search  current discussion  categories  kilns & firing - coatings 

salt and itc - mel, please read

updated fri 4 jun 99

 

Bruce Girrell on wed 2 jun 99


> One of Feriz most emphatic requests was based on the theory that
> a kiln must
> breathe air on all sides, in other words, "do not build it on a
> solid concrete or block base".


Mel,

I do not understand the idea behind this. Why did Feriz consider this to be
so important? Whose theory says that a kiln must breathe on all sides? What
effects would he expect to see if the kiln had had a solid base?

When I asked about this after the CM article appeared, you said something to
the effect of "it was old potter's knowledge" and I just accepted that it
was one of the many, many things that I have yet to learn about this craft.
Yet you go on to say "This became a challenge to us..." which indicates that
it is something uncommon enough that you had never done it before.

One other question before I let you go. You said "I was advised by Feriz to
give extra heavy coatings to the modules" and "I then sprayed the kiln
inside with a second coat of ITC100 H.T. with heavy applications to the
lamination and modules. I used at least 5 coats on the fiber surfaces."

The instructions that came with my bucket of ITC simply said "spray a thin
coat." Were the extra coats warranted because of the intended use as a salt
kiln, because you were applying over fiber rather than brick, because you
should always apply the product heavily, or what?

Thanks,

Bruce Girrell

Dave Finkelnburg on thu 3 jun 99

Bruce,
When Mel described this to me last month at a very wonderful workshop at
De Anza College near San Francisco, I got the impression that the issue of
"breathe air on all sides" really had to do with creating thermal isolation
of the kiln from the ground/foundation. That foundation can be an effective
heat sink or insulator, depending on how the kiln is built, creating a
different rate of thermal expansion/contraction for the kiln bottom than for
the rest of the kiln. This naturally could set up some stresses the kiln
could do better without. I personally suspect that putting a kiln on legs
as Fredrick Olsen's kits and many others do, would accomplish much the same
thing, just with some added complication of a welded steel frame.
Dave Finkelnburg in Idaho

-----Original Message-----
From: Bruce Girrell
To: CLAYART@LSV.UKY.EDU
Date: Wednesday, June 02, 1999 5:09 PM
Subject: Re: salt and itc - Mel, please read


>----------------------------Original message----------------------------
>
>> One of Feriz most emphatic requests was based on the theory that
>> a kiln must
>> breathe air on all sides, in other words, "do not build it on a
>> solid concrete or block base".
>
>
>Mel,
>
>I do not understand the idea behind this. Why did Feriz consider this to be
>so important? Whose theory says that a kiln must breathe on all sides? What
>effects would he expect to see if the kiln had had a solid base?
>
>When I asked about this after the CM article appeared, you said something
to
>the effect of "it was old potter's knowledge" and I just accepted that it
>was one of the many, many things that I have yet to learn about this craft.
>Yet you go on to say "This became a challenge to us..." which indicates
that
>it is something uncommon enough that you had never done it before.
>
>One other question before I let you go. You said "I was advised by Feriz to
>give extra heavy coatings to the modules" and "I then sprayed the kiln
>inside with a second coat of ITC100 H.T. with heavy applications to the
>lamination and modules. I used at least 5 coats on the fiber surfaces."
>
>The instructions that came with my bucket of ITC simply said "spray a thin
>coat." Were the extra coats warranted because of the intended use as a salt
>kiln, because you were applying over fiber rather than brick, because you
>should always apply the product heavily, or what?
>
>Thanks,
>
>Bruce Girrell
>