don hunt on tue 12 nov 02
O great shino gurus on list
Is the approximate reduction schedule for red glazes about right for
shinos?
I start reduction at about 1600 f and let it climb in reduction at
around 250 per
hour with maybe a 30-45 minute oxidation soak at the end. My reds are
excellent, as I figure out the flow patterns in the kiln. Shinos in the
same load are not univerally wonderful. I realise there are maybe a
zillion variables, but if the reds are there, would you say reduction is
correct for shinos?
Thanks
Don Hunt
Dannon Rhudy on tue 12 nov 02
Don Hunt asked:
> Is the approximate reduction schedule for red glazes about right for
> shinos?..............
I start reduction for shinos a little earlier, maybe cone 012. Generally
good reds and good shinos come out of the same firings. But then,
I start reduction for reds at about cone 012, too.
I haven't noticed that it makes much difference what the climb rate
is. I keep my kiln in light reduction for the rest of the firing, once
reduction is started. You could add a few sticks of wood to the
kiln at around that time, too - sometimes gives nice carbon trap on
shino. On the other hand, it also will carbon trap with the reds,
giving grey to black on edges that would otherwise be white (on
porcelain). If shino is too thick, it will give a boring cream-to-
white surface, often - so application is a definite factor.
regards
Dannon Rhudy
June Perry on wed 13 nov 02
Many start reduction much earlier to get strong shino color -- 1250-1450 or
so fahrenheit. I think it was Ken Ferguson, who I once read, started
reduction at 1250. I'd reduce that early but I also found that at around 1450
I could still get good color.
Regards,
June
Mondloch on wed 13 nov 02
> Many start reduction much earlier to get strong shino color -- 1250-1450
or
> so fahrenheit. I think it was Ken Ferguson, who I once read, started
> reduction at 1250. I'd reduce that early but I also found that at around
1450
> I could still get good color.
Hi,
Could someone explain to me why early body reduction like this doesn't cause
black core problems since this temp range is earlier then that recommended
for complete oxidation in bisque firings.
In my Hamer book under Black Core is says "Black core occurs when the carbon
inside the body has not been successfully burnt out.... The lack of
sufficient oxygen between 750C(1382F) and 900C(1652) by an unclean
atmosphere or by too rapid a firing can lead to breakdown, bloating et at
higher temperatures...black core is often a fault arising in the bisque
firing that does not show itself until the glaze firing."
ok. So maybe there's a difference between the carbon naturally in a body
from that deposited by early reduction? But what about those of you who
single fire shino glazes if you don't get the clay's carbon all burned out
before you want to do the early redux?
confused,
Sylvia Mondloch
---
Mark & Sylvia Mondloch
Silver Creek Pottery & Forge
W6725 Hwy 144
Random Lake ,Wi 53075
HotArt@silvercreekpottery.com
http://www.silvercreekpottery.com
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