Lili Krakowski on tue 7 nov 06
Dear Kathryn,
About your glaze. There is nothing plastic in it to keep it in suspension.
Think
Dead Sea. You have seen pictures of people floating effortlessly in it.
Reason:
all that salt keeps them afloat. That--in a loose analogy--is what plastic
materials,
clay, bentonite, commercial additives do in the glaze slop.
So for one I'd add 2-3 % bentonite.
And I have used granular Ilmenite in glazes. If the glaze is suspended
properly,the
Ilmenite stays afloat. Do not recall if the specks it creates stay "pebbly"
in the surface, or melt into teensy blotches.
Then I ran your glaze through GlazeMaster(TM) and fell off my chair. (No
serious
injury, thank you.)
You say it is runny at c.5-6...but to my amazement your alumina is even over
the
c.10-12 limits Rhodes gives, your Silica just a tidge below his highest
figure of 5.
LiO2 .229
Na2O .198
K2O .075
CaO .498
Al2O3 .596
B2O3 .436
SiO2 4.824
And COE 60.91-- most likely to shiver.
And here is my question for Ron. As I was lying on the floor I looked at
your
Fat White recipe. (No, I got that off a Ron message on ClayArt, do not know
if it is/is not in book)
If I copied it correctly:
EPK 13.5
Frit 3124 5
Custer spar 354
Dolomite 19.5
Talc 1
Flint 26
And
Na2O .073
K2O .125
MgO .351
CaO .451
Al2O3 .370
B2O3 .032
SiO2 3.146
COE 66.26
Aha! Here is a glaze we know works and ALSO is solidly beyond the "limits"
for c.6.
What am I missing? I have used glazes beyond the "limits" but my glazes
tend
to have a goodly amount of B2O3 which
I have assumed has a mitigating effect. The Fat White has very little.
And by the way. Like many people who have dealt with proofs etc. I can read
upside down with ease. So of course I read my medical charts whenever the
MD is out of the room. On one chart I read: the patient is a
"well-nourished Caucasian
woman..." Now you see how much more honest potters are: Fat White would
have been just as accurate, and less pretentious!
Lili Krakowski
Be of good courage
Donna Kat on wed 8 nov 06
On Tue, 7 Nov 2006 08:09:39 -0500, Lili Krakowski
wrote:
>Dear Kathryn,
>
>About your glaze. There is nothing plastic in it to keep it in
suspension.
>Think
>Dead Sea. You have seen pictures of people floating effortlessly in it.
>Reason:
>all that salt keeps them afloat. That--in a loose analogy--is what
plastic
>materials,
>clay, bentonite, commercial additives do in the glaze slop.
>So for one I'd add 2-3 % bentonite.
>
>And I have used granular Ilmenite in glazes. If the glaze is suspended
>properly,the
>Ilmenite stays afloat. Do not recall if the specks it creates
stay "pebbly"
>in the surface, or melt into teensy blotches.
>
>
>Then I ran your glaze through GlazeMaster(TM) and fell off my chair. (No
>serious
>injury, thank you.)
>
>You say it is runny at c.5-6...but to my amazement your alumina is even
over
>the
> c.10-12 limits Rhodes gives, your Silica just a tidge below his highest
>figure of 5.
>
>LiO2 .229
>Na2O .198
>K2O .075
>CaO .498
>Al2O3 .596
>B2O3 .436
>SiO2 4.824
>
>And COE 60.91-- most likely to shiver.
>
>And here is my question for Ron. As I was lying on the floor I looked at
>your
>Fat White recipe. (No, I got that off a Ron message on ClayArt, do not
know
>if it is/is not in book)
>
>
>If I copied it correctly:
>
>EPK 13.5
>Frit 3124 5
>Custer spar 354
>Dolomite 19.5
>Talc 1
>Flint 26
>
>And
>
>Na2O .073
>K2O .125
>MgO .351
>CaO .451
>Al2O3 .370
>B2O3 .032
>SiO2 3.146
>
>COE 66.26
>
>Aha! Here is a glaze we know works and ALSO is solidly beyond
the "limits"
>for c.6.
>
>What am I missing? I have used glazes beyond the "limits" but my glazes
>tend
>to have a goodly amount of B2O3 which
>I have assumed has a mitigating effect. The Fat White has very little.
>
>And by the way. Like many people who have dealt with proofs etc. I can
read
>upside down with ease. So of course I read my medical charts whenever the
>MD is out of the room. On one chart I read: the patient is a
>"well-nourished Caucasian
>woman..." Now you see how much more honest potters are: Fat White would
>have been just as accurate, and less pretentious!
>
>
>
>Lili Krakowski
>Be of good courage
>
Thanks for the chuckle from another "well-nourished Caucasian (through I'm
certain their is Asian in my background).
By the by, I believe you meant to type Custer 35.0 rather that Custer 354.
Donna Kat
sacredclay on wed 8 nov 06
Lili, Thank you. This is the kind of info I was looking for.When you
say it's over the alumina limits of c.10-12, did you mean cone 10-12?
Is possible that the MaO made it a little runny? It didn't quite run,
just kind of pooled down a little bit. Surface is not smooth, there's
alot of tiny tiny craters. On the one with both rutile and gran. Ille.,
I can't tell which one is causing the specks, as the clay is also
recycled with speckeled brownstone.Apparently, the temp is maturing
enough, as the gr. ill. is melted completely and not rouch surface.I
think I'm looking to see if I can create an almond smooth matte glaze
with surface variation.I know rutile will do that.I'm just using this
glaze as a test to see what I can come up with. If there's too much
alumina, then I need to find another glaze to play around with. I'm
probably going to use Roy/John glazes and play with that, but I want to
see how far I can go with this one. Thanks for all of your comments.
This is what I was looking for. Will let you know how others turn out.
Timothy Joko-Veltman on wed 8 nov 06
On 11/8/06, sacredclay wrote:
> Lili, Thank you. This is the kind of info I was looking for.When you
> say it's over the alumina limits of c.10-12, did you mean cone 10-12?
> Is possible that the MaO made it a little runny? It didn't quite run,
No, she's referring to the general "rule" that 0.3-0.4 alumina in a
cone 10-12 glaze is all that is needed to keep it from over-melting.
It is the high lithium and boron content that really flux this glaze.
Tim
Ron Roy on wed 8 nov 06
Hi Lili,
I have posted some comments on Kathryn's which you may have seen by now -
you are exactly right about the low expansion. The suspender in that
situation would be the Laguna Borate - a sub for GB (not a very good one by
the way) - which will help suspend it - my fix included some clay - I
suspect that will be enough. Granular ilmanite (like granular Manganese)
will sink fast in just about any glaze - the trick is - stir like hell and
glaze while the slop is still moving.
Perhaps - if the bisque is fired on the high side, there is plenty of clay
and the glaze is thick - and the granular ilmanite fine - then it will stay
up better.
I have calculated the fat white - I don't think it is a glaze of mine by
the way - certainly not for cone 6 - simply not enough boron to melt - I
would say it is a cone 8 or cone 10 glaze.
By the way you mean Custer at 35.4 don't you? Even then the recipe adds to
100.4.
The alumina is only 0.39 - clearly not out of bounds for 6, 8 or 10.
You are right the Kathryn's glaze is way over the amount of alumina for a
cone 6 glaze but the limits suggested by Green and by Cooper say there can
be as much as 0.65 alumina - there simply has to be enough boron to melt
it.
If you compare Laguna borate with Gers Borate you will find it has more
boron - which accounts for the extra boron needed to melt all that alumina.
I am assuming that glaze is melting by the way but running with all that
alumina is hard to believe - it is possible we are dealing with a weighing
error?
Have I somehow gotten the wrong impression here? I'm sure that fat white
will not melt at cone 6. The expansion for that glaze is certainly what I
would start with for most clay bodies - and is close to what I revised for
Kathryn.
RR
>About your glaze. There is nothing plastic in it to keep it in suspension.
>Think
>Dead Sea. You have seen pictures of people floating effortlessly in it.
>Reason:
>all that salt keeps them afloat. That--in a loose analogy--is what plastic
>materials,
>clay, bentonite, commercial additives do in the glaze slop.
>So for one I'd add 2-3 % bentonite.
>
>And I have used granular Ilmenite in glazes. If the glaze is suspended
>properly,the
>Ilmenite stays afloat. Do not recall if the specks it creates stay "pebbly"
>in the surface, or melt into teensy blotches.
>
>
>Then I ran your glaze through GlazeMaster(TM) and fell off my chair. (No
>serious
>injury, thank you.)
>
>You say it is runny at c.5-6...but to my amazement your alumina is even over
>the
> c.10-12 limits Rhodes gives, your Silica just a tidge below his highest
>figure of 5.
>
>LiO2 .229
>Na2O .198
>K2O .075
>CaO .498
>Al2O3 .596
>B2O3 .436
>SiO2 4.824
>
>And COE 60.91-- most likely to shiver.
>
>And here is my question for Ron. As I was lying on the floor I looked at
>your
>Fat White recipe. (No, I got that off a Ron message on ClayArt, do not know
>if it is/is not in book)
>
>
>If I copied it correctly:
>
>EPK 13.5
>Frit 3124 5
>Custer spar 354
>Dolomite 19.5
>Talc 1
>Flint 26
>
>And
>
>Na2O .073
>K2O .125
>MgO .351
>CaO .451
>Al2O3 .370
>B2O3 .032
>SiO2 3.146
>
>COE 66.26
>
>Aha! Here is a glaze we know works and ALSO is solidly beyond the "limits"
>for c.6.
>
>What am I missing? I have used glazes beyond the "limits" but my glazes
>tend
>to have a goodly amount of B2O3 which
>I have assumed has a mitigating effect. The Fat White has very little.
>
>And by the way. Like many people who have dealt with proofs etc. I can read
>upside down with ease. So of course I read my medical charts whenever the
>MD is out of the room. On one chart I read: the patient is a
>"well-nourished Caucasian
>woman..." Now you see how much more honest potters are: Fat White would
>have been just as accurate, and less pretentious!
>
>
>
>Lili Krakowski
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
sacredclay on fri 10 nov 06
I like to add a little bit more info to this glaze recipes that I'm
exploring. I've already begged another person not to get mad at me
about it, but I see that there seems to be some puzzlement as to why
the hell am I using this glaze to test. First, I love to explore
glazes, even if I don't understand them (yet). I've made several 100
grams batches with different colorants and yogurt cups, listed the
corresponding numbers taped to the cups to my notebook, have used
laguna borate because gerstley borate suddenly became black gold and
rare. SIX YEARS AGO. Yes, they've been sitting in yogurt cups with
lids in a box in various spots around the studio. I am finally
testing them.No moisture got into these test dry batches. This was a
recipe left to me by a departing artist in resident at a local
community center before I took over. It's horrible on white clay, as
it slips right off the pieces, indicating the clay was maturing
sooner than the glaze.but I absolutely love the glossy transparent
forest green when one add 3% CuCo3.Beautiful with iron wash
underneath it. It remeinds me of when one looks into a dappled
sunshine forest.I'm not a green person, but this is my favorite glaze
when wanting to bring out details better, as it fills in niches more
darkly.so, apparently, my impressions from what I'm gathering from
all is that it's too high in alumina, hence making it unstable, or
unsuitable. but I've never had a problem with the glaze. I used the
pieces that it's on. So perhaps, switching it to gillepsie borate
would be better, from what I've heard, it's the best subsitute for
gerstley borate. which leaads me to another question-what is the
difference between granular manganese and granular illeminite? Are
they both metals in base forms? Idiotic question, I know, so please
don't flame me. It's a waste of typing. but when I have clayarters
here explain it to me in a conversational form, some seed of
understanding forms and an indescribable form of primal bloodlust for
knowledge is born. "Aha! I will find you, oh mysterious glaze! I have
no idea what the hell you are supposed to look like or be, but I know
I will recognize it when I see it." OMG-I think I need to cut back on
the caffeine in the tea. Or not. with warmest regards to all, Kathryn
in NC where it was nice and warm today with all those still glowing
leaves. >
| |
|
