Lili Krakowski on fri 14 apr 06
1.Linda writes:"Please tell how you achieve a neutral atmosphere in a
(presumed) electric kiln? Or are you using another
fuel source?"
Actually "neutral" is the more correct term for electric fire. Oxidation
fire is the fire achieved with fuel burning kilns when plenty of oxygen
(air) is introduced. Much has been written about OXIDATION fire vs
REDUCTION fire...and I certainly am not remotely expert on it. It might be
added that in kilns such as woodburners there is a constant [?] fluctuation
from oxidation to reduction and back...So NEUTRAL is the preferred term for
electric firing although I expect the same could be used for muffle kilns.
2. MAKING OR BUYING GLAZE.A friend who is a superb cook does not bake. Her
dinners end with lovely high calorie delights from a local patisserie.
Another friend adores baking, hates cooking...her evening parties feature
nibblies brought by guests and incredible deserts made by her. Another
friend is a culinary professional, cooks and bakes from scratch--or uses
mixes . Having said which: you do NOT become a better person by mixing/not
mixing your own glazes. (For directions on how to be a better person.....!)
There are some people who really truly are fascinated by glaze: how it is
achieved, what it does, how diverse firing methods affect it... Others
think of glaze as an item of clothing for the pot, nifty-poo, never mind,
put it on and go. Others, still, have different relationships with
glaze...and NO ONE is more right than others. It really depends on your
situation, your preference.
Reasons for mixing your own glaze: you are interested in glaze qua glaze.
You are interested in specific firing techniques which call for diverse
glaze fine-tuning. You make a lot of pots, use a lot of glaze, and the
economy of volume benefits you. You have a big studio, lots of space, no
problems storing raw materials, can afford to invest NOW in materials that
will last the rest of your life. You are where you are and do not plan to
move.
Reasons for buying ready mixed glazes: Your eyes glaze over (I know. You
guys expected that!) at the mention of glazes, calculation etc. The very
word "molecular" gives you heartburn. You have little studio space, have a
health consideration that makes it desirable to avoid exposure to dust as
much as possible, will most likely move in a couple of years, have no money
to tie up, produce very few pots. Last but by no means least: you are
emotionally unsuited for fine-tuning finicky work. (This is NOT a
criticism. I can spend endless time on glaze tests, not sewing. There are
different types of patience.)
I just did a quick count. I figure one needs 25 materials to start making
glazes, and this does not include tzatzkes nor colorants. Even when you
pick up the materials at the supplier, if you want a meaningful
quantity--many places give you a price break at 5 lbs--you are tying up a
goodly sum of money. And: a three pound coffee can holds about 3 lbs of
material--depending on material. A can like that takes up 6.5" of shelf
space about 9" high. Plastic gallon jugs are about 6" diam. taller than
cans. You also need sieves, scale, bowls....Yes, some supplier should offer
a starter kit...So?
Please remember and never forget: in many situations, historically, the
potters made the pots and glazing and firing was done by other
"specialists." In our time this has happened where couples worked
together...the Natzlers being a prime example.
Lili Krakowski
Be of good courage
L. P. Skeen on fri 14 apr 06
IMO, there is NOTHING that screams "amateur/weekend dabbler/newbie clay =
person/I am clueless about glazes" louder than a glaze that looks like =
paint. Those horrifying store-bought burgundy, hunter green, cobalt =
blue, etc. paint-on, solid color glazes (even if you did dip them) that =
you can see at WalMart any day of the week are just sickening, and I =
don't care HOW GOOD you are at making the work, Richard Aerni or Steven =
Hill good even, your pots will look like shit with a glaze like that, =
ESPECIALLY if it is poorly applied (and we won't even GO there now....)
WAY too many store-bought glazes look like that. The only way to make =
them interesting is to experiment with layering over/under other glazes. =
If you absolutely have to use store-bought, please do the rest of our =
eyes a favor and either go with a glaze that has some depth (Coyote and =
Opulence have a few that are interesting), or experiment with layering =
and/or altering the glaze a bit. =20
O yes, I definitely have used store-bought glazes in the past. And yes, =
I do have a handmixed glaze that looks like periwinkle paint - not =
because I WANTED that look, but because it does not move at all, and it =
has to be layered or it's boring. I have altered almost every =
store-bought glaze I've ever used by adding other colorants or =
ingredients to get what I like. :) You can do it too! Experimentation =
is the key. Down with boring glazes!!!
L
----- Original Message -----=20
From: Lili Krakowski=20
you do NOT become a better person by mixing/not
mixing your own glazes.
There are some people who really truly are fascinated by glaze: how it =
is achieved, what it does, how diverse firing methods affect it... =
Others
think of glaze as an item of clothing for the pot, nifty-poo, never =
mind,
put it on and go.
Linda Ferzoco on sat 15 apr 06
Thanks Lili. Tony Ferguson wrote me to point out
that, when one vents an electric kiln, one introduces
enough air to move the atmosphere from neutral to
oxidation.
Cheers, Linda Ferzoco
--- Lili Krakowski wrote:
> 1.Linda writes:"Please tell how you achieve a
> neutral atmosphere in a
> (presumed) electric kiln? Or are you using another
> fuel source?"
>
> Actually "neutral" is the more correct term for
> electric fire.
Ivor and Olive Lewis on sun 16 apr 06
Dear Linda,
At the elementary level Lili Krakowski is pretty well spot on with her =
analysis.=20
We can expect that the atmosphere in an electric kiln remains constant =
once organic residues that might be in a clay have burnt away. If it is =
a ventilated kiln, drawing fresh air in will bring in the usual 20% of =
oxygen. Any hot reactive free metals will be oxidised by this but since =
we are dealing with relatively unreactive oxides there seems to be no =
reason why our clay or glazes should change.
Stoking a hard fuel fired kiln will cause atmospheric cycling. Wood, =
Coal and Coke all need heat to change them into combustible gases which =
will burn and diminish the amount of free oxygen flowing through kiln =
chamber. Once you are left with hot coals you would need to close the =
damper to restrict air flow to retain an reducing atmosphere. doing this =
can result in a falling temperature. It is the task of the Kiln Captain =
to make judgements as to keeping a rising temperature and accepting the =
effects of alternating spasms of reduction and oxidation or maintaining =
a continuous reduction and oscillating temperature chart.
Firing regimens for oil and gas fired kilns can be controlled in a more =
precise manner to give either of the three alternative atmospheric =
properties.
However, though the simple answers will carry us along without bother it =
is wise to remember that the chemistries of some of our materials are =
complex. The stability of some materials is governed by their ability to =
decompose or react in other ways under the influence of reduced Oxygen =
pressure or the presence of Carbon monoxide. Those of you who wish to =
know more might well read "Introduction to Ceramics " by Kingery and =
Others and "Chemistry of the Elements" by Greenwood and Earnshaw.
I often wonder if anyone has ever deliberately fired ceramics in an =
oxygen enriched environment?
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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