Ababi on sat 16 mar 02
It might look to you like a big headline, but I will try to explain
myself.
The idea came from an article in the PMI Fall 1998. The potter Martha
Puckett Explained how to make sawdust kiln and how to use it.
I did not succeed but one thing,about glazing in oxidation first than
making the sawdust firing from that article returned to my mind
lately.
When for a while, I did not use my raku kiln, I used it as a table for
plaster basins for drying porcelain's slurry.
I wrote on a paper tag the kind of claybody I had there.
What a surprise!
This tag survived 2 raku firing. On one hand a great surprise. My kiln
is well isolated. On the other hand, my kiln cannot raise above ^08 or
might not even reach there.
I work alone, no helper. I must be carful also a very small yard.
Safety is first. So I am not using sophisticated torches to increase
the firing speed.
I wanted to use ^06 raku glazes and always failed. I mean glazes with
more than 0.15 mol Alumina. It can allow me to use more kaolin for
suspension and more freedom in the recipe.
I had two recipes that I did not like so I tried over a year to develop
other glazes.
Being lazy on one hand b( I got four hands) hate burnishing and
being a curious person on the other hand brought me to try some
porcelaneous charactered claybodys.
The main two were
Based on Val Cushing, but simplified according to what I have:
40 plastic kaolin Either EPK or Kaolin D'arvor
20 Ball clay AK from the UK.
18 talc
12 alumina
10 molochite.
It gave me fine white, pleasant to use claybody. Good for hand building
and for the extruder.( I cannot use wheels)
As paper clay must be thick, too delicate and fragile as thin.
I tried this claybody offered by John Britt.His words:
>I have got a great Porcelain Raku Body.
>I think it is from Nicholas Bernard. It was in an old CM, but I
forgot
>the
>date.
>The parts recipe is:
>EPK -150
>OM-4 -60 I used AK
>Wollastonite - 25
>Talc - 5
>Macaloid -1 I used bentonite
>Grog 50
>Mix with 1 gallon of cider vinegar and age.
This is a very white claybody sometimes, cracks in the bisque however
even so , survives in the next, raku firing.
I cannot tell, could be because I used one size grog as he had wrote to
use fine and medium.
I tried other claybodies too. I had a strong reason. My supplier for
years convinced me that his K-129 of Vingerling was the best and not
every claybody could survive in raku.
I give you some bodies I tested:
Loess Raku
==========
BALL CLAY (AK)...... 30.00 29.41%
TALC................ 30.00 29.41%
EARTH............... 20.00 19.61%
SILICA SAND......... 20.00 19.61% Simple from the sea shore
BENTONITE........... 2.00 1.96%
It survived the raku misery but was not so special, could be for copper
glazes as it was an iron bearing material ( the soil)
The next firing, I think I used instead of sand, crushed send stones,
Survived too.
I moved lately to Paper clay, I made this claybody that I was almost
sure, would pop like pop corn in the kiln. It passed the misery in one
piece.
I want to say, that for wares with a round foot I make small hole in
the top, to avoid the pop corn syndrome.
5.5 Paperclay raku body (Expansion:5.5)
D`ARVOR KAOLIN 1050
BALL CLAY (AK) 600
TALC 450
BENTONITE 150
Feldspar Soda F7/SE 750 This is Italian feldspar a lot of Silica
+ paper pulp
It gave nice color to my variation to the lustrous blue, I lost it but
I will recover. Perhaps I will find it in the clayart archives. I made
it with Magnesia to arrive some how to violet
So the laziness of burnishing gave led me to bigger knowledge!
OK
So what do we have in this point.
A) You can use more than what your supplier offers you.
B) Do not dump the eggs cartons.
OK/2
The new raku
============
I fire my works to 1000C once to 1060.
I glaze them and fire in my electric kiln to 1000C
The results are ugly pots
I fire now to red light in my raku kiln, just below the bubbling and
put into the reduction pails.
This way i can use an oxidation glaze, I can overcome the absence of
the Gerstley borate and still have raku ware.
It costs more?
Can be, but it works!
Here is the recipe I found, I think in the ceramic web. It might look
to you familiar! It gave the best white crackles over the Nicholas
Bernard's Claybody.
The original name was white from 08 to 04
WHITE 1000C
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 06 991 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
FRIT 3124 10.00
GB Average 60.00
Nepheline Syenite 20.00
ULTROX 10.00
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.235 8.27%
CaO 0.637 19.04%
MgO 0.128 2.74%
Al2O3 0.148 8.02%
B2O3 0.654 24.24%
SiO2 0.908 29.07%
ZrO2 0.131 8.62%
K2O 0.029 1.46%
Na2O 0.206 6.81%
Al:Si 6.15
Expan. 8.72
ST 310.88
you can use any oxidation glaze for ^06 or up to 04 for this work. Tom
buck explained me that for good lustrous glaze you should have a glaze
like the next one. This is an Italian frit. Bath potters supply has a
similar
frit(soft borax frit) just remember as it has more than 30% B2O3 it is
good only for a
few days.
BRIGHT RAKU COLOR
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Cone 06 991 deg.C. -
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
FRIT F-5 85.00
ENGLISH KAOLIN CC31 15.00
ULTROX 10.00
Copper Carbonate 8.00
It can be of course other variations of oxide. in any case I use 1
copper oxide for light reduction flashes.
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
Seger Weight%
KNO 0.607 17.69%
CaO 0.391 8.66%
MgO 0.002 0.03%
Al2O3 0.164 6.59%
B2O3 1.087 29.88%
SiO2 1.303 30.92%
ZrO2 0.128 6.22%
TiO2 0.000 0.01%
K2O 0.222 8.25%
Na2O 0.385 9.43%
Al:Si 7.96
Expan. 10.45
ST 243.79
This recipe is a base for colors with the hope to see them later too,
the way Tom Buck explains in his article that you can see in
http://digitalfire.com/education/glaze/buckraku.htm
What else:
Did you think of adding your copper glaze to the wax resist?
Thought about it today!
Another thing: I reduct with newpaper s and hay. I have a big fan that
takes the smoke away from me.
This is all.
over a year I only tested and retested now I can raku.
Ababi Sharon
Kibbutz Shoval- Israel
goes deeply in glazing
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
http://www.israelceramics.org/
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