I.Lewis on wed 22 dec 99
------------------
To Tony and others who have responded with their observations,
Thank you for confirming that silicon cabide shelves do foam in a salt glaze=
firing.
Those Drips? In the pipe making trade they were known as =22snotters=22. I =
prefer Tony's linguistic invention.
I still have my shelves but they have reached the stage where I would not =
trust them with a heavy load even though the effect was mostly along the
edges. They were protected with Alumina hydrate-Kaolin wash but there is no =
guarentee that the salt vapour did not penetrate this and cause interstitial
damage
Now the question remains, what=92s going on between the Salt and the Silicon=
carbide? Is the Sodium chloride reacting with the Carbon or with the =
Silicon,
or both? Is it possible that Silicon tetrachloride or Carbon tetrachloride =
are bubbling through Sodium silicate which might be the medium forming the
rigid foam. But that seems to be a bit far fetched. Anyone else know of a =
solution to this one?
All the best for the festive season.
Ivor Lewis.
Louis H.. Katz on fri 24 dec 99
------------------
I always assummed that it was a reaction with the binder and silica and the
Soda,bubbling away just like any other glaze loaded full of Silicon carbide.
By the way I have started gathering the crudy glass from behind my bagwall =
on a
steel rod like a glass blower does in an attempt to keep it from eroding
the wall heavily. It seems to work.
Louis
=22I.Lewis=22 wrote:
=3E ----------------------------Original message----------------------------
=3E ------------------
=3E To Tony and others who have responded with their observations,
=3E
=3E Thank you for confirming that silicon cabide shelves do foam in a salt =
glaze
firing.
=3E
=3E Those Drips? In the pipe making trade they were known as =22snotters=22.=
I prefer
Tony's linguistic invention.
=3E
=3E I still have my shelves but they have reached the stage where I would =
not
trust them with a heavy load even though the effect was mostly along the
=3E edges. They were protected with Alumina hydrate-Kaolin wash but there is=
no
guarentee that the salt vapour did not penetrate this and cause interstitial
=3E damage
=3E
=3E Now the question remains, what=92s going on between the Salt and the =
Silicon
carbide? Is the Sodium chloride reacting with the Carbon or with the =
Silicon,
=3E or both? Is it possible that Silicon tetrachloride or Carbon =
tetrachloride are
bubbling through Sodium silicate which might be the medium forming the
=3E rigid foam. But that seems to be a bit far fetched. Anyone else know of =
a
solution to this one?
=3E
=3E All the best for the festive season.
=3E
=3E Ivor Lewis.
David Hendley on sat 25 dec 99
Hello Ivor,
I say that salt has nothing to do with the foam that forms
on silicon carbide shelves.
I get the same effect in my wood fired kiln. The tops of the
shelves are coated with kaolin/aluminum hydrate, and show
the effects of ash melting on them. The uncoated sides &
bottoms are covered with foam. In spots that get a lot of
fire, the foam starts to form drips.
It's a simple matter to clean the foam off - just a quick rub
down and it's off.
In my kiln the tops of the fireboxes & bottom of the kiln is
silicon carbide shelves. On the bottoms of these shelves,
which are never cleaned, big drips form, and eventually drop
into the fireboxes.
I "trust" these shelves completely. I think the foam is simply
on the surface, and has in no way affected the interior mass
of the shelves.
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: I.Lewis
To:
Sent: Wednesday, December 22, 1999 8:03 AM
Subject: Silicon Carbide Shelves and Salt Glaze
----------------------------Original message----------------------------
------------------
To Tony and others who have responded with their observations,
Thank you for confirming that silicon cabide shelves do foam in a salt glaze
firing.
Those Drips? In the pipe making trade they were known as "snotters". I
prefer Tony's linguistic invention.
I still have my shelves but they have reached the stage where I would not
trust them with a heavy load even though the effect was mostly along the
edges. They were protected with Alumina hydrate-Kaolin wash but there is no
guarentee that the salt vapour did not penetrate this and cause interstitial
damage
Now the question remains, what's going on between the Salt and the Silicon
carbide? Is the Sodium chloride reacting with the Carbon or with the
Silicon,
or both? Is it possible that Silicon tetrachloride or Carbon tetrachloride
are bubbling through Sodium silicate which might be the medium forming the
rigid foam. But that seems to be a bit far fetched. Anyone else know of a
solution to this one?
All the best for the festive season.
Ivor Lewis.
Nikom Chimnok on mon 27 dec 99
Hello ITC proponents,
I need some ammo (no, not for shooting capitalists!)
The outfit I work for has just decided to purchase a 5.5 cubic meter
(roughly 200 cubic feet in Amerikansky) modular ceramic fiber double car
kiln which will be fired often to cone 6-7. They intend to use it as bare
fiber, without even a rigidizer. They also want to do some firings with
terra-cotta sprayed with soda ash, which I suspect would eat the fiber
really fast.
The contractor has heard of ITC, and doesn't like it. Says it leads
to cracks between the modules. I suspect this might result from
misapplication. Anybody have anything to say about this? From my experience,
I'd give this kiln about a 2 year life expectancy if the fiber is left
untreated--a terrible waste in a kiln that's going to cost around $25,000.
If anyone, especially an industrial user, could present me with a
convincing testimonial, I would be most appreciative. I have about six weeks
left to do battle--wish Alice and crew had E-mail, as I can't start making
lengthy phone calls to Florida. As you can see, what's been said on Clayart
over the past couple of years has left me convinced. But I guess I'd also be
interested to hear from anyone who is not convinced. Life would certainly be
a lot easier if I just let things slide.
TIA,
Nikom
Robert Santerre on fri 31 dec 99
Nikom, I suggest you call Paul Geil of Geil Kilns (800)887-4345. I recently
discussed this issue with him as I've been considering the purchase of one of
his
fiber kilns. Briefly, he advises against spraying with ITC for the following
reasons:
1. fuel savings is minimal to zero
2. after several firings customers have experienced spalling (ITC chipping off
and
falling onto work - fiber had to be replaced, very unhappy customer
3. the new fiber actually shrinks for the first few firings and this may be
causing the
spalling problem (or customers may not be applying the ITC properly ?)
On the other hand, in my own experience I spray coated a used fiber kiln (small
8 cu ft setting space) with ITC and have experienced none of the spalling
problem.
In fact, I'm quite pleased with the ITC coating. The fiber was beginning to get
brittle
and easily flaked and damaged by the slightest touch before spraying. The ITC
has hardened/stabilized the fiber surface and made it quite abrasion resistant.
I wasn't
keeping good records on fuel consumption so I can't comment on that point (with
the ITC-coated kiln I use about 15 gal of propane per firing). I do cone 10-11
reduction
firing (24 hrs from start to finish, including a 5-6 hr warming step).
You should also call Fritz at ITC and get his take on things. I would guess he
could
put you in contact with some satisfied customers to query about the details of
how
they did their applications.
Hope this helps, Bob
rfsanterre@iquest.net
P.S. I don't work for or have any financial interest in ITC.
//////////////////////////////////////////////////////////////////////
Nikom Chimnok wrote:
> ----------------------------Original message----------------------------
> Hello ITC proponents,
>
> I need some ammo (no, not for shooting capitalists!)
>
> The outfit I work for has just decided to purchase a 5.5 cubic meter
> (roughly 200 cubic feet in Amerikansky) modular ceramic fiber double car
> kiln which will be fired often to cone 6-7. They intend to use it as bare
> fiber, without even a rigidizer. They also want to do some firings with
> terra-cotta sprayed with soda ash, which I suspect would eat the fiber
> really fast.
>
> The contractor has heard of ITC, and doesn't like it. Says it leads
> to cracks between the modules. I suspect this might result from
> misapplication. Anybody have anything to say about this? From my experience,
> I'd give this kiln about a 2 year life expectancy if the fiber is left
> untreated--a terrible waste in a kiln that's going to cost around $25,000.
>
> If anyone, especially an industrial user, could present me with a
> convincing testimonial, I would be most appreciative. I have about six weeks
> left to do battle--wish Alice and crew had E-mail, as I can't start making
> lengthy phone calls to Florida. As you can see, what's been said on Clayart
> over the past couple of years has left me convinced. But I guess I'd also be
> interested to hear from anyone who is not convinced. Life would certainly be
> a lot easier if I just let things slide.
>
> TIA,
> Nikom
Mike Gordon on sun 2 jan 00
Is it possible that the quality of fiber used in Geil kilns is causing
the problem? How many other Geil kiln owners have or haven't had
problems with the use of ITC? Mike
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