Lili Krakowski on tue 6 dec 05
Let me repeat, once more and again the [late] Ceil Gross's PUMPERNICKEL =
story.
In the dead of winter a serf finds the most elegant, strange and =
beautiful dog running loose in the fields. He catches the animal, brings =
it home. He and his wife have never seen anything like it, so they =
decide to take it to the Czar.=20
In the morning the man wraps the dog in the household's only blanket, =
and the wife's shawl, and puts the dog on the cart--and they drive to =
Moscow.
At the Kremlin the man explains his mission. The guards are overjoyed! =
The animal is the Czar's favorite Borzoi, and the Czar will want to =
thank the peasant in person.so he is sent to the kitchen for a meal, =
while he waits on the Czar.
The Czar indeed is overjoyed. "What can I do for you, what is your =
reward? Name it and it shall be yours" "Well" says the peasant, "the =
cook gave me the most delicious and soft and beautiful bread I ever =
tasted in my life. All I want is the recipe for that to take home to my =
wife." The Czar is incredulous, but if that is what the peasant wants.
Back home the man gives his wife the recipe. "Make this for us.It is =
absolutely delicious."
Next day the wife produces a bread. The peasant tastes it, and says: =
"This is nothing like the bread at the Kremlin. Did you follow the =
recipe?"=20
"Of course I did," the woman replies.
"Tell me just what you did, step by step."
"Fine," says the wife. "Here it says: take a pound of sweet butter.I =
should have sweet butter! I'm poor! I'm lucky to have lard--so I used =
lard. Here it says: take 4 pounds of finest white flour.We can't even =
get white flour around here, so I used the rye flour I had..."
Etc. Pumpernickel.=20
Yes, in glaze concoction one can make substitutions. But they do not all =
work alike. Or why we calculate.
When gas prices rose some 25 years ago firing temperatures dropped. And =
the general advice given was to use Neph Sy instead of feldspar to allow =
c.10 glazes to work at c.6.
Now the given melting point for soda and potash spars is around 1200 =
degrees Centigrade; and for Neph Sy 1140-1200 (this as given by Fraser) =
so it is not an overwhelming change.
The original, intended, Tony Yeh CM3/95 recipe boils down to:
Na2O 0.64, K2O 0.135
MgO 0.231, CaO 0.570, the alkalines adding to .199
Al203 is 0.212, Phosphorus is 0.82, and Silica 2.222. And Fe203 0.002
The revised, and GREEN version is:
Na20 .190, K2O .058, MgO 0.221; CaO 0.530, Alkaline total .0.248, Al203 =
0.272, SiO2 1.965, Phosphorus 0.77, and Fe2O3 0.001
This all calculated on my trusty, never rusty, Glaze Master.
As with the pumpernickel story , changes bring about changed results. =
Here the changes are
Less potash, more soda, less magnesium and calcium, so a higher amount =
of alkalines proportionately. Alumina has been raised and Silica lowered =
quite a bit.and the iron effectively halved. The phosphorus has been cut =
as well.
Essentially this is a new glaze. In this county there is a large family =
all of whom can be identified by noses that look as though they once had =
been broken. They are a handsome lot, I am not saying their noses are =
anything but nice--but also identifiable as a family trait, as is a bump =
on the nose in my Mother's family. Same here. This new glaze is a cousin =
of some sort of the Tony Yeh one.but not the same.
I played with this on my computer for hours--and the best I did so far =
was to add washed wood ash, and change to another feldspar. Thereby I =
kept the ratio of alkalines and magnesium and calcium about the same, =
but did lower the alumina level.=20
If I were testing at this point I would do--you guessed it-- straight =
line blends, first replacing Custer with a soda spar and then, if =
necessary, taking the best of any of those blends and putting Neph sy =
at the other..and blending again..
What surprises me all around is that the iron seems so low..am I doing =
something wrong here? Because that mangy little figure is all I come up =
with for a very rich brown glaze.
Lili Krakowski
Be of good courage
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