W J Seidl on mon 18 sep 06
I have to chime in here.
Absolutely, Elizabeth! Brava!
One of my favorite glazes is June Perry's Yellow, which is a (gas) =
reduction
glaze for cone 10 (it's in the archives, you can find it there)
However, when this glaze is fired on porcelain, in an electric =
(oxidation)
to cone 10, it is the most glorious "oatmeal with specks". Killer over =
and
under "my" Tenmoku...(another borrowed glaze from the archives).
Another favorite of mine is a Green Oribe (also in the archives). =
Because I
didn't have the recipe specific feldspar, I substituted another. I =
fired it
in oxidation, not reduction (cone 10) on porcelain. One layer comes out
almost white. Two layers comes out the most brilliant aqua I have ever =
seen.
I'm a fool for aqua like some folks are for MIL Blue (no offense Mel).
Three layers comes out forest green dark. I call these glazes my own =
now,
but with credit for the original, such as "SO-and-so's =
whatever...modified
by..."
Grab a glaze from the archives for whichever cone you fire. Play with =
it.
Oxidation, reduction, some of each! Keep copious notes so you can =
duplicate
the differing effects you are sure to get. Try them on each of your clay
bodies. Make sure they're safe, and within limits.
Try it over your other glazes, under them. One or two dips, or three, =
go
wild.
Keep copious notes so you can duplicate the effects. Firing times,
temperature and heat work ramps, atmospheric conditions, or just what =
button
you pushed. You decide what information is important, but "I dunno" =
isn't
going to fly with other potters. Reread that last sentence. Commit it =
to
memory.
Did I mention keeping copious notes so you can duplicate the effects?
WOO HOO! The world of glazes is an oyster, and someone taught me how to
shuck.
Best,
Wayne Seidl
Key West FL
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Elizabeth
Priddy
Sent: Monday, September 18, 2006 1:26 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: ash questions/discussion
An additional thought to what mel said about this:
SNIP
And on to another point. You do not have to
reformulate cone 6 glazes to go from gas to electric.
Just use existing cone 6 or whatever glazes and the
difference in atmosphere will change the nature of the
electric fired glaze substantially.
So you don't have to change all your cone 10 glazes
with a formula conversion, just use cone 6 glazes.
Reduction and all that will be the other differing
factors.
It is a place to start.
SNIP
mel jacobson on mon 18 sep 06
there are some very critical thoughts and ideas that
need to be re/affirmed when talking about ash glaze/temp.
of course this is not limited to ash glazes.
flux:
any material that lowers the base melting point of other materials.
(loose translation)
when a flux is added, the melting point changes.
so, for example, if you add lead to ash...it really lowers the melting point.
i have used volcanic ash for years. i, when available, used
gertsley borate as the flux. i could slide the amount of gertsley
to achieve from raku glaze to cone 11 stoneware using the
same materials...volcanic ash and gertsley borate. i used a
mix of 60/40 for a nice cone 4 school base glaze. made it in 50
gallon batches. i reversed it for raku/ 70 gert, 30 ash.
same for cone 11 90 ash, 10 gertsley.
i added a bit of zircopax when i needed opacity.
when potters do a bit of reading and understand what flux does....
it changes your entire approach to making your own glaze.
this is not complex...ph.d. chemistry. it is just common and
standard knowledge of how glaze works.
there are others on this list that go into this in greater/more
chemistry related terms. but, even a basic knowledge of what
flux is, does, and what they are....make your life as an experimenter
really interesting. once you know about flux, you do not have to
ask base questions like: can i use wood ash at cone 6 electric?
the answer is...of course.. YES, YES YES...FLUX IT.
how much/what best flux? you will determine that with experimentation.
all glaze materials are used in many combinations, for many
surfaces and temperatures. it is up to the potter to pick a
kiln that you like, a temperature that the kiln will fire to, in comfort.
and, boy...do i stress comfort. if your gas kiln will not reach cone
11 with ease...and it stresses you...change your cone/glaze
mix. i would fire cone 6 reduction...and make the firing easy.
there are thousands of cone 6 glazes out there...why fight
cone 11? buy a kiln, pick a cone, make the clay and glaze
work for you.
my god son, lives in denver....we built him a nice small stoneware
kiln. house gas pressure. home made burners.
he had a wonderful pallet of cone 6 glazes he was using already.
so.
he just has fired his gas kiln with those glazes...great stuff.
and, denver is a mile high. gas pressure is low from the house.
so, why fight it? make a system that is comfortable, and not
fight the kiln for twenty hours to cone 11.
often potters see another potter that is using ash glaze, or salt, or
some other system of firing and glaze...right away they think:
`oh man, i have to do that too.` fight that thought.
work with what you do...make it you, make the pots with your kiln,
your glazes better. the grass is brown on the other street.
just fertilize your own. make it greener.
mel
as i have said a hundred times on clayart
`if the cover of cm is your next series, and then the next
month it changes again..you are deep do do.`
from: mel/minnetonka.mn.usa
website: http://www.visi.com/~melpots/
Clayart page link: http://www.visi.com/~melpots/clayart.html
Elizabeth Priddy on mon 18 sep 06
An additional thought to what mel said about this:
The amount of play you have inyour formulations and
glaze mixing method is all up to you.
It is not true that your recipe should come out
exactly like the person who gave you the recipe.
The fact that they get compulsive with a gram scale
will make their glaze have certain characteristics
that your scoop and eyeball method will generate
effortlessly, just allow yourself the permission in
your mind and your spirit to do it your way.
The variation that makes yours special may just be a
matter of how much astigmatism you have when
eyeballing a cup of powder.
This is a ridiculous example. But it is making a
point.
For instance, if I and Ron Roy were mixing a glaze,
the same glaze with the same materials and the same
tools...we could come up with something slightly
different in firing just because we are two different
people measuring and weighing.
Or it could come out exactly the same because minor
variations do not make a difference with that glaze.
And on to another point. You do not have to
reformulate cone 6 glazes to go from gas to electric.
Just use existing cone 6 or whatever glazes and the
difference in atmosphere will change the nature of the
electric fired glaze substantially.
So you don't have to change all your cone 10 glazes
with a formula conversion, just use cone 6 glazes.
Reduction and all that will be the other differing
factors.
It is a place to start.
And like I described to a friend who said not to serve
her butter substitutes because she hated them. I told
her to get her mind right. That a yogurt spred is a
yogurt spread, not a butter substitute. It tastes
like a pretty good creamy spread for toast, not
butter.
She gave it a try, and I think she actually likes it.
Now she has a choice of which way to smear her bagel.
Try to look at it like that with regard to glazes.
E
And I know that you think you can't get shino effects
with cone 6 glaze formulas. You are wrong about that.
Ask Diana Pancioli.
Elizabeth Priddy
Beaufort, NC - USA
http://www.elizabethpriddy.com
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Lee Love on mon 18 sep 06
On 9/18/06, Elizabeth Priddy wrote:
>
>
>
> And I know that you think you can't get shino effects
> with cone 6 glaze formulas. You are wrong about that.
> Ask Diana Pancioli.
>
I have a cone 6 recipe we used in the cool spots of Craig Edwards old
woodkiln. We blended it with cone 10 shino for the middle temps.
The original shinos weren't fired much hotter than 2000*F, only for
over a week.
--
Lee in Mashiko, Japan
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
Ivor and Olive Lewis on tue 19 sep 06
Dear mel jacobson=20
<any material that lowers the base melting point of other materials.
(loose translation)
when a flux is added, the melting point changes.>>
Sorry Mel but you are way of course with this one.
Point 1. Changing the composition of a glaze affects it Maturing =
Temperature. It has no effect on the melting point of any of the =
ingredients.
Point 2. Adding compounds called fluxes that are carbonates of Group 2 =
Alkali Earth Metals will increase the maturing point of a glaze. They =
will have no effect on the point at which that ingredient with the =
lowest melting point will change state from solid to liquid.
It would be better to preach that some materials with low melting points =
have an ability to dissolve higher melting point ingredients. Lead oxide =
and Boron compounds have that property. Increasing the proportion of =
such materials will reduce the maturity temperature. The very first =
glaze I ever made (Circa 1957) was a mixture of Red Lead and Clay. =
Matured at about 900 deg C.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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