Angela Davis on sat 30 jun 07
Martha Ann is building a fiber raku kiln and making the ceramic
buttons out of stoneware clay.
She just asked what temp we should fire the buttons to. Regular
bisque or take them to cone 6. I would think there would be no
advantage to fire them higher than bisque temps but have never
read anything about their firing temperatures before. So an
opinion would be apreciated
When I fastened the ceramic blanket in my kiln I used some ceramic
thermocouple wire protector tubes, they are small diameter and about
2 inches long. This has worked great, the wire is fully protected from the
kiln atmosphere and the blanket is held very nicely. Since they are made
for high temperature protection I thought they would hold up better, and
I had plenty on hand. If anyone wants to see a photo of how it looks
just email me.
Watching fireworks over the Homosassa River, happy birthday to US
----- Original Message -----
Sent: Friday, June 29, 2007 7:44 AM
Subject: ceramic fibre fastener source wanted
Tom at Hutchtel.net on mon 2 jul 07
I'm reading this, and particularly sensitive after a cristobalite blowup in
a firing, if making your own buttons from stoneware clays might not be
inviting trouble after a number of firings? Don't know if the cristobalite
can be a problem at cone 6? Ron?
Ron Roy on wed 4 jul 07
I used to think there could be no cristobalite at cone 6 - every cone 6
body I ever ran a dilatometer test on never showed any.
I did find some in some of Standards clays but I still don't know how it
got there - perhaps in a raw material?
I remember measuring some clays that were fired to cone 6 many time but did
not find any under those circumstances.
I did a set of experiments increasing grog in a clay body and that showed
some increase in cristobalite - from the grog.
I would caution against making your own for a high fire kiln unless the mix
is designed to be fired often without generating cristobalite.
I would like to know more about your blowup - what was the mix you used?
>I'm reading this, and particularly sensitive after a cristobalite blowup in
>a firing, if making your own buttons from stoneware clays might not be
>inviting trouble after a number of firings? Don't know if the cristobalite
>can be a problem at cone 6? Ron?
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