Mary/Adams on sat 17 dec 05
Back to some basics that I cannot find in books:
1. When is it OK to open the kiln? Under what temp?
2. What is a soak and why and when would I want to do that?
marianne kuiper milks on sat 17 dec 05
I'm sure you'll get better help than this, but: do you have a peep-hole? If you do, can you see the cones? (try to use goggles for high temps before you look, if poss) If you have cones, prob ^4,5,6 maybe 7 lined up, the firing can be stopped when cone 6 goes/is down, but before 7 goes down.
The temp at that point should read between 2118 and max 2269 Fahrenheit or 1159-1243 celcius, depending on your firing speed.
If that wasn't really your question: you can crack the lid open, only a bit, when you can lay your hands on the lid without burning them. There are diff opinions on that, but this one is pretty safe. The slower you open, the better the colors.
Soaking is when you keep the kiln at a certain temperature (controlling the firing) for the "soak time" suggested.
Good luck, Marianne
Mary/Adams wrote: Back to some basics that I cannot find in books:
1. When is it OK to open the kiln? Under what temp?
2. What is a soak and why and when would I want to do that?
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L. P. Skeen on sat 17 dec 05
1. When I open depends on the situation. If I"m desperate to get stuff
out, because I"m packing for a show or whatever, I'll pull the peeps at
500*F and crack the lid 30 minutes later. I generally will open the thing
up any time the temps are below whatever temp they'd get to in a household
oven.
2. Soaking is when you would hold the temperature at a certain level for a
period of time. Useful for development of crystals if you're into that.
L
----- Original Message -----
From: "Mary/Adams"
> Back to some basics that I cannot find in books:
>
> 1. When is it OK to open the kiln? Under what temp?
>
> 2. What is a soak and why and when would I want to do that?
Steve Slatin on sat 17 dec 05
Mary --
It looks like everything except part 2 of question 2 has already
been answered.
The chemical reactions that we rely on to glaze pots occur at
elevated temperatures. When we hit the right temperature, the
reactions begin. But few reactions takes place instantly.
Sometimes a reaction starts, but if you let the temperature fall,
the reaction will stop.
Some of the glaze effects many of us like most are dependent
on crystalline development. If you're in the range of chemical
effects that permits crystals to develop for just a few minutes,
you will generally get only extremely small, generally invisible
crystals. If you let them continue to grow, you can get larger
crystals, which can be seen with the naked eye. "Tea dust"
glazes and other effects suddenly become possible ...
Other glazes rely for their effects on phase separation.
(Most, if not all, 'floating' glazes are phase-separation effect
glazes, AFAIK.) Again, the longer the chemical process
continues, the more pronounced the effect.
So, do I soak every glaze? No, and maybe neither should
you. One of the changes that comes with a soak is the
development of the runny character of some glazes. Some
glazes will run right off the pot and ruin a shelf if you soak.
You've read these words too often already, I'm sure, but the
key is test, test, test. Make some glaze-catchers (AKA
'wasters' or 'diapers') and test the glazes you already like
in a soak. See what they do. The surface of your glazes
will probably have a different feel, even if there's no other
difference. (A soak smoothes out many surfaces, and may
even permit pinholes to heal.)
FWIW, you say you fire to cone 5-6. I have tested a little, and
am trying to organize my thoughts on this issue, but I'd
say that in general if analysis of your glaze shows a high
concentration of melters, and a high percentage of zinc,
boron and sodium OR some combination of these, it may
tend to run.
If your glaze has a lower concentration of melters overall,
and/or if it concentrates on other melters, like calcium,
it will probably not run. Don't take too much of a chance,
though, shelves are expensive.
A big do-as-I-say-not-as-I-do would be to note the
identity of each experiment when you glaze. If you make
tiles, you can scratch unique numbers or other identifiers
into them at the green stage; then when you glaze, write
down exactly what you're doing. This avoids the all-too-
common effect of pulling a marvelous test out of the
kiln and not knowing exactly how you did it ...
Best wishes -- Steve Slatin
Mary/Adams wrote:
Back to some basics that I cannot find in books:
1. When is it OK to open the kiln? Under what temp?
2. What is a soak and why and when would I want to do that?
Steve Slatin --
And I've seen it all, I've seen it all
Through the yellow windows of the evening train...
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