liz gowen on thu 12 nov 09
Mel,I will try the cool then relight and take it back up. That I think =3D
would
allow the reduction for the gas pressure damper, in ratios that seemed =3D
to
work. I am new to gas firing so am not only learning the reds but how to
fire a reduction kiln and appreciate all feedback.... I did try putting =3D
a
pot with a pink blush on the rim in an electric ^6 firing but it came =3D
out
unchanged. This was not a slow cool so may try on my next electric slow
cool...Liz
good reduction is needed, but cooling is the key.
slow cool, and re/light the kiln at about 1700, take it back
to 1900F and let it cool again.
nils has written about this often, pete pinnell has done many tests on =3D
the
cooling of both copper and iron red.
dannon has done a lot of research in the cooling cycle of red.
it is easy to get that coleman all red fired kiln.
all the same.
slow cool, re/lite/ cool again.
pete has used a bright light and watches the color change from =3D
white/green
to sploches of red at about 1750F. he has also taken pots that did not =3D
turn
red, electric fired them and slow cool again..bright red. so. go figure. =
=3D
mel
many famous copper reds in asia are a mixed
bag...red/white and green. all on one pot.
from: minnetonka, mn
website: http://www.visi.com/~melpots/
clayart link: http://www.visi.com/~melpots/clayart.html
new book: http://www.21stcenturykilns.com
liz gowen on thu 12 nov 09
Dannon, I used three copper red glazes in the first firing and got =3D
different
red from each I chose until I get the firing down to use the =3D
commercially
made Tom Coleman since it gave the best red and would be one less =3D
variable.
Found a good medium coat also came out best. Since I have such an uneven
kiln right now about 300 F different top to bottom I start reducing at =3D
1650
on the bottom use an oxyprobe, and 2 temp probes as well as cones. As =3D
per
other emails I will be adjusting the stacking and side space to try to =3D
help
even the firing out. I guess I can't quite get my mind around why the =3D
copper
wouldn't reoxidize if slow cooled through the original temp it got its
reduction in if I slow cool in oxidation. My only good reds so far came =3D
from
a crash cool. I would just like to pevent breaking some of the larger =3D
bowls
letting the fiber kiln cool naturally. I did get some blushing on the =3D
cooler
shelf and some pink rims so think may need to reduce a bit eralier than
1650? ..Liz
I have generally good success with copper reds, and
it does seem to me that it is about the firing cycle. There are a =3D
number of
good copper red recipes available. I like Pete Pinnell's copper red's =3D
best.
The glazes do not run on my clay at cone 10; many copper reds DO run, a
serious annoyance.
Getting reds to turn red doesn't take a genious - it just
takes some patience and attention to detail. Use a good
glaze, apply a good medium coat, start reduction early
(012, for me), keep in mild
reduction on the way up. On the way down, don't
worry re: reduction. If the coppers were made, they
were made on the way UP. They need a very slow
cool to show up reliably. So take some time between
about 1900 F and 1500F. Unless your kiln cools very
slowly naturally, re-light it and leave it on low or whatever will hold =3D
it
to a slow cool; turn it off when you've gotten
below 1600F (or so). I try to take between 2 and 3 hours
to get down to 1600. Seems to be enough. The kiln does
not matter as much as one might think. I've gotten consistent copper =3D
reds
at cone 010 (raku temp); cone 7, cone 9-10, in everything from a top-hat
raku kiln to a commercial raku kiln fired to cones 7 & 10, to flat tops =3D
at
cone 9-10.
Since I've varied everything else pretty widely, it does
seem to me that a stable glaze and a slow cool affect
copper reds most.
regards
Dannon Rhudy
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