WHew536674@cs.com on sun 8 aug 99
Hi all,
Let me try this question again, since it didn't get through the first time.
There is a company, International Technical Ceramics of FL, that distributes
a product called ITC100HT . It is a kiln shelf coating that is put on ONE
time only. It doesn't flake, can be put on both sides and will produce a
higher thermal rating. Has anyone out there tried it, know about it, before
I contact the company?
Joyce A
Mission, TX
105335.63@compuserve.com
Hannah Brehmer on mon 9 aug 99
Dear Joyce,
About ITC, if you check the archives, you'll find quite a few
postings about it. Here is my experience:
It definitely did not prevent glaze from sticking to the shelves. I
still had to chip it off. Someone else said they had the same
experience. I also can't see any difference in my firings, so for me at
least, it is highly over-rated and over-priced. Some people seem to swear
by it, especially Mel. (Mel, are you getting a kick- back??!!) Many
of the postings in the archives relate good results, at least in their
minds! Not in mine.
Best wishes and good firings, Hannah at
Lake Tahoe, CA
June Perry on tue 10 aug 99
Dear Hannah:
Your ITC coated shelves may be sticking because you didn't spray them. Alice
at ITC told me you needed to spray the ITC in order to avoid pots sticking.
Did you spray the ITC or paint it on?
I wish I had known about compressing the fiber before spraying. I wet mine
down very well and it did flake off some areas. I have glued some of the
fiber with sodium silicate and re-sprayed with the ITC and I'm keeping my
fingers crossed that it will hold.
The kiln I'm now using is a 22 year of Geil kiln and the fiber was starting
to shed in spots. Part of it was due to normal wear and tear and some from
rodents getting in there and deciding the fiber would make good nests! :-(
Regards,
June
Gavin Stairs on tue 10 aug 99
------------------
At 10:52 AM 8/9/99 -0400, you wrote:
=3E----------------------------Original message----------------------------
=3E Dear Joyce,
=3E About ITC, if you check the archives, you'll find quite a =
few
=3Epostings about it. Here is my experience:
=3E It definitely did not prevent glaze from sticking to the shelves. I
=3Estill had to chip it off.
2=A2:
Kiln wash is mainly a protection for the shelf. If a highly fluxed
material like glaze comes into contact with a shelf, it will eat away at
the shelf material, which weakens and eventually destroys the shelf. Kiln
wash is intended to prevent this, by interposing a barrier of highly
refractory material, usually mainly alumina. Then the glaze tries to eat
up the kiln wash, but doesn't get very far before the end of the firing, at
which point the glaze can be chipped off without damage to the shelf.
That's the basic idea. The concept is that of a sacrificial layer of
poorly cohesive material.
There is no point in washing the underside of a shelf, unless you intend to
flip it.
The flakiness of kiln wash designed for shelf protection is part of the
design: the glaze blobs will be easy to remove. If you want a coating for
the inside of a kiln, don't use kiln wash=21 It will flake, as it is
supposed to do. Use a cementous coating that makes a hard, durable
surface, and adheres to the brick, like ITC.
So, traditional kiln wash should better be named shelf wash, since that is
what it is good for.
ITC is highly refractory, but it is also a cement that adheres to the shelf
or brick, so the chipping part when used as a shelf wash may take a bit
more effort.
This is not intended to be a tutorial in refractory coatings. If you have
a specific requirement, choose a specific coating designed for the job.
Refractory manufacturers make a number of materials for coating brick,
metal, fibre, etc., as well as kiln shelves.
I know I'm up to about 25=A2 by now, but one last thing: I don't think kiln
wash should be depended on to protect expensive shelves from drippy glazes.
It should be for accidents. If you have a good idea that a pot will drip,
you should probably use a biscuit saucer underneath. Better that than ruin
a good shelf because the kiln wash was too thin, or flaked right where the
blob went. Or set the pot on a pile of dry alumina. I hate to think of
all those shelves getting beat up for lack of a little foresight.
Gavin
I'm no expert, but I know what bugs me.
Gavin Stairs on tue 10 aug 99
-------------------
...
=3E2=A2:
...
=3EThere is no point in washing the underside of a shelf, unless you intend =
to
=3Eflip it.
...
Or are using it in a salt kiln. Oh well=3B write in haste, redact at =
leisure.
Gavin
Corinne P. Null on tue 10 aug 99
I'm wondering if the variences in the results of the ITC as kiln wash has
anything to do with the type of shelf it is put on, or the firing type
(elec/gas/wood), or the composition of the glaze that still adheres to the
shelf. Perhaps if some of that information were also provided in these
posts about the shelves and ITC performance, we might find some real
information to go by.
Corinne Null
Bedford, New Hampshire
null@mediaone.net
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.UKY.EDU]On Behalf
Of Hannah Brehmer
Sent: Monday, August 09, 1999 10:52 AM
To: CLAYART@LSV.UKY.EDU
Subject: Re: Kiln Shelves and Wash
----------------------------Original message----------------------------
Dear Joyce,
About ITC, if you check the archives, you'll find quite a few
postings about it. Here is my experience:
It definitely did not prevent glaze from sticking to the shelves. I
still had to chip it off. Someone else said they had the same
experience. I also can't see any difference in my firings, so for me at
least, it is highly over-rated and over-priced. Some people seem to swear
by it, especially Mel. (Mel, are you getting a kick- back??!!) Many
of the postings in the archives relate good results, at least in their
minds! Not in mine.
Best wishes and good firings, Hannah at
Lake Tahoe, CA
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