JRodgers on sat 11 aug 12
Lee, are you suggesting something like a grolleg kaolin?
John Rodgers
On 8/11/2012 8:16 PM, Lee wrote:
> On Sat, Aug 11, 2012 at 2:00 PM, wrote:
>
>>
>> You can expect some discolouration with porcelain by the way - a
>> little grey I think.
>>
>
> You can use molochite in porcelain instead.
>
> Molochite is made by firing raw low-iron kaolin to very high temperatures
> to bring about maximum conversion of the clay crystal to crystalline
> mullite (usually 95%+). The latter has high mechanical stability and
> resistance to thermal shock.
>
> --
> Lee Love in Minneapolis
> http://mingeisota.blogspot.com/
>
> "Ta tIr na n-=F3g ar chul an tI=97tIr dlainn trina ch=E9ile"=97that is,=
"The land
> of eternal youth is behind the house, a beautiful land fluent within
> itself." -- John O'Donohue
>
Carol Holmes-Kerr on sat 11 aug 12
I was told a few years ago that I could add kyanite or grog to stoneware =
=3D
or porcelain to fortify the clay to withstand the thermal shock during =3D
raku firing. =3D20
Unfortunately the person who told me to do this did not tell me how much =
=3D
to add. I usually use Sheba raku clay but I have a bunch of reclaim =3D
that I want to use up and thought this would be an option. =3D20
Carol Holmes-Kerr in Ottawa
John Post on sat 11 aug 12
I picked up a clay body recipe with kyanite from Robert Piepenberg's
book Spirt of Clay.
I don't remember the exact clays he used, but I ended up going with
three different clay bodies using 50# of each and then adding 35# of
48 mesh kyanite. I had a friend fire a life sized clay puffy pillow
in my kiln. It was carved with Celtic knots. The piece was an inch
think or more and it went through the raku firing without a crack.
John Post
Sterling Heights, Michigan
http://www.johnpost.us
Follow me on Twitter
https://twitter.com/UCSArtTeacher
On Aug 11, 2012, at 10:15 AM, Carol Holmes-Kerr wrote:
> I was told a few years ago that I could add kyanite or grog to
> stoneware or porcelain to fortify the clay to withstand the thermal
> shock during raku firing.
> Unfortunately the person who told me to do this did not tell me how
> much to add. I usually use Sheba raku clay but I have a bunch of
> reclaim that I want to use up and thought this would be an option.
>
> Carol Holmes-Kerr in Ottawa
William & Susan Schran User on sat 11 aug 12
On 8/11/12 10:15 AM, "Carol Holmes-Kerr"
wrote:
>I was told a few years ago that I could add kyanite or grog to stoneware
>or porcelain to fortify the clay to withstand the thermal shock during
>raku firing.
>Unfortunately the person who told me to do this did not tell me how much
>to add. I usually use Sheba raku clay but I have a bunch of reclaim that
>I want to use up and thought this would be an option.
I've added up to about 10% kyanite to raku clay for greater thermal shock
resistance.
It's just a guess as I wedge the dry kyanite (or mullite) into moist clay.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
ronroy@CA.INTER.NET on sat 11 aug 12
Hi Carol,
You can certainly add up to 10% and I'm sure even more - to calculate
the dry weight of plastic clay just subtract 30% and base the % of
kyanite on that amount. I think you can get it in 100 and 40 mesh
sizes but the 40 mesh is sharp and difficult to throw with but would
be fine for hand building.
You can expect some discolouration with porcelain by the way - a
little grey I think.
Let me know if you you need more.
RR
Quoting Carol Holmes-Kerr :
> I was told a few years ago that I could add kyanite or grog to
> stoneware or porcelain to fortify the clay to withstand the thermal
> shock during raku firing.
> Unfortunately the person who told me to do this did not tell me how
> much to add. I usually use Sheba raku clay but I have a bunch of
> reclaim that I want to use up and thought this would be an option.
>
> Carol Holmes-Kerr in Ottawa
>
Lee on sat 11 aug 12
On Sat, Aug 11, 2012 at 2:00 PM, wrote:
>
> You can expect some discolouration with porcelain by the way - a
> little grey I think.
>
You can use molochite in porcelain instead.
Molochite is made by firing raw low-iron kaolin to very high temperatures
to bring about maximum conversion of the clay crystal to crystalline
mullite (usually 95%+). The latter has high mechanical stability and
resistance to thermal shock.
--
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
Lee on sun 12 aug 12
On Sat, Aug 11, 2012 at 10:14 PM, JRodgers wrote:
> Lee, are you suggesting something like a grolleg kaolin?
>
> Kaolin Grog is what Molochite is. I am not sure what kaolin is used. =
=3D
I
have a bucket of it Warren MacKenzie gave me. My clay supplier sells it.
I put it in iron clay to make white speckles.
--
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
Steve Mills on sun 12 aug 12
I first came across Kyanite being used by Steven & Susan Kemenyfy in the mi=
d=3D
dle '80s for their large scale Raku Process panels. My memory is that they =
u=3D
sed the same or slightly higher percentages as one would for grog, because=
i=3D
ts particular advantage lies in its ability to give structural strength to =
f=3D
lat (ish) areas.=3D20
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 11 Aug 2012, at 15:15, Carol Holmes-Kerr wr=
o=3D
te:
> I was told a few years ago that I could add kyanite or grog to stoneware =
o=3D
r porcelain to fortify the clay to withstand the thermal shock during raku =
f=3D
iring. =3D20
> Unfortunately the person who told me to do this did not tell me how much =
t=3D
o add. I usually use Sheba raku clay but I have a bunch of reclaim that I =
w=3D
ant to use up and thought this would be an option. =3D20
>=3D20
> Carol Holmes-Kerr in Ottawa
Carol Holmes-Kerr on sun 12 aug 12
Thanks everyone for your input - especially Ron for suggesting subtracting
30% from wet clay weight in order to calculate amount of kyanite to add.
Carol
----- Original Message -----
From: "Steve Mills"
To: "Carol Holmes-Kerr"
Cc:
Sent: Sunday, August 12, 2012 9:09 AM
Subject: Re: Question about kyanite
I first came across Kyanite being used by Steven & Susan Kemenyfy in the
middle '80s for their large scale Raku Process panels. My memory is that
they used the same or slightly higher percentages as one would for grog,
because its particular advantage lies in its ability to give structural
strength to flat (ish) areas.
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 11 Aug 2012, at 15:15, Carol Holmes-Kerr
wrote:
> I was told a few years ago that I could add kyanite or grog to stoneware
> or porcelain to fortify the clay to withstand the thermal shock during
> raku firing.
> Unfortunately the person who told me to do this did not tell me how much
> to add. I usually use Sheba raku clay but I have a bunch of reclaim that
> I want to use up and thought this would be an option.
>
> Carol Holmes-Kerr in Ottawa
-----
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