Hank Ray on wed 23 sep 98
hello ... glaze gods and such....
i think this is interesting... i have glaze for a cone 10 rutile blue...
custer spar....30
dolomite........15.8
whiting...........11.1
epk................16.80
flint................26.30
rutile..............8
and it comes out in all it's wacky rutile blue kinda way... but it is runny..
so you have to put it on thin.....
"so i tried...."
Custer spar.....60
dolomite.........10
epk.................20
talc................10
rutile ..............8
and it came out a creamy yellow type color ,,,, totally different........
so can anyone tell me what makes a rutile blue....and what went wrong...
thanks
peter coates
city art center....okc ok
www.cityartscenter.com
Helllll@aol.com
Donn Buchfinck on thu 24 sep 98
just use logic
you took an ingredient out to begin with
the whiting
plus the blue comes from the interaction of the iron in the clay body that is
pulled out through body reduction, durring that time iron is reduced by the
action of putting more gas in the kiln than there is oxegen to combust it,
the heat breaks the fuel down and the hot fuel goes looking for oxegen. that
is why when you pull a peep plug the flame jumps out at you the supper hot
gasses are looking for oxegen to burn, well that supper hot fuel gets the
oxegen from where ever it can, and one of the places is the pottery pieces
themselves. so the iron oxide becomes black iron, a very powerfull flux and
some of the iron moves to the surface of the pot, thus giving iron spots,
there the iron interacts with the glaze, mixing with the rutile and creating a
different glaze where ever the iron spot is, giving you blue.
the iron reduction action is why when you reduce a salt kiln and get these
real chocalate brown pots from light stoneware bodies, the reason is that if
the clay has some iron in it the iron comes to the surface and the action of
the soda and/or salt desolves the iron into a thin layer over the pot
creating a brown pot.
so some of you will say, but I get rutile blue from an electric kiln, and I
would return that I have seen that, and the person who is doing it, is using a
high iron clay body or slip.
there is a place between the glaze and the clay body that is a combination of
both, where the glaze eats into the clay disolving some of the stuff out of
it and creating something that is not the glaze or the clay, this affects the
way the glaze looks, thus this is why when you put a glaze on one clay then a
different one they look different. because it is the interation of the clay
and the glaze that gives you a particular effect.
use an iron wash on the bisque ware before you dip it into the rutile glaze,
it will give you some great effects.
1/2 gram bentonite
1/2 gram borax
1 gram iron
this is the porportion for the stain
mix it with hot water in a blender
you can thin it out
once again forgive me for my meager grammar and spelling
Andrew Buck on thu 24 sep 98
Peter,
The rutile glaze I use comes out kind of pinkish pastel on porcelain but
when I put it on my red stoneware clay it comes out with the blues. Try
adding a smidge of red iron oxide to the glaze or try putting it on a red
clay.
On Wed, 23 Sep 1998, Peter Coats wrote:
> ----------------------------Original message----------------------------
> so can anyone tell me what makes a rutile blue
David Hendley on fri 25 sep 98
Pete,
I disagree with the answers you've gotten regarding rutile blue.
I'm always hesitant to answer glaze questions to the Clayart list
because I don't always know what's going on at the molecular level,
but I do know, from experience, what works.
So, I'll be waiting for the theoritcal chemists to correct me.
Rutile blue requires a well-balanced glossy glaze,
something smack-dab in the middle of the limit formulas.
Plenty of silica.
There's no need for it to be runny.
I am not 100% positive about this, but I think you could
take any good celadon glaze that you have, add the right
amount of rutile, and get rutile blue.
By the way, I also think that same base glaze would be a good
start for a tenmoku glaze (add more iron) or a copper red
glaze (delete the iron and add copper and tin).
If a glaze is low in silica, like the typical matt glaze,
rutile will turn it orange or yellow, not blue.
I didn't run your second recipe through a glaze program, but
it looks like a typical matt glaze that is silica-deficient.
Another reason for not getting blue is a too-thin application
of glaze.
Finally, I think it is the titanium, not the iron that is of primary
importance in a rutile blue glaze. I have proven this to
myself with some blue glazes made with titanium and used on
white porcelainous stoneware claybodies.
The iron just modifies or amplifies the color.
Here's an old reliable rutile blue that I've used for decades:
#51 Rutile Blue, from Big Creek Pottery, Davenport, California, 1973
Feldspar (I've used all kinds, they all worked).....357
Flint.....436
Whiting.....159
Kaolin.....137
Red Iron Oxide.....50
Rutile.....50
Don't eat too much cotton candy at the Oklahoma State Fair.
David Hendley, glaze god and such,
Maydelle, Texas
At 11:01 AM 9/23/98 EDT, you wrote:
>----------------------------Original message----------------------------
>hello ... glaze gods and such....
>
>i think this is interesting... i have glaze for a cone 10 rutile blue...
>custer spar....30
>dolomite........15.8
>whiting...........11.1
>epk................16.80
>flint................26.30
>rutile..............8
>
>and it comes out in all it's wacky rutile blue kinda way... but it is runny..
>so you have to put it on thin.....
>
>"so i tried...."
>
>Custer spar.....60
>dolomite.........10
>epk.................20
>talc................10
>rutile ..............8
>
>and it came out a creamy yellow type color ,,,, totally different........
>so can anyone tell me what makes a rutile blue....and what went wrong...
>
>thanks
>peter coates
>city art center....okc ok
>www.cityartscenter.com
>Helllll@aol.com
>
Ron Roy on sat 26 sep 98
Hi Peter,
Well I just went through my complete library and came up with precious
little on rutile blues. I have calculated your original recipe and compared
it with your new one - perhaps there are some clues there.
Original rutile Blue (runny) Probably a durable glaze at cone 10r although
a little short of silica.
-----------------
CUSTER SPAR......... 30.00
DOLOMITE............ 15.80
WHITING............. 11.10
EPK................. 16.80
SILICA.............. 26.30
RUTIL............... 8.00
----------
108.00
FORMULA & ANALYSIS
------------------
*CaO........ .60 12.00%
MnO2.......
*MgO........ .25 3.58%
*K2O........ .10 3.32%
*Na2O....... .05 .99%
Fe2O3...... .02 .96%
TIO2....... .28 7.94%
AL2O3...... .34 12.38%
SiO2....... 2.77 58.80%
P2O5....... .00 .02%
RATIO 8.07
EXPAN 523.67
WEIGHT 282.51
Your revision which is a tan at cone 10r - not the same type of glaze at
all - oversupplied with alumina and magnesia and we would expect a tan
colour from this type.
-----------------
CUSTER SPAR......... 60.00 55.56%
DOLOMITE............ 10.00 9.26%
EPK................. 20.00 18.52%
TALC................ 10.00 9.26%
RUTIL............... 8.00 7.41%
----------
108.00
FORMULA & ANALYSIS
------------------
*CaO........ .25 4.20%
MnO2....... .00 .02%
*MgO........ .43 5.12%
*K2O........ .22 6.15%
*Na2O....... .10 1.87%
Fe2O3...... .02 .93%
TIO2....... .31 7.44%
AL2O3...... .59 17.89%
SiO2....... 3.16 56.37%
P2O5....... .00 .02%
RATIO 5.36
EXPAN 550.90
WEIGHT 336.40
I suggest you simply add more clay (EPK) to your original 1% at a time till
the running stops enough to use it.
I suspect your rutile has a lot more iron than the analysis that I use - I
can only surmise that is the extra flux that would make this glaze run
badly at cone 10r.
>----------------------------Original message----------------------------
>i think this is interesting... i have glaze for a cone 10 rutile blue...
>custer spar....30
>dolomite........15.8
>whiting...........11.1
>epk................16.80
>flint................26.30
>rutile..............8
>
>and it comes out in all it's wacky rutile blue kinda way... but it is runny..
>so you have to put it on thin.....
>
>"so i tried...."
>
>Custer spar.....60
>dolomite.........10
>epk.................20
>talc................10
>rutile ..............8
>
>and it came out a creamy yellow type color ,,,, totally different........
>so can anyone tell me what makes a rutile blue....and what went wrong...
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
Tom Wirt on sun 27 sep 98
>
>so some of you will say, but I get rutile blue from an electric kiln, and I
>would return that I have seen that, and the person who is doing it, is using a
>high iron clay body or slip.
>
Donn,
I don't know why rutile forms blue, but my experience is that the more iron
in/under the glaze, the greener it goes. We HAVE to use a white stoneware body
to get a good rutile. We get it in both electric and gas firing. If we over
reduce, the blue goes turquoisy.
Be glad to send you some samples if you email me your address. Betsy (who does
all our glazing and firing) is the queen of rutile blue.
Tom Wirt
Clay Coyote Pottery
17614 240th St.
Hutchinson, MN 55350
320-587-2599
claypot@hutchtel.net
Milton Markey on fri 2 oct 98
David,
What is the cone of this glaze? Do you fire this in an "oxy" or "redux"
atmosphere?
Thanks!
Milton MiltonsLin@AOL.COM
---------------------
In a message dated 98-09-25 19:42:59 EDT, you write:
> 51 Rutile Blue, from Big Creek Pottery, Davenport, California, 1973
>
> Feldspar (I've used all kinds, they all worked).....357
> Flint.....436
> Whiting.....159
> Kaolin.....137
> Red Iron Oxide.....50
> Rutile.....50
>
> Don't eat too much cotton candy at the Oklahoma State Fair.
> David Hendley, glaze god and such,
> Maydelle, Texas
>
>
>
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