Lis Allison on sun 4 oct 09
Hello Clayarters,
A friend is having some interesting results with an ash glaze that gives
nice reduction-type effects at cone 6. Only trouble is, on the parts of
the pots that have no slip under the glaze, it crazes badly. She tells me
the glaze was on a bit thick in places, but her test tiles on bare clay
also craze. Can anything be done about this while keeping the nice runny
ash look? Here is the recipe:
K's Ash Glaze
Ash 33
Neph. Sye . 28
Talc 6.5
Alberta slip clay 18
EPK 3.5
Flint 5
Anhydrous Borax 6
Iron oxide 2%
Rutile 4%
the Rutile Engobe: Rutile 50
Gert. Bor. 50
Or should she just accept the crazing as part of the 'look'?
Lis
--
Elisabeth Allison
Pine Ridge Studio
www.Pine-Ridge-Studio.blogspot.com
Jess McKenzie on sun 4 oct 09
Lis Allison
wrote, in part ...
A friend is having some interesting results with an ash glaze
that gives nice reduction-type effects at cone 6. Only trouble
is, on the parts of the pots that have no slip under the
glaze, it crazes badly. She tells me the glaze was on a bit
thick in places, but her test tiles on bare clay also craze.
...
Lis, we are presently deep into the Hesselberth/Roy book,
"Mastering Cone 6 Glazes." It may take a bit of study, but we
are certain your friend will find the answer there.
~joan and jess in Sequim, WA
Earl Brunner on sun 4 oct 09
Probably not.=3DA0 Ash by it's nature=3DA0tends to=3DA0put a degree of vari=
ablene=3D
ss into a glaze.=3DA0 Additionally, ash, soda and salt firing all tend to h=
av=3D
e the ash, soda, and salt interacting with the other=3DA0minerals in both t=
he=3D
clay and any glazes in ways that are hard to=3DA0control and many of them =
cr=3D
aze.=3DA0=3DA0If you do manage to control it, you will most likely lose the=
ver=3D
y=3DA0characteristics of the glaze that you like.=3D0A=3DA0Earl Brunner=3D0=
ALas Veg=3D
as, NV =3D0A=3D0A=3D0A=3D0A=3D0A________________________________=3D0AFrom: =
Lis Allison =3D
=3D0ATo: Clayart@LSV.CERAMICS.ORG=3D0ASent: Sun, October=
4, =3D
2009 5:30:37 AM=3D0ASubject: Ash glaze - crazing=3D0A=3D0AHello Clayarters,=
=3D0A=3D0A=3D
A friend is having some interesting results with an ash glaze that gives=3D=
0A=3D
nice reduction-type effects at cone 6. Only trouble is, on the parts of=3D0=
At=3D
he pots that have no slip under the glaze, it crazes badly. She tells me=3D=
0A=3D
the glaze was on a bit thick in places, but her test tiles on bare clay=3D0=
Aa=3D
lso craze. Can anything be done about this while keeping the nice runny=3D0=
Aa=3D
sh look? Here is the recipe:=3D0A=3D0AK's Ash Glaze=3D0A=3D0AAsh=3DA0 =3DA0=
=3DA0 =3DA0 =3DA0=3D
=3DA0 =3DA0 =3DA0 =3DA0 33=3D0ANeph. Sye .=3DA0 =3DA0 28=3D0ATalc=3DA0 =3D=
A0 =3DA0 =3DA0 =3DA0 =3DA0 =3D
=3DA0 =3DA0 =3DA0 6.5=3D0AAlberta slip clay 18=3D0AEPK=3DA0 =3DA0 =3DA0 =3D=
A0 =3DA0 =3DA0 =3DA0 =3DA0=3D
3.5=3D0AFlint=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 5=3D0AA=
nhydrous Borax 6=3D0AIro=3D
n oxide=3DA0 =3DA0 2%=3D0ARutile=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 4%=3D0A=
=3D0Athe Rutile Engobe=3D
:=3DA0 =3DA0 Rutile=3DA0 50=3D0A=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =
=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0=3D
=3DA0 =3DA0 =3DA0 Gert. Bor. 50=3D0A=3D0AOr should she just accept the cra=
zing as pa=3D
rt of the 'look'?=3D0A=3D0ALis=3D0A--=3D0AElisabeth Allison=3D0APine Ridge =
Studio=3D0Aw=3D
ww.Pine-Ridge-Studio.blogspot.com=3D0A
Steve Slatin on sun 4 oct 09
Lis --
Your friend needs to specify what kind of ash she's
using -- ashes vary greatly depending on what's in them.
Washed ashes also differ greatly from unwashed ashes.
Some ashes have CTE/COE on the order of 15;=3D20
She's got a lot of Nepheline Syenite in there, though,
and Neph Sye has a high CTE/COE. (About 9.)
Well behaved glazes, in my experience, run about 6-7.
Many ash glazes craze (salt fired ware often crazes, also).
I'd say it's part of 'the look'.
Steve Slatin --=3D20
--- On Sun, 10/4/09, Lis Allison wrote:
>=3D20
> A friend is having some interesting results with an ash
> glaze that gives
> nice reduction-type effects at cone 6. Only trouble is, on
> the parts of
> the pots that have no slip under the glaze, it crazes
> badly. She tells me
> the glaze was on a bit thick in places, but her test tiles
> on bare clay
> also craze. Can anything be done about this while keeping
> the nice runny
> ash look? Here is the recipe:
>=3D20
> K's Ash Glaze
>=3D20
> Ash=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0
> =3DA0 33
> Neph. Sye .=3DA0 =3DA0=3DA0=3DA028
> Talc=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0
> =3DA0 =3DA0 6.5
> Alberta slip clay 18
> EPK=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0
> 3.5
> Flint=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0
> =3DA0 =3DA0=3DA0=3DA05
> Anhydrous Bor28ax 6
> Iron oxide=3DA0 =3DA0=3DA0=3DA02%
> Rutile=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 4%
>=3D20
> the Rutile Engobe:=3DA0 =3DA0 Rutile=3DA0 50
> =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0
> =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0
> Gert. Bor. 50
>=3D20
> Or should she just accept the crazing as part of the
> 'look'?
>=3D20
> Lis=3D0A=3D0A=3D0A
Craig Martell on tue 6 oct 09
Josh was saying:
>My general experience is that ash glazes which don't either craze or run
>are boring and you might as well not use the ash ...
Hello Ash Glaze Enthusiasts:
Well, OK, Enthusiasts only if the glaze is a crazing runner.
Ash glazes that run are considered "high flux" glazes. When the fluxes are
at this level the alumina and silica will be lower than recommended for a
durable glaze. This doesn't mean that they are not safe to use on
functional pots. If there are no potentially toxic materials in the glaze
the potter will not have to worry about safety issues with the ware. But
the end result is that the glazes will run and have a nice textured look
and will break color and have some very enticing effects along with crazing=
.
I make some of my ash glazes with as much silica and alumina as they will
stand and still do some stringing. I then use them on non functional pots
or place the glaze on the outside of a functional piece. I will also use
them on functional surfaces that don't get a lot of wear with use. Bowl
and plate rims for instance.
As for the non running ash glazes being a boring use of ash my take
is: Sure that's going to be the case with some folks but there are a lot
of non running glazes using ash that are really stunning. I've run several
Ian Currie grids of ash glazes and have come up with three that I use which
are non runners and are very stable and functional. An ash celadon, a
chun, and a Nuka. I like the chun more than any of my running ash
glazes. I guess there's a stereotypical idea that ash glazes are all
running, stringy looking glazes. These are easy to designate visually but
the others are not and you have to give them a closer look. The definition
of a Nuka glaze is a high silica ash glaze. They are very lovely over dark
slips. You can make Nukas without ash too but the Nukas with ash are more
interesting to me personally.
regards, Craig Martell Hopewell, Oregon
| |
|
