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cone 6 glaze--speckling with granular illmenite

updated fri 12 apr 02

 

Dave Finkelnburg on thu 4 apr 02


Elinor,
If you test granular illmenite, which makes nice speckles, you will find
it settles very quickly in most glazes. The illmenite is about twice as
heavy per unit volume as other glaze ingredients, and larger particles
besides, so you need to stir the glaze frequently to get an even application
of the illmenite.
Good glazing!
Dave Finkelnburg

Valerie Hawkins on thu 4 apr 02


I've tried granular ilmenite to color a glaze and all I got was granular
ilmenite. It didn't melt at cone 6. Are there certain glaze ingredients
that will promote melting? I was using Hanson's 5X20

Valerie

-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Dave Finkelnburg
Sent: Thursday, April 04, 2002 7:21 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Cone 6 glaze--speckling with granular illmenite


Elinor,
If you test granular illmenite, which makes nice speckles, you will find
it settles very quickly in most glazes. The illmenite is about twice as
heavy per unit volume as other glaze ingredients, and larger particles
besides, so you need to stir the glaze frequently to get an even application
of the illmenite.
Good glazing!
Dave Finkelnburg

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Carol Tripp on thu 4 apr 02


Valerie,
Try adding 4% rutile plus the granular illmenite - stir all the time as Dave
F says - and you will get a speckled cream with the 5x20. Don't, however,
try to layer anything with this glaze because I have found the 5x20 always
crawls.
Regards,
Carol

Valerie wrote:
>>I've tried granular ilmenite to color a glaze and all I got was granular
>ilmenite. It didn't melt at cone 6. Are there certain glaze ingredients
>that will promote melting? I was using Hanson's 5X20

>


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Snail Scott on thu 4 apr 02


At 08:35 AM 4/4/02 -0500, you wrote:
>I've tried granular ilmenite to color a glaze and all I got was granular
>ilmenite. It didn't melt at cone 6. Are there certain glaze ingredients
>that will promote melting? I was using Hanson's 5X20.


Granular ilmenite won't melt - the particle size is
too big. That's why it's used for speckles. For color,
you would need to use powdered (milled) ilmenite.
This is not a readily available material.

Ilmenite may be considered a close cousin of rutile,
being also composed of titanium and iron, but it has
more iron than rutile. (The iron content of rutile is
variable, but always less than ilmenite as far as I
know.) Most people, when looking to add iron and
titanium to a glaze for color, choose rutile for the
purpose, as it can be readily obtained in powdered
form. If you want more iron than rutile will provide,
just add a little RIO to the recipe.

-Snail

Paul Lewing on thu 4 apr 02


Elinor, ilmenite will typically give you dark brown specks. I believe your
original post asked for a source of tan specks. For that I'd try granular
rutile. It will sink to the bottom just like Dave F. pointed out ilmenite
will.
Paul Lewing, Seattle

Valerie Hawkins on fri 5 apr 02


-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Snail Scott
Sent: Thursday, April 04, 2002 12:06 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Cone 6 glaze--speckling with granular illmenite


At 08:35 AM 4/4/02 -0500, you wrote:
>I've tried granular ilmenite to color a glaze and all I got was granular
>ilmenite. It didn't melt at cone 6. Are there certain glaze ingredients
>that will promote melting? I was using Hanson's 5X20.


Granular ilmenite won't melt - the particle size is
too big. That's why it's used for speckles. For color,
you would need to use powdered (milled) ilmenite.
This is not a readily available material.

Ilmenite may be considered a close cousin of rutile,
being also composed of titanium and iron, but it has
more iron than rutile. (The iron content of rutile is
variable, but always less than ilmenite as far as I
know.) Most people, when looking to add iron and
titanium to a glaze for color, choose rutile for the
purpose, as it can be readily obtained in powdered
form. If you want more iron than rutile will provide,
just add a little RIO to the recipe.

-Snail

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__
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Valerie Hawkins on fri 5 apr 02


Snail,

One of the many disavantages of being self-taught. I often don't know
exactly what to expect. I just couldn't couldn't see why anyone would want
the effect I got with the granular ilmenite. I was like grains of metalic
sand embedded in the glaze.
I wasn't expecting the ilmenite to color the glaze. But I was expecting a
colored flecking or freckling as I would get from granulated manganese.

Valerie



-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Snail Scott
Sent: Thursday, April 04, 2002 12:06 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Cone 6 glaze--speckling with granular illmenite


At 08:35 AM 4/4/02 -0500, you wrote:
>I've tried granular ilmenite to color a glaze and all I got was granular
>ilmenite. It didn't melt at cone 6. Are there certain glaze ingredients
>that will promote melting? I was using Hanson's 5X20.


Granular ilmenite won't melt - the particle size is
too big. That's why it's used for speckles. For color,
you would need to use powdered (milled) ilmenite.
This is not a readily available material.

Ilmenite may be considered a close cousin of rutile,
being also composed of titanium and iron, but it has
more iron than rutile. (The iron content of rutile is
variable, but always less than ilmenite as far as I
know.) Most people, when looking to add iron and
titanium to a glaze for color, choose rutile for the
purpose, as it can be readily obtained in powdered
form. If you want more iron than rutile will provide,
just add a little RIO to the recipe.

-Snail

____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org

You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/

Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.

Earl Brunner on sat 6 apr 02


Some granular ilmenite that I have purchased had larger particle sizes
than others. The finer stuff is working great; the courser stuff leaves
the rough sandy texture you describe. We use it in a cone 6 "Oatmeal"
recipe that the studio has had for at least 6 years. When using the
coarser stuff I screen it first.

Earl Brunner
mailto:bruec@anv.net
http://coyote.accessnv.com/bruec

I just couldn't see why anyone would want
the effect I got with the granular ilmenite. I was like grains of
metalic
sand embedded in the glaze.
I wasn't expecting the ilmenite to color the glaze. But I was
expecting a
colored flecking or freckling as I would get from granulated manganese.

Valerie

iandol on sun 7 apr 02


Dear Valerie Hawkins,

Snail can correct me if I am wrong about this, but I thought the idea of =
adding coarse materials to give speckles was done when you are kneading =
your clay. Then, when the glaze which covers the clay, starts to bond to =
the clay it reveals the granular materials which bleed into the glaze as =
they dissolve. These coarser materials are not put into the glaze.

Best regards,

Ivor Lewis.

vince pitelka on mon 8 apr 02


Ivor wrote:
"Snail can correct me if I am wrong about this, but I thought the idea of
adding coarse materials to give speckles was done when you are kneading your
clay. Then, when the glaze which covers the clay, starts to bond to the clay
it reveals the granular materials which bleed into the glaze as they
dissolve. These coarser materials are not put into the glaze."

Ivor -
Coarser materials intended to produce speckling are often added to
commercial lowfire glazes intended for brushing, because the gums keep the
coarse materials in suspension. They are occasionally added to regular
studio-mixed ceramic glazes, but those glazes need to be re-mixed very
actively right before dipping or pouring the glaze in order to bring the
coarse materials up into suspension, and even then the effects appear in
higher concentration in "rivulets" where the glaze flows off the pot.
Best wishes -
- Vince

Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/

Snail Scott on mon 8 apr 02


At 03:25 PM 4/7/02 +0930, Ivor wrote:
>...I thought the idea of adding coarse materials to give speckles was done
when you are kneading your clay...which bleed into the glaze as they
dissolve. These coarser materials are not put into the glaze.


Adding speckles to the clay is probably the most
popular method, since it simulates the effect of a
naturally-spotted hand-dug clay. (and there's no
concern about settling.) Commercial clay bodies are
also available with speckles already added.

Many people do like to add speckles to their glaze
instead, but the result is a very different effect
from a speckled body bleeding through the glaze.

I think people got used to the speckled-glaze look
because manufacturers of 'pseudo-handmade' tableware
used speckly glazes (starting back around 1970 or
so,) to play on the handmade pottery craze of the day.
Probably easier for them than using speckled clay in
their previously-established manufacturing process.

Of course, you can use speckly glazes for reasons
other than simulating handmade stoneware. (Especially
if you ARE making handmade stoneware!) ;) It's a
perfectly legitimate design choice, and actually, the
manufacuters' logic applies here, too. If your glaze
is speckly, you can make all your ware out of one
consistent clay body and get your variations through
your choice of glaze rather than adjusting to a new
clay body in order to achieve specks on just some of
your ware. However, as several people have observed,
it doesn't work well with all glazes.

It doesn't look quite the same as a spotted clay,
but it can still be an interesting effect in its own
right, whatever your reasons for choosing it.

-Snail

Steve Mills on tue 9 apr 02


In message , iandol writes
>Dear Valerie Hawkins,
>
>Snail can correct me if I am wrong about this, but I thought the idea of =
>=3D
>adding coarse materials to give speckles was done when you are kneading =3D
>your clay. Then, when the glaze which covers the clay, starts to bond to =
>=3D
>the clay it reveals the granular materials which bleed into the glaze as =
>=3D
>they dissolve. These coarser materials are not put into the glaze.
>
>Best regards,
>
>Ivor Lewis.

But they can be; We manufacture our own range of Brush-on glazes, aimed
originally at the Education based customers. In the early stages we
considered adding speckles to the range, there being a wide range (and I
mean WIDE!) of speckles available to us from one of our material
suppliers. We didn't do it in the end, we just have a range of bright
coloured glazes which the Schools love.

Steve
Bath
UK
--
Steve Mills
Bath
UK

iandol on wed 10 apr 02


Dear Vince,=20

I appreciate the information you give but from memory the original =
posting commented on the degree to which the granular material protruded =
through the glaze to give a rather coarse surface finish.

If, as you suggest, the glaze is brushed on thickly then the granules =
may settle down and remain under the surface of the glaze.

Best regards,

Ivor.

vince pitelka on thu 11 apr 02


Ivor wrote:
"I appreciate the information you give but from memory the original posting
commented on the degree to which the granular material protruded through the
glaze to give a rather coarse surface finish.
If, as you suggest, the glaze is brushed on thickly then the granules may
settle down and remain under the surface of the glaze.

Ivor -
Sorry, I guess I missed that part. The granular materials I am familiar
with in commercial low-fire glazes are generally used to create spotted
effects rather than to create texture. In other words, they melt.

In high-fire glazes some people use granular rutile or granular ilmenite to
create a speckled effect, and aside from the problem with the granular
materials settling out quickly, it does in fact create nice speckling, with
no surface texture.
Best wishes -
- Vince

Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/