Suchman ceramics on sat 14 nov 09
I'm looking for a ^6 stony matte recipe for both ox & reduction. I couldn'=
t
find one in mc6g. semi-matte only.
I have this ^10 recipe from a school I once attended:
Custer feldspar..... 49
Dolomite.............. 22
Whiting.................. 4
Kaolin...................25
This recipe was pretty cool. (While disturbing to hear with a knife scrapin=
g
against it) For the outside of ware it was cool as it was kinda reactive i=
n
that it would pick up atmospheric copper and receive lavender/red blushes
that I found appealing. When over fired it would have semi-glossy streaks
through it which gave it a bone-like quality.
I'm now working at ^6 reduction and oxidation at times as well. I wonder i=
f
a neph sy sub for the custer would bring it down to ^6 or not. Any
suggestions?
Do any of you have a stony matte recipe for ^6 that you'd like to share? I
would certainly appreciate it.
Thanks,
Eric
--
-e-in-o'side-
pagan by nature
>http://www.flickr.com/photos/42169721@N04/
Chaeli Sullivan on sun 15 nov 09
Am not sure about this but: =3DA0since the Dolomite in that percentage will=
p=3D
reserve the stony matte, wouldn't switching Gerstley Borate for the Custer =
=3D
feldspar=3DA0do a better job of bringing the ^10 recipe down to a ^6?
Chae
--- On Sat, 11/14/09, Suchman ceramics wrote:
From: Suchman ceramics
Subject: ^6 Stony Matte
To: Clayart@LSV.CERAMICS.ORG
Date: Saturday, November 14, 2009, 7:10 PM
I'm looking for a ^6 stony matte recipe for both ox & reduction.=3DA0 I cou=
ld=3D
n't
find one in mc6g. semi-matte only.
I have this ^10 recipe from a school I once attended:
Custer feldspar..... 49
Dolomite.............. 22
Whiting.................. 4
Kaolin...................25
This recipe was pretty cool. (While disturbing to hear with a knife scrapin=
=3D
g
against it)=3DA0 For the outside of ware it was cool as it was kinda reacti=
ve=3D
in
that it would pick up atmospheric copper and receive lavender/red blushes
that I found appealing.=3DA0 When over fired it would have semi-glossy stre=
ak=3D
s
through it which gave it a bone-like quality.
I'm now working at ^6 reduction and oxidation at times as well.=3DA0 I wond=
er=3D
if
a neph sy sub for the custer would bring it down to ^6 or not.=3DA0 Any
suggestions?
Do any of you have a stony matte recipe for ^6 that you'd like to share?=3D=
A0=3D
I
would certainly appreciate it.
Thanks,
=3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 =3DA0 Eric
--
-e-in-o'side-
pagan by nature
>http://www.flickr.com/photos/42169721@N04/
=3D0A=3D0A=3D0A
Richard White on sun 15 nov 09
Eric, that one is going to be tough. I put your ^10 recipe into a glaze
calculation program (insert plug for Glazemaster here...) and its unity
calculation is similar to one called VCT that we used and loved in the
school studio up though last year when we were firing the gas kiln to ^10=
=3D
.
It is an alkaline earth matte, high in magnesium and calcium, and with a =
=3D
low
silica:alumina ratio. For better or worse, high Ca and Mg simply need mor=
=3D
e
heat to melt. We are now firing at ^6 and this is one glaze we haven't be=
=3D
en
able to replicate to our satisfaction, despite suggestions from some of t=
=3D
he
best glaze experts out there (John and Roy, you know who you are ;) ) Add=
=3D
ing
other fluxes, e.g., the usual boron that often brings a glaze down to the=
=3D
mid-range, doesn't help much. The surface isn't as matte as we'd like and=
=3D
the fit is a little off. (It seems to need more silica, but that would ta=
=3D
ke
us further away from the matte...) We are still trying, but haven't gotte=
=3D
n
there yet.
dw
ivor & olive lewis on mon 16 nov 09
Dear Eric,
I think there are two basic forms of Matt Glaze.
One form has an over abundance of highly refractory ingredients that never
entirely dissolve in the ingredient that is expected to melt and act as a
solvent for materials that will not generally fuse at the firing temperatur=
e
of your kiln.
In the other form of matt glaze, an aggressive solvent flux dissolves all o=
f
the high melting point ingredients to give a saturated vitreous solution at
the kiln firing temperature. These will recrystallise to give an opaque,
matt surface if the kiln can be cooled at a rate slower than the Critical
Cooling Rate. If cooled faster than the CCR the glaze retains glassy
qualities; smooth, reflective, transparent.
Yes, I would expect the glaze to mature at a lower temperature if Neph
Syenite were substituted for Custer's Felspar, though this might introduce =
a
fit problem and induce crazing. Perhaps substituting a proportion of frit
for some of the Kaolin and Dolomite might be a better option
Eva Gallagher on mon 16 nov 09
Hi - here is a stoney white that we have used at cone 8 (benefits from a
slow cool.) in oxidation - get great red rusts with the iron underglaze. Ro=
n
Roy reformulated it for me for cone 6 - though never got around to testing
it much as at that time we finally got our gas kiln. Here is the recipe
below
Bozak Stony White - Cone 8 ox
Neph Sye 48
Dolomite 27
Ball Clay 6
Silica 17
Zinc ox 3
Add Tin ox - 3% - Zirco does not work - need tin for orange rusts.
Bento - 2%
Usually I would add 1/2% iron to take away white starkness.
Great over iron underglaze
Red Iron ox - 2 part
Ball clay 2 part
Feldspar potash 1 part
Use thickness of 3% milk
Also white is great if spray highlights of Rutile/ Gerst Bor 1:1 by parts o=
n
top. Or if want darker highlights use iron, rut, gerst bor in 1:1:1 parts=
.
Other colours - Beige - 2% red iron ox
Rusty - 6% Iron, 6% rutile - get orange, even some pinks
Green - 3% Copper carb, 3% Nickel carb -
Dark brown - 10 -15%
All were on brown clay - but if you just spray a very thin coating of iron
underglaze - like a very thin transparent water color wash first on white
clay it will give similar results as brown clay. Or brush it on and then
wipe it off, leaving just colour in the pores.
I will send athe Ron Roy reformulated Bozak Stoney White once I find it as
it is not in my regular data base.
Eva Gallagher
Deep River, Ontario
http://stevenhilljourneyworkshopjuly2008.blogspot.com/
----- Original Message -----
From: "Suchman ceramics"
To:
Sent: Saturday, November 14, 2009 9:10 PM
Subject: ^6 Stony Matte
> I'm looking for a ^6 stony matte recipe for both ox & reduction. I
> couldn't
> find one in mc6g. semi-matte only.
> I have this ^10 recipe from a school I once attended:
>
> Custer feldspar..... 49
> Dolomite.............. 22
> Whiting.................. 4
> Kaolin...................25
>
> This recipe was pretty cool. (While disturbing to hear with a knife
> scraping
> against it) For the outside of ware it was cool as it was kinda reactive
> in
> that it would pick up atmospheric copper and receive lavender/red blushes
> that I found appealing. When over fired it would have semi-glossy streak=
s
> through it which gave it a bone-like quality.
> I'm now working at ^6 reduction and oxidation at times as well. I wonder
> if
> a neph sy sub for the custer would bring it down to ^6 or not. Any
> suggestions?
> Do any of you have a stony matte recipe for ^6 that you'd like to share?
> I
> would certainly appreciate it.
> Thanks,
> Eric
> --
> -e-in-o'side-
> pagan by nature
>>http://www.flickr.com/photos/42169721@N04/
>
>
John Hesselberth on mon 16 nov 09
Hi Eric,
While the MC6Gs are aimed at the range of semimattes through glossies, =3D
you can get pretty dry mattes from some of them by slowing the cooling =3D
down even more. Check out:
http://frogpondpottery.com/nceca2004/p18.html and
http://frogpondpottery.com/nceca2004/p19.html
for examples. If those still aren't dry enough, you will probably have =3D
to go to alumina mattes which are not nearly as stable as the glazes in =3D
MC6Gs. Depending on your application that may or may not be a good idea.
Regards,
John
Steve Slatin on mon 16 nov 09
It's too rainy for yard work today, so I'm going to
take a stab at this question.
The basic question here is that old bugaboo -- how
do you alter a recipe that works at one firing to
be substantially similar at another? Some methods
work, others don't. Also, because your firing
(at ^10) is liable to be different in various ways
from your firing at ^6, overcoming the various
differences is likely to be difficult. Not impossible!
If you have the time to investigate various
possibilities, you may find, for example, that
a few percent of zinc will do the trick, because
the usual problems with using zinc to alter a ^10
glaze (that it's an opacifier and muddies clear
colors) would probably not be an issue with a
"stony matte" glaze. Alternatively, you could
increase the sodium level (substituting Nephelene
Syenite for some or all of the feldspar) to lower
the melting temperature, and then 'correct' for
the tendency to increased crackling by adding some
low CTE/COE materials (like using Ferro 3249 to
sub for your magnesium source; it adds a bit more
boron than you'd probably like but it'll melt at
1900 F, so it's a good carrier of the Mg).
This testing, until you find something you really
like, may take months. And, it may not be successful.
Alternatively, you could start with a high-calcium,
high-magnesium matte glaze that works at ^6 -- I'd
recommend MCM 1 or 2 from Michael Bailey's excellent
"Glazes Cone 6" and see if that's sufficiently close
to the result you want at your personal ^6 firing.
It requires --
Soda Feldspar 42
China Clay 4
Bentonite 2
Dolomite 22
Whiting 3
Zinc Oxide 5
Flint or Quartz 22
One for a man, two for a horse. Free advice,
and worth every penny.
Steve Slatin --
May Luk on tue 17 nov 09
I have not read anywhere that potters have successfully lower the
temperature from a cone 10 to a cone 6 and get the same glaze. Everybody
still ask and dream of an easy way. eek!
I have tested this glaze and it's very nice with a slow cool cycle. Not
stoney, just dolomity matte. I have also done a Currie Grid with these base
materials to know that: more clay, more stoney. Once again, change of Al:Si
ratio change the color appearance of the glaze. You've been warned! "-)
May
Brooklyn NY
P.S. Hello Steve!!
> [...]
> Alternatively, you could start with a high-calcium,
> high-magnesium matte glaze that works at ^6 -- I'd
> recommend MCM 1 or 2 from Michael Bailey's excellent
> "Glazes Cone 6" and see if that's sufficiently close
> to the result you want at your personal ^6 firing.
>
> It requires --
>
> Soda Feldspar 42
> China Clay 4
> Bentonite 2
> Dolomite 22
> Whiting 3
> Zinc Oxide 5
> Flint or Quartz 22
>
> One for a man, two for a horse. Free advice,
> and worth every penny.
>
>
> Steve Slatin --
>
--
http://twitter.com/MayLuk
http://www.flickr.com/groups/handmade_mugs/
Neal on tue 17 nov 09
The base glaze recipe I posted earlier this year might
work. It was:
Dolomite 19.0
Gerstley Borate 12.0
Kona F4 Feldspar 37.0
Silica 32.0
Zinc Oxide, calcined 7.0
I am using two versions--one that's lavender with 0.5
cobalt carbonate and 0.2 copper carbonate added and
another that is light green with 2.0 copper carbonate
added.
I am thinking about leaving out the colorants the next
time I make a batch to do some tests with different
ones.
Neal O'B.
Raleigh, N.C.
Neon-Cat on wed 18 nov 09
Hi Eric and all,
Here are a few more recipes to play with. They're from Mimi Obstler's
"Out of the Earth into the Fire".
1. Albany Yellow (a yellow satin-matt)
Cone 5-6 Oxidation
Albany Slip 42.25%
Nephelline Syenite 22.75
Gerstley Borate 17.50
Dolomite 17.50
Tin Oxide 3.00
For a mustard-colored stony matt omit the Nephelline Syenite.
2. un-named experiments
Cone 5-6 Oxidation
Yellow-white stony glaze surface
F-4 Feldspar 70%
Whiting- 30
Yellow-white, dry, stony surface
F-4 Feldspar 60%
Whiting 40
3. Katherine Choy Glaze with additional whiting
Dry, stony yellow surface
Cone 5-6 Oxidation
Nephelline Syenite 53.9%
Whiting 21.7
Lithium Carbonate 4.7
Zinc oxide 10.3
EPK Kaolin 17.9
Flint 1.5
4. Katherine Choy Glaze with additional EPK
Dry, stony whitish surface
Cone 5-6 Oxidation
Nephelline Syenite 53.9%
Whiting 11.7
Lithium Carbonate 4.7
Zinc oxide 10.3
EPK Kaolin 27.9
Flint 1.5
5. White Matt - a stony matt
Cone 5-6 Oxidation
Nephelline Syenite 54.10%
Whiting 17.37
Zinc Oxide 9.40
Flint 5.20
EPK Kaolin 13.90
6. Vivika Heino - white, stony-matt
Cone 5-6 Oxidation
Nephelline Syenite 54.55%
Whiting 17.5
EPK Kaolin 14.0
Flint 5.2
Zinc Oxide 9.5
7. Ron's White Matt #5 - white, stony-matt
Cone 5-6 Oxidation
Nephelline Syenite 55%
Whiting 15
EPK Kaolin 16
Zinc Oxide 14
For an Albant Slip substitute try:
(source TCC-NW, TX)
Red Art 7314
Nepheline Syenite 501
EPK 359
Dolomite 686
Whiting 606
Flint 534
Marian
www.neon-cat.com
Suchman ceramics on sat 21 nov 09
Many thanks all!
-Eric
-e-in-o'side-
pagan by nature
>http://www.flickr.com/photos/42169721@N04/
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