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reduction when cooling

updated mon 13 dec 99


Baery Salihberry on sun 12 dec 99

1.) Am a bit confused by the last posting from Hank in Eugene, where he
mentioned hovering in oxidation at 2100 F. with 1/3 gas pressure for 3 to 6
hours (on the way down to get a "bloody" shino..
Does this method encourage formation of cristobalite?

2.) At the other end of the cooling cycle, I've noticed a fair bit of
mention of the reduction around 1400 to 1500 F., for an hour or so, to
achieve good copper reds.
Also, I see that Nils in his first book shows reduction (on cooling) from
around 1500 to 1000 F. for good copper reds.
I had been having pretty consistent results when reducing around 1800 F.
for a half hour, but then on one particular firing I swithched to that zone
suggested in Nils' book, and ended up with muddy colors throughout.
Does anyone have any insight into this dilema? Is it possibly connected to
the type of glaze, mine being a satin matte. Perhaps the more glossy
copper reds benefit from a lower temperature post firing reduction.

I guess the ultimate rule of thumb is "do what works," but I'm really not
sure what I'm trying to achieve, since sometimes the reds are possible
without the post-firing reduction, sometimes they are enhanced, and as in
my last firing, they are diminished.

Handwork From The Heart
Baery Salihberry
3642 Glencoe Rd.
Westbank, B.C. V4T 1L8
Phone/fax: 250-768-3268