Steve Dalton on mon 5 aug 02
Greetings,
While working late at night with my assistant Igor and conducting secret
experiments in my lab...I have concocted a new blue glaze! This is not a
2x4 across the face blue...strong cobalt blue that will make you sick after
the first load, but a soft, almost pale blue.
I used Mamo as the base and added .5% cobalt carbonate. With the addition
of cobalt, the violet Mamo makes when thick is increased but not to the
stage where one will be sick of it in a short time.
Mamo Light Blue ^10 reduction
Custer 47.61
EPK 23.75
Dolomite 19.06
Whiting 4.79
Albany Slip 4.79
Add
Cobalt Carb .5
I even played around adding rutile to the mix. With .5% rutile and .5%
cobalt, the glaze becomes a blue grey.
--
Steve Dalton
Clear Creek Pottery
Snohomish, Wa
sdpotter@gte.net
Earl Brunner on mon 5 aug 02
I want to talk to Igor, perhaps we can pry some more secrets out of his
unsuspecting and trusting mind..........
Steve Dalton wrote:
> Greetings,
>
> While working late at night with my assistant Igor and conducting secret
> experiments in my lab...I have concocted a new blue glaze! This is not a
> 2x4 across the face blue...strong cobalt blue that will make you sick after
> the first load, but a soft, almost pale blue.
>
> I used Mamo as the base and added .5% cobalt carbonate. With the addition
> of cobalt, the violet Mamo makes when thick is increased but not to the
> stage where one will be sick of it in a short time.
>
> Mamo Light Blue ^10 reduction
> Custer 47.61
> EPK 23.75
> Dolomite 19.06
> Whiting 4.79
> Albany Slip 4.79
>
> Add
> Cobalt Carb .5
>
> I even played around adding rutile to the mix. With .5% rutile and .5%
> cobalt, the glaze becomes a blue grey.
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
mudduck on fri 18 jun 10
Hi All
I'm trying to develop a cone 10 mild reduction glaze that is a kind of =3D
medium blue, maybe like a light royal.
I'm using a Temmoku base and changing the oxides.
The base is
custer 450
silica 270
whiting 170
EPK 40
OM-4 70
These are the colorants that were added
cobalt ox. 15
chrome 7
copper ox .5
This recipe came out to dark almost a navy. I cut the cobalt back to 10 =3D
instead of 15, still a little to dark and was starting to go a little =3D
green. Should I have cut all the oxides an equal amount?? Does anyone =3D
have suggestions of oxide combo's that might give me the color I'm =3D
shooting for???
When I make this glaze as a Temmoku using 10% RIO It's nice and hard on =3D
the pot. When It's made with the cobalt, chrome and copper the glaze is =3D
real dust and rubs off easily. So should I add some CMC to make the =3D
glaze harder when on the pot???
Can you suggest a colorant combination that will come close to a light =3D
royal blue??
Thanks!!
Gene
mudduck@mudduckpottery.net
www.mudduckpottery.net
Edouard Bastarache on fri 18 jun 10
My best blue
http://www.flickr.com/photos/potier/22895817/
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://blogsalbertbastarache.blogspot.com/
http://cerampeintures.blogspot.com/
http://perso.wanadoo.fr/smart2000/index.htm
David Hendley on fri 18 jun 10
Gene, you need to run a line blend or tri-axial blend of colorants
to develop your new glaze. That will allow you to get exactly
what you want.
As for your recipe, I don't know why you would be using
chrome or copper oxides in hopes of a royal blue glaze.
Chrome oxide makes green - get it out of there. In a
tenmoku-type base, copper can make copper red, which,
combined with the cobalt, can make purple. I would get rid
of it, as undependable and unnecessary.
Just shooting from the hip, I would suggest additions of cobalt
carbonate, Ultrox, and iron oxide to make a good blue.
Try the cobalt from .5 to 1%. Just a little iron oxide will warm
up the color, try about .2 to .5%. Unless you want a watery,
celadon- type glaze, Ultrox, at about 2 to 5%, can make the
blue deeper and richer.
I think a better blue could result if some of the whiting was
replaced with dolomite, like 1/4 to 1/3 of the whiting.
Magnesium makes cobalt go towards purple, which, used
in small quantities, can make a richer looking royal blue.
My final suggestion is to not try to reinvent the wheel - just
look up blue glazes in John Britt's High-Fire Glazes book,
pick a few to try, and tweak them to suit your desires and
tastes using line blends. If you don't have the book, it is
well worth the almost give-away price for which it can be
purchased.
David Hendley
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
From: "mudduck"
To:
Sent: Friday, June 18, 2010 12:36 PM
Subject: new blue glaze
Hi All
I'm trying to develop a cone 10 mild reduction glaze that is a kind of
medium blue, maybe like a light royal.
I'm using a Temmoku base and changing the oxides.
The base is
custer 450
silica 270
whiting 170
EPK 40
OM-4 70
These are the colorants that were added
cobalt ox. 15
chrome 7
copper ox .5
June on fri 18 jun 10
I get a royal blue in my celadon base using 1% cobalt oxide and 5% Alberta=
slip. If you don't have Alberta slip you can try adding 1 to 2% red iron o=
xide. It will modify/soften the cobalt a bit. If you want it lighter than t=
hat then drop the cobalt oxide to 0.75 % and still add the 1-2% iron oxide.=
I'd made one batch with 0.5 cobalt oxide and iron, and another with 1% cob=
alt oxide and 1% iron and then then wet mix equal parts of it to get a thi=
rd version which would be 0.75% cobalt and 1% iron, or 5% Alberta, dependin=
g on which material you use - the slip or iron oxide.
Regards,
June
http://www.shambhalapottery.com
http://www.shambhalapottery.blogspot.com
http://groups.yahoo.com/group/sodasaltfiring/
http://saltandsodafiring.ning.com/
Regards,
June
http://www.shambhalapottery.com
http://www.shambhalapottery.blogspot.com
http://groups.yahoo.com/group/sodasaltfiring/
http://saltandsodafiring.ning.com/
Jun 18, 2010 01:47:33 PM, mudduck@mudduckpottery.net wrote:
>Hi All
>
>I'm trying to develop a cone 10 mild reduction glaze that is a kind of med=
ium
>blue, maybe like a light royal.
>
>I'm using a Temmoku base and changing the oxides.
>
>The base is
>
>custer 450
>silica 270
>whiting 170
>EPK 40
>OM-4 70
>
>These are the colorants that were added
>cobalt ox. 15
>chrome 7
>copper ox .5
>
>This recipe came out to dark almost a navy. I cut the cobalt back to 10 in=
stead
>of 15, still a little to dark and was starting to go a little green. Shoul=
d I have
>cut all the oxides an equal amount?? Does anyone have suggestions of oxide=
combo's
>that might give me the color I'm shooting for???
>
>When I make this glaze as a Temmoku using 10% RIO It's nice and hard on
>the pot. When It's made with the cobalt, chrome and copper the glaze is re=
al
>dust and rubs off easily. So should I add some CMC to make the glaze harde=
r when
>on the pot???
>
>Can you suggest a colorant combination that will come close to a light roy=
al
>blue??
>
>Thanks!!
>Gene
>mudduck@mudduckpottery.net
>www.mudduckpottery.net
>
David Finkelnburg on sat 19 jun 10
Gene,
With absolute respect for my good friend David Hendley, I would
absolutely not pick some glazes out of a book and go to work on testing the=
m
until you have tested your perfectly workable base glaze for which you are
just seeking the right blend of colorants. Also, David's suggestion to use
Ultrox will give an opaque blue. There are different opinions over what
constitutes "royal blue" and if you want a blue that tends to sky blue then
the Ultrox/Zircopax route David suggests will help get you there. If you
want a darker blue, though, a translucent glaze with no opacifier and just
cobalt will work.
Cobalt, chrome, copper and iron makes black. Cobalt and chrome will ten=
d
to teal as the balance reaches more chrome than cobalt. You may find it
best to follow David's suggestion for the line blend by losing the chrome
and then testing lesser amounts of cobalt. 1.5% cobalt is a lot, will make
a pretty dark blue. 0.7% chrome is a lot, too, by itself will make a nice
John Deere green! The small amount of copper in your recipe probably won't
be detectable. If you haven't already done so, and you may have because
you've been working at this quite a while, in your line blend test cobalt
alone all the way down to 0.25% to see the effect.
You are using a very nice, stable cone 10 base glaze. With the
0.7Cao:0.3 KNaO ratio, though, cobalt will tend to be dark (tends to a
Noxema blue) if you use much of it. If you need a brighter blue you will
have to go to a base with a higher percentage of alkali fluxes and to
control expansion that may mean using some lithium source in place of some
of the whiting. Isn't glaze testing fun?
Good potting!
Dave Finkelnburg
http://www.mattanddavesclays.com
-----------------------------
Date: Fri, 18 Jun 2010 13:36:51 -0400
From: mudduck
Subject: new blue glaze
Hi All
I'm trying to develop a cone 10 mild reduction glaze that is a kind of =3D
medium blue, maybe like a light royal.
I'm using a Temmoku base and changing the oxides.
The base is
custer 450
silica 270
whiting 170
EPK 40
OM-4 70
These are the colorants that were added
cobalt ox. 15
chrome 7
copper ox .5
This recipe came out to dark almost a navy. I cut the cobalt back to 10 =3D
instead of 15, still a little to dark and was starting to go a little =3D
green. Should I have cut all the oxides an equal amount?? Does anyone =3D
have suggestions of oxide combo's that might give me the color I'm =3D
shooting for???
When I make this glaze as a Temmoku using 10% RIO It's nice and hard on =3D
the pot. When It's made with the cobalt, chrome and copper the glaze is =3D
real dust and rubs off easily. So should I add some CMC to make the =3D
glaze harder when on the pot???
Can you suggest a colorant combination that will come close to a light =3D
royal blue??
Thanks!!
Gene
mudduck@mudduckpottery.net
www.mudduckpottery.net
Victoria E. Hamilton on sat 19 jun 10
Hello Edouard -
Lovely blue. Does it work at ^10? If so, do you have a photo that shows
what it looks like?
Thanks so much.
Vicki Hamilton
Seattle, WA
-----Original Message-----
From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Edouard
Bastarache
Sent: Friday, June 18, 2010 1:58 PM
To: Clayart@LSV.CERAMICS.ORG
Subject: Re: new blue glaze
My best blue
http://www.flickr.com/photos/potier/22895817/
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://blogsalbertbastarache.blogspot.com/
http://cerampeintures.blogspot.com/
http://perso.wanadoo.fr/smart2000/index.htm
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