lili krakowski on wed 9 dec 09
Dear Amy:
Glazing is like cooking. Dishes include a certain number of specific =3D
ingredients, which are "adjusted" to meet tastes and needs.
When you make meatloaf you use X amount of meat (choose kind), add y =3D
amount of bread or breadcrumbs (or variants such as cracker crumbs or =3D
matzo meal) z number of eggs per pound of meat, and different (to taste) =
=3D
seasonings.
So if your brother-in-law is coming to dinner and he hates onions, you =3D
leave them out. If your best buddy, "The Onion Queen", comes to dinner, =
=3D
you add lots.
Unlike many dishes, with glaze we cannot "taste as we go". You have to =3D
make tests. Actually, as I learned from a friend, it is good to cook =3D
little test "meatballs" of your meat loaf mix so you CAN taste the mix =3D
without risk of salmonella or whatever.
Now your glaze is:
Dolomite 340.188 grams
Whiting 136.572 grams
Custar feldspar 5 pounds 181.421 grams
EPK 2 pounds 226.792grams
Mason black stain 90.716 grams
Manganese Dioxide 90.716 grams
Cobalt carbonate 11.793 grams
Or, as GlazeMaster (TM) tells me:
=3D20
Amount Ingredient
38.5 Dolomite
15.4 Whiting
20.5 Feldspar--Custer
25.6 Kaolin--EPK
Unity Oxide
.018 Na2O
.039 K2O
.332 MgO
.612 CaO
.217 Al2O3
.729 SiO2
. =3D20
84.5 Exp
And you have about 10% each of black stain and of manganese, and about =3D
1% cobalt.
Back to meatloaf (yes, of course, you can use Tofu!)(Gee!)
You build the meatloaf around the meat. That is the largest and most =3D
"determining" ingredient.
In a glaze that ingredient is the silica. The silica in your glaze is =3D
woefully low! It is even low for c.6, which, RonJohn tell us, should be =
=3D
at least 2.50, and your alumina (hang in there) at least .25 FOR CONE 6.
Truth to tell, I have no idea why this glaze ever stayed on the pot =3D
(horses, dogs) to begin with. I thought about this all morning while =3D
snowblowing (first time this year--and us in a SnowBelt) and my best =3D
guess is that the glaze has been SO fluid it soaked right into the clay, =
=3D
and left just a trace on the surface. So that, there really is little =3D
glaze if any, just enough to glue on the colorants. ("Starved glaze".)
To "adjust" this glaze to a proper c.10 you would up the clay and =3D
flint.
16.3 Dolomite
6.5 Whiting
8.7 Feldspar--Custer
27.6 Kaolin--EPK
40.9 Flint
.017 Na2O
.038 K2O
.306 MgO
.64 CaO
1.000 Total
.42 Al2O3
.006 Fe2O3
3.428 SiO2
57 Exp
But I am convinced (PROVE ME WRONG!) that this would give a totally =3D
different result from what you have now.
I hope someone else who knows more about stains/glazes for sculptures =3D
can help. Because this is beyond my knowledge.
A few more points. You have a like 22% colorants in there. I suspect =3D
that that is a whole lot too much.
I would be grateful if you could/would put a glazed and fired horse or =3D
dog fragment into some dishwasher liquid and see what happens. Ditto, =3D
put a fragment into some plain vinegar, and see what happens after a few =
=3D
days..
Yes. One can take a bit of a dried out glaze, weigh it out dry, then add =
=3D
whatever to the mix.
Glaze tests are generally made in 100gram batches, though very often a =3D
potter will make a bigger batch--it depends. If you recalculate any =3D
glaze to % you have your 100 grams. You then would weigh out the whole =3D
entire batch of existing dry glaze, and add the % needed of new =3D
material.
I do not work at c.10.
But here is a recipe of Lucie Rie's for 1250 oxidation, (Orton c.7) =3D
which seems enough in the ballpark to be adaptable.
Recipe Name: lucie rie dolomitic glaze--The Ceramic Review Book of Clay =
=3D
Bodies & Glaze Recipes, Cooper & Lewentein.
Cone: Color: =3D20
Firing: Surface: =3D20
Amount Ingredient
64 Feldspar--Custer
13 Dolomite
13 Whiting
12 Kaolin--EPK
102 Total
Unity Oxide
.084 Na2O
.185 K2O
.183 MgO
.548 CaO
1.000 Total
.409 Al2O3
.004 Fe2O3
2.227 SiO2
84.1 Exp
It could be a starting point. Raise the clay in 5% additions...see what =
=3D
happens.
Sorry I could not help more.
Also: Do read THE BASIC INTERNET GLAZE COURSE on (yes!) the Internet. I =
=3D
wrote it to help people who have problems with glaze calculation. And =3D
no, I never made a penny from it, am not related to it--but several have =
=3D
told me it works.
And lettuce know what happens. With lettuce at over $2 a head, we =3D
cannot afford to waste!
Lili Krakowski
Be of good courage
Amy Romaniec on thu 10 dec 09
Thank you Lili=3D2C
I am excited to try your suggestions.
I did not know enough about glazes to know a starved glaze when I see one. =
=3D
I had always used the glaze in question under a thin white . Maybe it fed =
=3D
the "starved "part.
Two years ago I down loaded The Basic internet Glaze Course. Guess I should=
=3D
have asked for help then.
I am Below "basic" in my understanding.
If I were told to use "one whole egg" I would wonder if it meant the shell=
=3D
too.
I do envy your understanding of the glazes!
If I just went with the black stain and left out the mang and cobalt. I s=
=3D
hould probably increase the stain . Right?
I am worried about reproducing the "test " If it comes out great.
When my cooking fails I have four dogs waiting on tip toe!!!
I have test pieces ready. note pad etc.
Off to Mix
Thanks so much=3D2C
Amy
highhorsefarm.com
I=3D20
> Date: Wed=3D2C 9 Dec 2009 17:27:46 -0500
> From: mlkrakowski@CITLINK.NET
> Subject: Amy's Black Glaze dilemma!
> To: Clayart@LSV.CERAMICS.ORG
>=3D20
> Dear Amy:
>=3D20
> Glazing is like cooking. Dishes include a certain number of specific ing=
=3D
redients=3D2C which are "adjusted" to meet tastes and needs.
>=3D20
> When you make meatloaf you use X amount of meat (choose kind)=3D2C add y =
am=3D
ount of bread or breadcrumbs (or variants such as cracker crumbs or matzo m=
=3D
eal) z number of eggs per pound of meat=3D2C and different (to taste) seaso=
ni=3D
ngs.
>=3D20
> So if your brother-in-law is coming to dinner and he hates onions=3D2C yo=
u =3D
leave them out. If your best buddy=3D2C "The Onion Queen"=3D2C comes to di=
nner=3D
=3D2C you add lots.
>=3D20
> Unlike many dishes=3D2C with glaze we cannot "taste as we go". You have =
to=3D
make tests. Actually=3D2C as I learned from a friend=3D2C it is good to =
cook=3D
little test "meatballs" of your meat loaf mix so you CAN taste the mix wi=
=3D
thout risk of salmonella or whatever.
>=3D20
> Now your glaze is:
>=3D20
> Dolomite 340.188 grams
> Whiting 136.572 grams
> Custar feldspar 5 pounds 181.421 grams
> EPK 2 pounds 226.792grams
> Mason black stain 90.716 grams
> Manganese Dioxide 90.716 grams
> Cobalt carbonate 11.793 grams
>=3D20
> Or=3D2C as GlazeMaster (TM) tells me:
>=3D20
> =3D20
>=3D20
> Amount Ingredient
> 38.5 Dolomite
> 15.4 Whiting
> 20.5 Feldspar--Custer
> 25.6 Kaolin--EPK
>=3D20
>=3D20
>=3D20
> Unity Oxide
> .018 Na2O
> .039 K2O
> .332 MgO
> .612 CaO
>=3D20
>=3D20
> .217 Al2O3
> .729 SiO2
> . =3D20
>=3D20
>=3D20
> 84.5 Exp
>=3D20
>=3D20
> And you have about 10% each of black stain and of manganese=3D2C and abou=
t =3D
1% cobalt.
>=3D20
> Back to meatloaf (yes=3D2C of course=3D2C you can use Tofu!)(Gee!)
>=3D20
> You build the meatloaf around the meat. That is the largest and most "de=
=3D
termining" ingredient.
> In a glaze that ingredient is the silica. The silica in your glaze is wo=
=3D
efully low! It is even low for c.6=3D2C which=3D2C RonJohn tell us=3D2C sh=
ould b=3D
e at least 2.50=3D2C and your alumina (hang in there) at least .25 FOR CONE=
6=3D
.
>=3D20
> Truth to tell=3D2C I have no idea why this glaze ever stayed on the pot (=
ho=3D
rses=3D2C dogs) to begin with. I thought about this all morning while snowb=
lo=3D
wing (first time this year--and us in a SnowBelt) and my best guess is that=
=3D
the glaze has been SO fluid it soaked right into the clay=3D2C and left ju=
st=3D
a trace on the surface. So that=3D2C there really is little glaze if any=
=3D2C =3D
just enough to glue on the colorants. ("Starved glaze".)
>=3D20
> To "adjust" this glaze to a proper c.10 you would up the clay and flint.
>=3D20
>=3D20
> 16.3 Dolomite
> 6.5 Whiting
> 8.7 Feldspar--Custer
> 27.6 Kaolin--EPK
> 40.9 Flint
>=3D20
>=3D20
> .017 Na2O
> .038 K2O
> .306 MgO
> .64 CaO
> 1.000 Total
>=3D20
> .42 Al2O3
> .006 Fe2O3
>=3D20
> 3.428 SiO2
> 57 Exp
>=3D20
>=3D20
> But I am convinced (PROVE ME WRONG!) that this would give a totally diffe=
=3D
rent result from what you have now.
>=3D20
> I hope someone else who knows more about stains/glazes for sculptures can=
=3D
help. Because this is beyond my knowledge.
>=3D20
> A few more points. You have a like 22% colorants in there. I suspect th=
=3D
at that is a whole lot too much.
>=3D20
> I would be grateful if you could/would put a glazed and fired horse or do=
=3D
g fragment into some dishwasher liquid and see what happens. Ditto=3D2C pu=
t =3D
a fragment into some plain vinegar=3D2C and see what happens after a few da=
ys=3D
..
>=3D20
> Yes. One can take a bit of a dried out glaze=3D2C weigh it out dry=3D2C t=
hen =3D
add whatever to the mix.
>=3D20
> Glaze tests are generally made in 100gram batches=3D2C though very often =
a =3D
potter will make a bigger batch--it depends. If you recalculate any glaze =
=3D
to % you have your 100 grams. You then would weigh out the whole entire ba=
=3D
tch of existing dry glaze=3D2C and add the % needed of new material.
>=3D20
> I do not work at c.10.
>=3D20
> But here is a recipe of Lucie Rie's for 1250 oxidation=3D2C (Orton c.7) =
wh=3D
ich seems enough in the ballpark to be adaptable.
>=3D20
> Recipe Name: lucie rie dolomitic glaze--The Ceramic Review Book of Clay =
=3D
Bodies & Glaze Recipes=3D2C Cooper & Lewentein.
>=3D20
> Cone: Color: =3D20
> Firing: Surface: =3D20
>=3D20
> Amount Ingredient
> 64 Feldspar--Custer
> 13 Dolomite
> 13 Whiting
> 12 Kaolin--EPK
>=3D20
> 102 Total
>=3D20
>=3D20
> Unity Oxide
> .084 Na2O
> .185 K2O
> .183 MgO
> .548 CaO
> 1.000 Total
>=3D20
> .409 Al2O3
> .004 Fe2O3
>=3D20
> 2.227 SiO2
>=3D20
> 84.1 Exp
>=3D20
> It could be a starting point. Raise the clay in 5% additions...see what =
=3D
happens.
> Sorry I could not help more.
>=3D20
> Also: Do read THE BASIC INTERNET GLAZE COURSE on (yes!) the Internet. I =
=3D
wrote it to help people who have problems with glaze calculation. And no=
=3D
=3D2C I never made a penny from it=3D2C am not related to it--but several h=
ave =3D
told me it works.
>=3D20
> And lettuce know what happens. With lettuce at over $2 a head=3D2C we ca=
nn=3D
ot afford to waste!
>=3D20
>=3D20
>=3D20
>=3D20
>=3D20
>=3D20
> Lili Krakowski
> Be of good courage
=3D20
_________________________________________________________________
Windows Live Hotmail gives you a free=3D2Cexclusive gift.
http://www.microsoft.com/windows/windowslive/hotmail_bl1/hotmail_bl1.aspx?o=
=3D
cid=3D3DPID23879::T:WLMTAGL:ON:WL:en-ww:WM_IMHM_7:092009=3D
| |
|
