numbers what looks high expansion in
Insight is medium in matrix. As I want to follow the results. I
do not understand too good the numbers but I can read and compare.
This one from Irene Poultton's web site:
BASE GLAZE 945deg.C. Cone 08
------------------------------------------------------------------------
----------------------------
Formula Weight% Recipe
------------------------------------------------------------------------
----------------------------
KNO 0.5552 15.51% FRIT 3110 100.0
CaO 0.4337 10.47% Calcium Carbonate (whiting) 10.00
MgO 0.0111 0.19% BALL CLAY AK 10.00
Al2O3 0.1399 6.14%
B2O3 0.0761 2.28%
SiO2 2.5257 65.33%
TiO2 0.0025 0.09%
K2O 0.0502 2.03%
Na2O 0.5051 13.48%
Al:Si 18.0538
Expan. 15.5510
ST 304.890
It did not melt with the other glazes.I could not leave it longer in
the kiln.
This one from Irene Poultton's web site too
IRENE POULTON-LARGE WHITE
CRACKL 991deg.C. Cone 06
------------------------------------------------------------------------
----------------------------
Formula Weight% Recipe
------------------------------------------------------------------------
----------------------------
KNO 0.3236 9.19% FRIT 3134 100.0
CaO 0.6739 17.05% ENGLISH KAOLIN 10.00
MgO 0.0025 0.04% SILICA 6.00
Al2O3 0.0825 3.79% Bentonite 2.00
B2O3 0.6251 19.63% Tin Oxide 10.00
SiO2 1.8548 50.28%
TiO2 0.0003 0.01%
K2O 0.0096 0.41%
Na2O 0.3141 8.78%
Al:Si 22.4814
Expan. 11.6634
ST 281.810
This is a nice, real white a good starting point!
This ash glaze
RAKU ASH (RASH) 945deg.C. Cone 08
------------------------------------------------------------------------
----------------------------
Formula Weight% Recipe
------------------------------------------------------------------------
----------------------------
KNO 0.7301 27.46% PINE ASH 20.00
CaO 0.1953 5.21% FRIT 6004 70.00
MgO 0.0747 1.43% RED CLAY (GRT) 10.00
Al2O3 0.0965 4.68%
P2O5 0.0273 1.85%
B2O3 0.5591 18.52%
SiO2 1.4234 40.73%
TiO2 0.0029 0.11%
K2O 0.3858 17.30%
Na2O 0.3442 10.16%
Al:Si 14.7473
Expan. 19.7215
ST 235.210
, I made before tested again.
Now seeing the results, it is not in the right limits,but still
interesting.
On the white tile falls off where it is thick, kind of "David Roberts"
effect, yet yellowish gold like broken glass..The same color, does not
fall off from the pink slip.I will adjust it for the next time.
About pine ash,I belive that this is the main ash I use. I think if you
want to try and make it use 30% ash,and play with the rest Remember,
Fusion frits may help you, even not, do 30 ash 70-80 frit and the rest
kaolin or other clay.
80Laguna b.
20 Nephalin
ok
More tests: I did not write correct which tile had what glaze.
So that is all.
Ababi Sharon
Kibbutz Shoval- Israel
officially Glaze addict
ababisha@shoval.ardom.co.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
http://www.israelceramics.org/
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