Larry Kruzan on sat 6 jan 07
Hi Bill,=20
I have been using the "Chinese" shelves for a year and have never kiln
washed them and have never had a problem. Even with a certain copper =
red
that runs off a pot if cone 10 bends at all. In my last firing a
crystalline glazed pot and setter tray cracked through the bottom - as a
result there was a LOT of run off all over the shelf, I just lifted the
whole mess off the shelf and into the trash. Shelf just like new.
When I bought my shelves a year ago my budget would have only allowed me =
to
buy 10 advancers whereas I could buy the 24 Chinese shelves I really =
needed.
Since I only fire to cone 10 reduction or cone 6 ox so if they are good =
for
2480 F it's no big deal. =20
Porosity of my clay concerns me but since I don't leave my shelves
unprotected in the elements I sleep well. Perhaps if I did wash the =
shelves
they would absorb the moisture from the wash and blow up during the =
firing,
but since I follow the instructions from Paul Geil about not kiln =
washing
then this should not matter. =20
They have been through 22 firings with only one mishap - I dropped a pot
onto a shelf from about 18" - broke it. My fault, I'm clumsy sometimes. =
A
1 inch silicon carbide might have survived - not sure about advancers.
I will continue to test these every 2 to 3 weeks, and let you know how =
they
perform.
Larry Kruzan
Lost Creek Pottery
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of William & =
Susan
Schran User
Sent: Saturday, January 06, 2007 3:15 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: [CLAYART] Nitride bonded silicon carbide kiln shelves advise
Had an individual send me a message asking about the Chinese =
manufactured
nitride bonded silicon carbide kilns shelves and how they compare to
Advancers.
A spec sheet for the material was included with the message and this is =
the
information:
Advancers have a firing limit of 2642=B0F and a porosity of <1%.
By way of comparison, regular silicon carbide shelves have a porosity of
15%.
The information provided to me shows a limit temperature of 2480=B0F and =
a
porosity of 16%! An analysis of the make-up of the shelves indicate 75%
silicon carbide and 20% silicon nitride.
There is certainly a great price difference.
A 12 x 24 Advancer is about $120 and a weight of about 9lbs, while the =
other
shelf is about $50 and weighs 11lbs.
I would advise folks purchasing the Chinese manufactured nitride bonded
shelves to get them for weight & space saving reasons. I would also =
highly
advise folks to use kiln wash on these shelves, because I don't think =
glaze
drips will pop off as with Advancers. If you go to kilnshelf.com you can =
get
contact information about a kiln wash made specifically for the nitride
bonded shleves. I don't know the composition of this wash, but I might
assume a alumina/zirconium mix.
If anyone has experience with the less expensive nitride bonded shelves,
please post to this forum and advise if my assumptions are correct.
--=20
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
_________________________________________________________________________=
___
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
William & Susan Schran User on sat 6 jan 07
Had an individual send me a message asking about the Chinese manufactured
nitride bonded silicon carbide kilns shelves and how they compare to
Advancers.
A spec sheet for the material was included with the message and this is the
information:
Advancers have a firing limit of 2642=B0F and a porosity of <1%.
By way of comparison, regular silicon carbide shelves have a porosity of
15%.
The information provided to me shows a limit temperature of 2480=B0F and a
porosity of 16%! An analysis of the make-up of the shelves indicate 75%
silicon carbide and 20% silicon nitride.
There is certainly a great price difference.
A 12 x 24 Advancer is about $120 and a weight of about 9lbs, while the othe=
r
shelf is about $50 and weighs 11lbs.
I would advise folks purchasing the Chinese manufactured nitride bonded
shelves to get them for weight & space saving reasons. I would also highly
advise folks to use kiln wash on these shelves, because I don't think glaze
drips will pop off as with Advancers. If you go to kilnshelf.com you can ge=
t
contact information about a kiln wash made specifically for the nitride
bonded shleves. I don't know the composition of this wash, but I might
assume a alumina/zirconium mix.
If anyone has experience with the less expensive nitride bonded shelves,
please post to this forum and advise if my assumptions are correct.
--=20
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
Tara Mooney on sun 7 jan 07
May I add, is one better than the other to use in humid environment?
Tara
On Jan 6, 2007, at 4:14 PM, William & Susan Schran User wrote:
> Had an individual send me a message asking about the Chinese =20
> manufactured
> nitride bonded silicon carbide kilns shelves and how they compare to
> Advancers.
>
> A spec sheet for the material was included with the message and this =20=
> is the
> information:
>
> Advancers have a firing limit of 2642=B0F and a porosity of <1%.
>
> By way of comparison, regular silicon carbide shelves have a porosity =20=
> of
> 15%.
>
> The information provided to me shows a limit temperature of 2480=B0F =
and =20
> a
> porosity of 16%! An analysis of the make-up of the shelves indicate =
75%
> silicon carbide and 20% silicon nitride.
>
> There is certainly a great price difference.
> A 12 x 24 Advancer is about $120 and a weight of about 9lbs, while the =
=20
> other
> shelf is about $50 and weighs 11lbs.
>
> I would advise folks purchasing the Chinese manufactured nitride =
bonded
> shelves to get them for weight & space saving reasons. I would also =20=
> highly
> advise folks to use kiln wash on these shelves, because I don't think =20=
> glaze
> drips will pop off as with Advancers. If you go to kilnshelf.com you =20=
> can get
> contact information about a kiln wash made specifically for the =
nitride
> bonded shleves. I don't know the composition of this wash, but I might
> assume a alumina/zirconium mix.
>
> If anyone has experience with the less expensive nitride bonded =20
> shelves,
> please post to this forum and advise if my assumptions are correct.
>
>
> -- =20
> William "Bill" Schran
> wschran@cox.net
> wschran@nvcc.edu
> http://www.creativecreekartisans.com
>
> =
_______________________________________________________________________=20=
> _______
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at =20
> melpots@pclink.com.
Kathi LeSueur on sun 7 jan 07
Larry Kruzan wrote:
>Hi Bill,
>
>I have been using the "Chinese" shelves for a year and have never kiln
>washed them and have never had a problem. Even with a certain copper red
>that runs off a pot if cone 10 bends at all. In my last firing a
>crystalline glazed pot and setter tray cracked through the bottom - as a
>result there was a LOT of run off all over the shelf, I just lifted the
>whole mess off the shelf and into the trash. Shelf just like new.>>
>
Since I'm planning to replace my shelves soon and am consider Advancers
of other like them, I'm wondering about the firing cycle people use. My
kiln heats up rapidly (I have to hold it back). I'm at 1500 in four
hours. Is a rapid heat climb a problem with these shelves? What would be
recommend as a good fring cycle.?
Thanks,
Kathi
>
>
>
>
Ingeborg on sun 7 jan 07
Larry,
Do you flip your shelves each time you fire or is that not necessary?
Ingeborg
3058 Stringfellow Road
P.O. Box 510
Saint James City, FL 33956
http://www.thepottersworkshop.com
Larry Kruzan on mon 8 jan 07
Hi Kathi,
My average rate of climb is 300 degrees per hour - but - because I use a
downdraft design kiln I too experience very rapid heat gain in the first
couple hours. I'll check my firing log when I go to the studio the next
time but I know I am well over 1000 in the first three hours unless I only
start one burner. Scared me silly on the first firing when I saw 1500 in
three hours - then I remembered the pyrometer is measuring air temp. not
heat work. I will get a copy of my last firing log and post it to you.
Thanks,
Larry Kruzan
Lost Creek Potery
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Kathi LeSueur
Sent: Sunday, January 07, 2007 12:53 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: [CLAYART] Nitride bonded silicon carbide kiln shelves advise
Larry Kruzan wrote:
>Hi Bill,
>
>I have been using the "Chinese" shelves for a year and have never kiln
>washed them and have never had a problem. Even with a certain copper red
>that runs off a pot if cone 10 bends at all. In my last firing a
>crystalline glazed pot and setter tray cracked through the bottom - as a
>result there was a LOT of run off all over the shelf, I just lifted the
>whole mess off the shelf and into the trash. Shelf just like new.>>
>
Since I'm planning to replace my shelves soon and am consider Advancers
of other like them, I'm wondering about the firing cycle people use. My
kiln heats up rapidly (I have to hold it back). I'm at 1500 in four
hours. Is a rapid heat climb a problem with these shelves? What would be
recommend as a good fring cycle.?
Thanks,
Kathi
>
>
>
>
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
William & Susan Schran User on mon 8 jan 07
On 1/7/07 1:53 PM, "Kathi LeSueur" wrote:
> Since I'm planning to replace my shelves soon and am consider Advancers
> of other like them, I'm wondering about the firing cycle people use. My
> kiln heats up rapidly (I have to hold it back). I'm at 1500 in four
> hours. Is a rapid heat climb a problem with these shelves?
The gas kiln we fire with Advancer shelves fires up rather fast. 800=B0F in
the first hour, up to 1500=B0F in 4 hours or less. No problems.
--=20
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
David Woof on tue 9 jan 07
Larry, Kathi, a word of caution and perhaps clarification re pyrometers,
heat work and extreemly rapid fireing. Yes, your pyrometer is indicating
kiln atmosphere temp. but what should be your concern is what that heat is
doing to your kiln and kiln furniture by way of thermal shock. Your shelves
must adjust to the changes in heat by expansion and contraction within the
shelf body. the shelf edges absorb heat faster than the center, and
further, where ever you have support posts and pots sitting, especially
large pots and platters, the heat absorbsion is shared by the ware as well
as the shelf and the even distribution and subsequent even expansion and
contraction of shelves and ware are adversely effected by fast fireing. You
can apply this in reverse to extreemly rapid cooling as well. There is not
enough time for the heat to more uniformly penetrate or vacate all areas.
This is where and many times why shelves and large platters crack.
Best wishes, hope this adds assist to your success.
David
_________________________________
_________________________________
David Woof Studio
Clarkdale, Arizona
Ph. 928-821-3747 Fax. 866-881-3461
________________________________
________________________________
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