Wade Blocker on wed 14 mar 01
I have Thorley shelves in my Skutt kiln. The shelf that lines the bottom of
the kiln is blistered and flaking,as well as having a large crack. One of
the shelves I recently purchased has a three inch crack starting at the
edge. I fire from cone 5 to 6, oxidation, no soda or salt firings. I am
very careful to fire up slowly and let the kiln cool off slowly as well. I
have used
Thorley shelves for three decades in various kilns,and never had a problem
with them until now. Mia in ABQ
Kamp, Ryan on wed 14 mar 01
Hello,
I did a cone 10 glaze firing last weekend and opened my Paragon A82-B kiln
to find that my shelves have big blisters all over the place. Looks like a
glassy cobalt coloured mixture is bubbling out. All my pots were fine except
one that had that shelf funk stuck to the bottom. I have done about two
dozen glaze firings since I bought the used kiln with furniture included and
haven't had a problem until now. What would cause this type of thing?
Since I am going to be buying new kiln shelves, what can you all recommend?
Any help with this problem is greatly appreciated.
Thanks!
Ryan Kamp
Cary, NC
Stephen Grimmer on wed 14 mar 01
Ryan,
Are your shelves made from silicon carbide? If so, ask the previous
owner if s/he ever used them in a salt or soda firing.
Steve
--
Stephen Grimmer
Southern Illinois University at Carbondale
> From: "Kamp, Ryan"
> Hello,
>
> I did a cone 10 glaze firing last weekend and opened my Paragon A82-B kiln
> to find that my shelves have big blisters all over the place. Looks like a
> glassy cobalt coloured mixture is bubbling out. All my pots were fine except
> one that had that shelf funk stuck to the bottom. I have done about two
> dozen glaze firings since I bought the used kiln with furniture included and
> haven't had a problem until now. What would cause this type of thing?
>
> Since I am going to be buying new kiln shelves, what can you all recommend?
> Any help with this problem is greatly appreciated.
>
>
> Thanks!
>
> Ryan Kamp
> Cary, NC
Snail Scott on thu 15 mar 01
Does anyone else use your shelves?
When I was a shop tech at a college, people would have
glaze 'problems' all over the shelves (failure to put
shelf scraps under tests, overfiring, mis-mixed glazes,
etc.) and try to hide the fact by cleaning up the shelves
themselves. They would often grind the drips and splatters
down flush or a little below, and refill or paint with
kilnwash. They'd look OK for low-temp/bisque firings, and
maybe even for a few high firings, but the remaining glaze
would eventually seep through the kilnwash.
Grinding to remove ALL the glaze will cure it, but if the
glaze has migrated up, it's probably migrated down as well,
going deeper into the shelf than it was originally. If
it's too deep, suficient grinding will weaken the shelf,
but it might still be usable for bisque/low-fire work.
-Snail
At 12:46 PM 3/14/01 -0500, you wrote:
>
>I did a cone 10 glaze firing last weekend...my shelves
>have big blisters all over the place. Looks like a
>glassy cobalt coloured mixture is bubbling out...
>Ryan Kamp
>Cary, NC
>
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