search  current discussion  categories  forms - misc 

big pots and platters

updated mon 4 dec 00


will edwards on sun 3 dec 00


We recently installed 3 new kilns to go with our older ones. New vents an=
d all
digital. So far we have had great success with large platters in comparis=
on to
our older version of kilns.
My speculation is the larger kilns with 3 inch brick have proven that slo=
cooling cycles do help.
We bisque at 04 most of the time and glost fire @^6. Bisque is a slow fir=
ramp and glost is done on medium fire ramp unless it is a dense load then=
use slow fire ramping once more.
The vents we use (I hear) should not be cut off till the kilns are under =
1000 degrees F. Maybe someone else knows more about that?
The colors are more vibrant and we see less flaws and seldom a crack at a=
I did notice we get better chrome tin colors in the older kilns than the =
with vents. Makes sense doesn't it! Also I have not seen any chrome tin p=
on any of the whites we use in the ones where the vents are running. I do=
a lot of chrome tin reds/pinks with plenty of tin in the kilns. That
observation says that LOI is certainly there and the vents pull it off as=
is expelled.
Consider the amount of chrome available. 0.35 at best 1/3rd of 1%. =

The logic is the chrome tin reds is the result of a LOI/marriage between =
available kiln atmosphere of chromium and stannic oxide. They are attract=
to each other!
This reminds me of what happens in reduction since it relies on atmospher=
e in
the kiln and developing of color through phase bonding of molecules. I wi=
sh I
knew exactly when the process occured. The exact flashpoint of chromium a=
the flashpoint of stannic oxide would tell me alot. Who knows this?
Does Hamer and Hamer contain this information. I am still waiting on my
ordering catalog so we can get those books....(Smile)
Also do any of you know if the computor calculations programs list this? =
I use
a system that I had for commercial chemistry that is not for this type of=

work. Also a hand held calculator and old fashioned testing.
And I am the fool that held off asking this question because I didn't wan=
t to
get ran through the pug-mill....(Yes I used boron in the flux column) sho=

William Edwards

Get free email and a permanent address at