Edmund B Burke on wed 31 mar 99
Hi all--I'm new to Clayart but have already enjoyed immensely reading all
the messages each day--a new part of my daily routine! I've particularly
enjoyed all the NCECCA mail--gotta go next year!
I have a question regarding shelves for a high fire gas kiln. I recently
purchased silicon carbide shelves which are slightly warped from a
refractory here in GA. The owner of the company sells a lot of these
shelves to potters particularly in NC and around the South. I decided
they were okay for me (I'm a pottery novice) if they were okay for the
Seagrove potters!
The person with whom I am building the gas kiln talked to a potter in
California who said we should throw them away--said warped shelves would
produce warped pots (which makes sense to me!). She makes a lot of large
platters and bowls about which she is particularly concerned. I think
she has a valid concern, but we just spent $900 for the shelves and
before I throw them out, I wonder how they will work in general--for
smaller pieces, not those with 14" diameters. These shelves are not
severly warped, but some do have a little "contour."
Thanks in advance for any help!
Lynne in Atlanta where SPRING Has Sprung! Azaleas, tulips, dogwoods,
daffodils and all are just about to peak!
Burt Cohen on thu 1 apr 99
Edmund B Burke wrote:
>
> ----------------------------Original message----------------------------
> Hi all--I'm new to Clayart but have already enjoyed immensely reading all
> the messages each day--a new part of my daily routine! I've particularly
> enjoyed all the NCECCA mail--gotta go next year!
>
> I have a question regarding shelves for a high fire gas kiln. I recently
> purchased silicon carbide shelves which are slightly warped from a
> refractory here in GA. The owner of the company sells a lot of these
> shelves to potters particularly in NC and around the South. I decided
> they were okay for me (I'm a pottery novice) if they were okay for the
> Seagrove potters!
>
> The person with whom I am building the gas kiln talked to a potter in
> California who said we should throw them away--said warped shelves would
> produce warped pots (which makes sense to me!). She makes a lot of large
> platters and bowls about which she is particularly concerned. I think
> she has a valid concern, but we just spent $900 for the shelves and
> before I throw them out, I wonder how they will work in general--for
> smaller pieces, not those with 14" diameters. These shelves are not
> severly warped, but some do have a little "contour."
>
> Thanks in advance for any help!
>
> Lynne in Atlanta where SPRING Has Sprung! Azaleas, tulips, dogwoods,
> daffodils and all are just about to peak!
Lynne- You aren't going to have to throw out your used kiln shelves
because they are warped a bit. I have used warped silicon carbide
shelves as do many potters. As you point out smaller pieces are less of
a problem then larger ware. Traditionally in many places, ware is not
fired directly on the shelf, but is put on cookies of stiff refractory
kiln clay which have been dusted in alumina. That way any warpage is
taken care of. How much pottery made from any given clay will change or
warp during a firing is affected by the clay you use-ie how refractory
it is at your firing temperature. Blow some warm air up this way!
Burt Cohen- BC Canada
David Hendley on thu 1 apr 99
Lynne, forgetaboutit.
Any handthrown 14" or larger high-fire stoneware bowl will not be
completely straight and true even if fired on a brand new kiln shelf.
If you make big bowls and platters, save the best shelves for them,
and use the warped ones for everything else.
All, 100%, of my 20+ year-old silicon carbide kiln shelves are cracked,
some in 3 places. About half of them are bowed. These shelves have
a heavy coating of kiln wash for use in my wood kiln, so they are never
flipped over. The funny thing is, half of the shevles are bowed UP
and half are bowed DOWN.
I even use this to my advantage: if, when stacking the kiln, one piece
of pottery is a little tall to fit on a particular shelf, I place it in the
center of the shelf and then use a "bowed-up" shelf for the next layer.
Gives me that extra half-inch of clearance I need!
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
At 01:51 PM 3/31/99 EST, you wrote:
>----------------------------Original message----------------------------
>Hi all--I'm new to Clayart but have already enjoyed immensely reading all
>the messages each day--a new part of my daily routine! I've particularly
>enjoyed all the NCECCA mail--gotta go next year!
>
>I have a question regarding shelves for a high fire gas kiln. I recently
>purchased silicon carbide shelves which are slightly warped from a
>refractory here in GA. The owner of the company sells a lot of these
>shelves to potters particularly in NC and around the South. I decided
>they were okay for me (I'm a pottery novice) if they were okay for the
>Seagrove potters!
>
> The person with whom I am building the gas kiln talked to a potter in
>California who said we should throw them away--said warped shelves would
>produce warped pots (which makes sense to me!). She makes a lot of large
>platters and bowls about which she is particularly concerned. I think
>she has a valid concern, but we just spent $900 for the shelves and
>before I throw them out, I wonder how they will work in general--for
>smaller pieces, not those with 14" diameters. These shelves are not
>severly warped, but some do have a little "contour."
>
>Thanks in advance for any help!
>
>Lynne in Atlanta where SPRING Has Sprung! Azaleas, tulips, dogwoods,
>daffodils and all are just about to peak!
>
Tracy Dotson on fri 2 apr 99
>I wonder how they will work in general--for
smaller pieces, not those with 14" diameters. These shelves are not
severly warped, but some do have a little "contour."
Please do not throw away slightly warped shelves! Most small bottomed pots
will fire fine if you always make sure that each pot does not rock after you
load them. For larger platters and plates just purchase some cheap new 1"
thick clay 12X12" to put under each pot and on the warped shelf. Silicon
shelves will always warp with time and this is a cheap way to solve your
problem. Tracy Dotson Penland NC
amy parker on fri 2 apr 99
> The person with whom I am building the gas kiln talked to a potter in
>California who said we should throw them away--said warped shelves would
>produce warped pots (which makes sense to me!).
Lynne - you did not see the 21 shelves I scraped today!!!! Too bad - they
will be in the kiln by the AM!!! Warped is a matter of perception.
Unless you are going to start making huge platters, don't worry about it!!!
Go look at the shelves for the 10.
amy parker Lithonia, GA
amyp@sd-software.com
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