David Hendley on thu 30 aug 07
Mel, I hate to sound so argumentative and critical, but here
is my take on your copper red pronouncements:
I think the Geil/Coleman copper red ad is a fake. There
is not enough space above the pots, under the next higher kiln
shelves, to account for loading the kiln and then having the
pots shrink in the firing. The pots may have been fired in that
kiln, but already-fired pots were loaded into the kiln for the
photo-op.
The exact temperature that will produce the best copper
red is not absolute - cone 9 does not necessarily mean light
red. Excess silica makes for the light red-to-pink color.
If the glaze is formulated to fire at cone 9, it can produce
bright red at cone 9. I bet Diana P. has a cone 6 bright copper
red. Likewise a copper red glaze can be formulated to
give a bright red at cone 10+.
I have tried refiring failed copper reds in my slow-heating and
slow-cooling (fired down) bisque firing. All I ended up with
was pots the exact same color they were when they were
loaded, only now they had lovely sharp pin-hole craters in
the glaze.
I don't think anyone fully understands everything involved
in producing beautiful reliable copper red glazes. It is complex
and never easy.
David Hendley
Maydelle, Texas
david(at)farmpots(dot)com
http://www.farmpots.com
----- Original Message -----
> making a kiln full of red like the geil ad, and tom coleman
> is almost easy. that is not a faked ad. the entire kiln was fired
> to get pure red. that is the smart way to fire....all of one glaze.
> then you control the conditions. 12 glazes..temmoku, red, shino,
> white....often
> do not mix well.
> a few ideas.
>
> the actual heat/cone that you use is very
> important.
> light red at 9, bright red and 10, purples at 10+.
>
> the kiln must reduce all the way through the firing.
> it does not have to be heavy...just complete.
>
> red turns red on the way down...the cooling phase.
> so.
> slow the cooling. in fact...the down/fire method is just
> a way to insure the pots/glaze goes through the
> cooling phase slowly. if you bring the kiln back to 1900 and
> then cool, the pots go through that phase twice.
>
> (pete pinnell has re/fired green pots to bisque temp..a slow
> cool and they turn red.) that test in itself should give you
> a great deal of information.
>
mel jacobson on thu 30 aug 07
making a kiln full of red like the geil ad, and tom coleman
is almost easy. that is not a faked ad. the entire kiln was fired
to get pure red. that is the smart way to fire....all of one glaze.
then you control the conditions. 12 glazes..temmoku, red, shino,
white....often
do not mix well.
a few ideas.
the actual heat/cone that you use is very
important.
light red at 9, bright red and 10, purples at 10+.
the kiln must reduce all the way through the firing.
it does not have to be heavy...just complete.
red turns red on the way down...the cooling phase.
so.
slow the cooling. in fact...the down/fire method is just
a way to insure the pots/glaze goes through the
cooling phase slowly. if you bring the kiln back to 1900 and
then cool, the pots go through that phase twice.
(pete pinnell has re/fired green pots to bisque temp..a slow
cool and they turn red.) that test in itself should give you
a great deal of information.
if your kiln does not fire uniformly, the reds will not be uniform.
i love to fire re/fire reds at the bottom hot spot of my kiln.
strange things happen, like bright blue. or, half blue/half red.
it is the liver color that drives most potters nuts.
that meat/liver puke color. bright reds come with heat, reduction
and slow cooling. if you fire to a safe 9....liver.
you will learn how to control the thickness of the glaze. thin glazes
to not react well to red. thick...a little sag..bright purple to red.
that is really nice.
we used to call kurt's red...`dependable red`/it was often a bright green.
the glaze was fine...the firing stupid. we learned how to make red
and get it all the time.
it is almost dependable.
mel
from: mel/minnetonka.mn.usa
website: http://www.visi.com/~melpots/
Clayart page link: http://www.visi.com/~melpots/clayart.html
Dannon Rhudy on thu 30 aug 07
Mel said:
> it is the liver color that drives most potters nuts.
> that meat/liver puke color. bright reds come with heat, reduction
> and slow cooling. if you fire to a safe 9....liver.
Mel, in my copper red work, I've noted that two things seem
to affect that liverish color: brown clay(s) when the glaze is
too thin - the clay shows through the thin red glaze - not
pretty. And, sometimes, a smoky kiln will muddy red glazes
in a visually unpleasant way.
I have fired certain red glazes to cone 9 with clear red
results, but - depends on the glaze. I've gotten copper
reds at cone 6 and cone 7 repeatedly - so temp is not
necessarily the key. Pete's Orange red fired to cone
9, all else being equal, is a red glaze. But, at cone 9 it
is matt (in my experience), slightly rough to the touch.
It's meant for cone 10.
regards
Dannon Rhudy
Mark Issenberg on fri 31 aug 07
I went to NCECA a week early to take the Coleman workshop in LOSTWAGES also
known as Las Vegas.. He did a firing of his Geil.. The wind was going pretty
good. At the end of his workshop he opened the kiln that had been firing and
he had a full red load. I also had some amazing black clay shino pots that
were in strange areas of the kiln ,like under the lower kiln shelve ..
I saw Tom Coleman fire and unload a red load of pots from a Geil kiln
Mark
see you all at Perspectives to nite
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Earl Brunner on fri 31 aug 07
Whether or not the picture of Coleman's Geil firing is posed or not, and ho=
nestly, how many ad shorts aren't? I will say this. At the Las Vegas NCECA=
Coleman help a pre-NCECA workshop and people brought pots, and I believe r=
eds from all over the country, different clays, and galzes, and fired them=
in a full load of red in his kiln. The firing came out essentially the s=
ame, with all of the different variables of glaze application etc, that is =
pretty amazing. I have worked in his studio (the one of that period) and se=
en the kiln fired numerous times, the results are consistent.=0A=0A=0A-----=
Original Message ----=0AFrom: David Hendley =0ATo: CLA=
YART@LSV.CERAMICS.ORG=0ASent: Thursday, August 30, 2007 8:52:55 PM=0ASubjec=
t: Re: some red theory=0A=0A=0AMel, I hate to sound so argumentative and cr=
itical, but here=0Ais my take on your copper red pronouncements:=0A=0AI thi=
nk the Geil/Coleman copper red ad is a fake. There=0Ais not enough space ab=
ove the pots, under the next higher kiln=0Ashelves, to account for loading =
the kiln and then having the=0Apots shrink in the firing. The pots may have=
been fired in that=0Akiln, but already-fired pots were loaded into the kil=
n for the=0Aphoto-op.=0A=0AThe exact temperature that will produce the best=
copper=0Ared is not absolute - cone 9 does not necessarily mean light=0Are=
d. Excess silica makes for the light red-to-pink color.=0AIf the glaze is f=
ormulated to fire at cone 9, it can produce=0Abright red at cone 9. I bet D=
iana P. has a cone 6 bright copper=0Ared. Likewise a copper red glaze can b=
e formulated to=0Agive a bright red at cone 10+.=0A=0AI have tried refiring=
failed copper reds in my slow-heating and=0Aslow-cooling (fired down) bisq=
ue firing. All I ended up with=0Awas pots the exact same color they were wh=
en they were=0Aloaded, only now they had lovely sharp pin-hole craters in=
=0Athe glaze.=0A=0AI don't think anyone fully understands everything involv=
ed=0Ain producing beautiful reliable copper red glazes. It is complex=0Aand=
never easy.=0A=0ADavid Hendley=0AMaydelle, Texas=0Adavid(at)farmpots(dot)c=
om=0Ahttp://www.farmpots.com=0A=0A=0A=0A=0A=0A=0A=0A----- Original Message =
-----=0A> making a kiln full of red like the geil ad, and tom coleman=0A> i=
s almost easy. that is not a faked ad. the entire kiln was fired=0A> to g=
et pure red. that is the smart way to fire....all of one glaze.=0A> then y=
ou control the conditions. 12 glazes..temmoku, red, shino,=0A> white....of=
ten=0A> do not mix well.=0A> a few ideas.=0A>=0A> the actual heat/cone that=
you use is very=0A> important.=0A> light red at 9, bright red and 10, purp=
les at 10+.=0A>=0A> the kiln must reduce all the way through the firing.=0A=
> it does not have to be heavy...just complete.=0A>=0A> red turns red on th=
e way down...the cooling phase.=0A> so.=0A> slow the cooling. in fact...th=
e down/fire method is just=0A> a way to insure the pots/glaze goes through =
the=0A> cooling phase slowly. if you bring the kiln back to 1900 and=0A> =
then cool, the pots go through that phase twice.=0A>=0A> (pete pinnell has =
re/fired green pots to bisque temp..a slow=0A> cool and they turn red.) th=
at test in itself should give you=0A> a great deal of information.=0A>=0A=
=0A________________________________________________________________________=
______=0ASend postings to clayart@lsv.ceramics.org=0A=0AYou may look at the=
archives for the list or change your subscription=0Asettings from http://w=
ww.ceramics.org/clayart/=0A=0AModerator of the list is Mel Jacobson who may=
be reached at melpots2@visi.com
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