Hank Murrow on tue 14 aug 01
Mel wrote in part;
the term that i was searching for was:
>
>equilibrium, or the state at which all things in a kiln, pots, air,
>shelves, brick face and flue are at apex temperature.
>
>heat work is the name we give it..
>
>feriz said to think of the kiln loaded. it has three things
>inside....pots 30 percent, shelves and furniture 30 percent.
>air 40 percent. how that air is heated is critical. and where
>that heated air is, is critical.
>
>think about how much air is inside of every pot you make. a quarter
>inch wall, containing air. the air must be heating inside that pot the same
>as the outside. the last thing in a kiln to come to equilibrium is the air
>inside the pot. heat work will make that happen, the cone goes over
>when the air around it reaches apex. that may not be true for the
>inside of a big pot.
>
>i am sure that the work of hank murrow. in oregon has it's core in heat
>work and equilibrium. yes, crystals form, but, the long soak at
>1900 is causing the pots to reach a perfect equal heat. the glaze
>is totally done melting into the clay body. perfect maturity takes place.
>
>well, i am trying to get all of this into my mind. sharing it on
>clayart helps me get it stuck.
>
****Thanks to Mel and Feriz for this valuable post. For the record,
each firing in my Doorless Lifting Fiberkiln lasts around 24_30 hours
before I shut it down at C/10. About ten of those hours are spent above
C/5. I have gone to movies between C/.8 and C/10. The cooling soak in
Oxidation runs anywhere from 2 to 8 hours. Cost of firing (at 68 cents a
therm) is between $18 and $24. One teabowl pays for all.
Cheers, Hank
mel jacobson on tue 14 aug 01
it was my pleasure today to have a long talk with feriz.
he sends his best to his many friends that he has not spoken
to for months. he is still not able to chat...in time he will.
i also had some questions about some other writing that
i am doing and i will share them with you.
i was confused on the term `dew point`...that term is basically
used in the heat treating industry to describe the water that
forms on metal. the term that i was searching for was:
equilibrium, or the state at which all things in a kiln, pots, air,
shelves, brick face and flue are at apex temperature.
it is the goal of every potter wether in industry or working alone
to have a kiln that will reach 'perfect equilibrium'.
how to achieve this perfection has a great deal to do with how
the kiln is loaded, what kind of pots are going in, and how they
are shaped. there is not an easy answer.
so:
a kiln does not fire by itself, the same way, each time.
a great many things are happening, and how you load,
soak, how long the firing takes, how long the kiln cools,
all will have grave affects on the pots.
heat work is the name we give it..
feriz said to think of the kiln loaded. it has three things
inside....pots 30 percent, shelves and furniture 30 percent.
air 40 percent. how that air is heated is critical. and where
that heated air is, is critical.
think about how much air is inside of every pot you make. a quarter
inch wall, containing air. the air must be heating inside that pot the same
as the outside. the last thing in a kiln to come to equilibrium is the air
inside the pot. heat work will make that happen, the cone goes over
when the air around it reaches apex. that may not be true for the
inside of a big pot.
i am sure that the work of hank murrow. in oregon has it's core in heat
work and equilibrium. yes, crystals form, but, the long soak at
1900 is causing the pots to reach a perfect equal heat. the glaze
is totally done melting into the clay body. perfect maturity takes place.
well, i am trying to get all of this into my mind. sharing it on
clayart helps me get it stuck.
the word dew point came from another source...it was heat treating.
it has bothered me since that post on heat work..now it is
correct...at least in theory.
the theory of heat work is never taught. very few understand it.
potters are the last to know. we have to catch up. these ideas are
industry standards....clayart has to help spread the word...if there
is debate, wonderful...that is how it becomes fact. then understood,
then put into practice.
thank you feriz.
hard times for him, but he had time to share this information with me.
mel
From:
Minnetonka, Minnesota, U.S.A.
web site: http://www.pclink.com/melpots
Mike Gordon on tue 14 aug 01
Hi,
I was wondering if the air inside of say a large vase/bottle might be
heated by radient heat from the walls of the pot, as the outside gets
hotter and hotter.Heat transfer or something. Just a thought. By the way
Mel, your comments about your kids making 199 pots per semester is going
"On The Wall" as soon as school starts! I have to kick butt to get them
to do the one a week thing. Thrown,trimmed and glazed with 12 electric
wheels and 5 kicks. Mike Gordon, Walnut Creek, Ca.
| |
|
