ronroy@CA.INTER.NET on mon 6 aug 12
Hi Taylor,
Calcining clay does not result in grit forming - at least I have never
heard of that happening - chuck it - I can't think of how to find out
what it is unless you have it analyzed at a lab.
RR
Quoting Taylor Hendrix :
> Howdy doody,
>
> I have come across some grit in a batch of kiln wash I am making up. I us=
ed
> EPK and silica. I found a bag of "calcined kaolin" on the Art Center shel=
f
> and threw that it to combat some shelling we have with this recipe. When =
we
> made it up and brushed the first shelf, we noticed bad grit, so we sieved
> it and sure enough lots of what appears to be grog. It is fine, graded, a=
nd
> buff in color. Is it possible that however that kaolin was calcined, it
> formed the grit we captured in our sieve? I have never had this happen wh=
en
> I calcine EPK, so I am not sure it is possible.
>
> The simple explanation is that the bag was mislabeled. Shocking, I know.
>
> Thanks folks.
>
> Taylor, in Rockport TX
> wirerabbit1 on Skype (-0600 UTC)
> http://wirerabbit.blogspot.com
> http://wirerabbitpots.blogspot.com
> http://www.flickr.com/photos/wirerabbit/
> https://youtube.com/thewirerabbit
>
Taylor Hendrix on mon 6 aug 12
Howdy doody,
I have come across some grit in a batch of kiln wash I am making up. I used
EPK and silica. I found a bag of "calcined kaolin" on the Art Center shelf
and threw that it to combat some shelling we have with this recipe. When we
made it up and brushed the first shelf, we noticed bad grit, so we sieved
it and sure enough lots of what appears to be grog. It is fine, graded, and
buff in color. Is it possible that however that kaolin was calcined, it
formed the grit we captured in our sieve? I have never had this happen when
I calcine EPK, so I am not sure it is possible.
The simple explanation is that the bag was mislabeled. Shocking, I know.
Thanks folks.
Taylor, in Rockport TX
wirerabbit1 on Skype (-0600 UTC)
http://wirerabbit.blogspot.com
http://wirerabbitpots.blogspot.com
http://www.flickr.com/photos/wirerabbit/
https://youtube.com/thewirerabbit
Steve Mills on tue 7 aug 12
Hi Taylor,=3D20
Another name for Calcined Kaolin or China Clay is Molochite which is a whit=
e=3D
or off-white grog, used in light coloured clay bodies.=3D20
Did/does the bag have a grit size on it I.e. 30/85 or 85/Dust or similar. I=
f=3D
it has, Molochite is what you've got!
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 6 Aug 2012, at 17:49, Taylor Hendrix wrote:
> Howdy doody,
>=3D20
> I have come across some grit in a batch of kiln wash I am making up. I us=
e=3D
d
> EPK and silica. I found a bag of "calcined kaolin" on the Art Center shel=
f=3D
> and threw that it to combat some shelling we have with this recipe. When =
w=3D
e
> made it up and brushed the first shelf, we noticed bad grit, so we sieved
> it and sure enough lots of what appears to be grog. It is fine, graded, a=
n=3D
d
> buff in color. Is it possible that however that kaolin was calcined, it
> formed the grit we captured in our sieve? I have never had this happen wh=
e=3D
n
> I calcine EPK, so I am not sure it is possible.
>=3D20
> The simple explanation is that the bag was mislabeled. Shocking, I know.
>=3D20
> Thanks folks.
>=3D20
> Taylor, in Rockport TX
> wirerabbit1 on Skype (-0600 UTC)
> http://wirerabbit.blogspot.com
> http://wirerabbitpots.blogspot.com
> http://www.flickr.com/photos/wirerabbit/
> https://youtube.com/thewirerabbit
Lee on wed 8 aug 12
On Wed, Aug 8, 2012 at 12:13 PM, Michael Wendt wrote:
My calcine jars often have the entire fill come out as
> one piece even though Helmer melts at cone 32-34!
> Just sayin...
>
My latest tests are trying to approach Mogusa clay, the kind of clay used
in Mino Shino bowls. They don't vitrify at cone 13. The tea masters
liked this, because the unvitrified body makes the same soft sound with the
whisk as in Raku. The Shino and Kuroseto shapes also come from Raku
handbuilt shapes.
I am mixing about half straight helmer with Continental Clay's
Woodfire Porcelain and a little iron clay (enough to get crayola Caucasian
flesh color.) Previous tests have been promising. I do a hakeme
superwhite slip liner to help avoid leakage.
--
Lee Love in Minneapolis
http://mingeisota.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he land
of eternal youth is behind the house, a beautiful land fluent within
itself." -- John O'Donohue
Michael Wendt on wed 8 aug 12
If the calcining was done to a high cone like 10 or higher,
even Helmer sinters slightly, creating harder clumps that
require ball milling to disperse them. Not so for bisque
temperatures.
The reason they form is what is called the superposition
effect in wave theory. Temperature is not a single status
if an object. What we measure is a kind of approximation of mean or
average temperature. The molecular
motion is actually a bell shaped curve and some spots
are remarkably hotter (or cooler) than the average and
they are so randomly. The small amount of flux present
in even the most refractory clays thus reach sintering
temperatures momentarily and create hard nodules
that gradually grow as time passes.
My calcine jars often have the entire fill come out as
one piece even though Helmer melts at cone 32-34!
Just sayin...
Regards,
Michael Wendt
----- Original Message -----
From:
To:
Sent: Monday, August 06, 2012 5:41 PM
Subject: Re: Calcining kaolin
> Hi Taylor,
>
> Calcining clay does not result in grit forming - at least I have never
> heard of that happening - chuck it - I can't think of how to find out
> what it is unless you have it analyzed at a lab.
>
> RR
>
>
> Quoting Taylor Hendrix :
>
>> Howdy doody,
>>
>> I have come across some grit in a batch of kiln wash I am making up. I
>> used
>> EPK and silica. I found a bag of "calcined kaolin" on the Art Center
>> shelf
>> and threw that it to combat some shelling we have with this recipe. When
>> we
>> made it up and brushed the first shelf, we noticed bad grit, so we sieve=
d
>> it and sure enough lots of what appears to be grog. It is fine, graded,
>> and
>> buff in color. Is it possible that however that kaolin was calcined, it
>> formed the grit we captured in our sieve? I have never had this happen
>> when
>> I calcine EPK, so I am not sure it is possible.
>>
>> The simple explanation is that the bag was mislabeled. Shocking, I know.
>>
>> Thanks folks.
>>
>> Taylor, in Rockport TX
>> wirerabbit1 on Skype (-0600 UTC)
>> http://wirerabbit.blogspot.com
>> http://wirerabbitpots.blogspot.com
>> http://www.flickr.com/photos/wirerabbit/
>> https://youtube.com/thewirerabbit
>>
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