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copper red advise

updated sat 7 nov 98


Susan Davy on fri 6 nov 98

Dear Donn Buchfinck,

I am a fellow clayArter and have been following the "copper red" thread
for a couple years now. And noticed your posts of late Oct. 1998.

I will give you some background first, then pose my question (s)....and
if you have time or interest or knowledge, thank you in advance for

I am a full-time potter for 24 years now....oxidation up until 1996 when
I finally bought a downdraft propane car kiln from Bailey Pottery
Equipment a 36/24...meaning that there is 24 cu ft of loading space. I
fire copper reds with an oxygen probe and get pretty good results.
Since last summer I have been experiencing a stalling effect if I try to
keep the oxy probe at the recommended .60-.62 in the 1700-1850 degree
Farenheit range. I regulate the oxy probe with the damper. Before that
time I seemed able to climb pretty well. I am wondering if it is summer
weather or what, I just do not know. So I back off the damper and fire
through that range with the oxy at .40-.55. I seem still to be getting
good results, but this stalling is very frustrating. By the time I am
at 1600 degrees F, I am at 7" H20 pressure and that seems to be high
enough. Any higher than 8" and I really stall. My blowers are on high
and the gill flap is open about 1/4 ".

I have changed the battery in the oxy several times during these firings
to make sure that is not a problem.

Again, thanks in advance.
Susan Davy
Davy Pottery