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the best kiln shelves-period

updated thu 17 jan 08


Mark Cortright on wed 16 jan 08

After testing advancers -(45) 12x 24 for 150 cone 11 firings I can say these simply are super. Yes
you can thermo crack them -yes you can blow them to smitherines if they are wet-just like pots.
They break when dropped or bumped hard just like other refractories. The thing is they stay FLAT
always and they do not Soak up glaze ever-think about that glaze does not soak into them and
chips right off -never do you grind into a glaze soaked shelve.Glaze simply does not go into the
That cannot be said for any of the knock offs and I have tried them as well. Heres the results the
first ones from china warped and cracked then the next batch they had cut stright lines into each
side -helped with the cracking but they warp to-also glaze soaks into both kinds-Yes they are
much cheaper and a bit thicker-you get what you pay for.I'm a high fire porcelain Studio potter
who has all the aliments of over 30 years of loading a car kiln weekly. The advancers wiegh the
least 12x24=9# and work the best. I just wish I had known about them 30 years ago instead of 7
years ago just for my backs sake. My English hi alumina dry pressed 12x24 1inchers wiegh 33#
each-they are retired to the salt kiln for life.
Mark Cortright

mark Cortright on wed 16 jan 08

I had an e-mail about washing these -here is my reply
I use neither wadding or waxing- for cone 11 reduction loads ( in salt kilns I use hydrated wading
)I washed my shelves with my own homemade wash
1/2 alumina hydrate 1/4 calcined EPK 1/4 EPK mix thin like heavy cream- roll on with wide paint
roller on sun heated shelves-dry in sun- use a knife to cut/clean edges of wash when dry -bisque
slowly with pots on them next bisque fire. This wash is easy to remove and stays put-that is does
not get freeborne and ruin other pots.
When ready to buy talk to Donna at Smith sharp-firebrick supply-they usuall will have a lower
price when you purchase 10 or more so I always bought them in at least 10 lots-Tell Donna I sent
you-she knows me. Ph 866-545-6743

mark Cortright on wed 16 jan 08

One thing I did not cover and will is they will crack if you try to quick cool them. If your chimmy
leaks air they can crack -the lower shelve near the leak or flue is most vunerable. You need to
have tight kiln that does not keep weeping air when its shut off.That is the chimmey does not
keep pulling air in past the bag walls and indroducing cold air to chamber this will aslo cuase
cracking.Do not try to quik cool these-use lesser type shelves for that. Also these will pay for
themselves in short time due to the saving of space and the ware you will fire in that space. I know
of 2 other full time potters who use them like me and love them. Mark cortright