Maria Elaine Lanza on fri 10 sep 99
A comment made on this glaze recipe say it is a "pale blue turquoise with a
frost"... what would it take to deepen the color... increase the Copper
Carbonate amount to possibly 4? if so... would also like to know if it could
be considered foodsafe.
Most turquoise ^4-6 ox recipes I have come across have the nasty Barium
ingredient or Lithium as one of the ingredients... why is that?
This one looks the most promising, but I prefer a richer color... any
suggestions, comments?
Val's Turquoise
Cone 5-9 ox
Custer Feldspar 27.60
Gerstley Borate 16.87
Flint 21.32
Whiting 08.82
Dolomite 02.90
Copper Carbonate 02.34
Bentonite 00.80
Marie Elaine
Lori Wilkinson on wed 5 jul 00
Has anyone actually had this glaze tested at Alfred? Roy, do you wish to
comment. Checked the archives but found no such report. TIA
> >Val's Turquoise
> >Cone 5-9 ox
> >
> >Custer Feldspar 27.60
> >Gerstley Borate 16.87
> >Flint 21.32
> >Whiting 08.82
> >Dolomite 02.90
> >Copper Carbonate 02.34
> >Bentonite 00.80
Lori
Tim & Lori Wilkinson
DOWN TO EARTH POTTERY
Roswell, New Mexico
LorWilk@dfn.com
http://www.geocities.com/SoHo/Gallery/1165/
Craig Martell on thu 6 jul 00
Lori axed:
>Has anyone actually had this glaze tested at Alfred? Roy, do you wish to
>comment. Checked the archives but found no such report.
Hi:
I retotalled this glaze to 100% and ran it thru my glaze program. For a
cone 5-7 glaze it is within or close to the limits for various
oxides. It's at the lowest recommended limit for alumina and just a tiny
bit over the limit for boron so it may shift and run a bit if applied
heavily. I see that this glaze has a firing range that extends above cone
7 and into the 8-9 range. It's out of the suggested limits for alumina and
silica for that temp. It's about .2 moles short of silica which isn't a
disaster but copper will increase the solubility of the glaze somewhat so
there may be some leaching and you won't be able to tell if it's ok without
having it tested. My guess, and that's all it is, would be that this glaze
is probably ok and if you lowered the copper to about 2% it would help.
later, Craig Martell in Oregon
Pat's Pottery on sun 9 sep 07
Thanks to everyone for your calculations. I am going to try the % =
listed by a few of you:>) and try the added 6 EPK suggested by RR. I =
will post to the list with the outcome. This will probably take a month =
or more.
Pat
----- Original Message -----=20
From: Tig Dupr=E9=20
To: pat@stonewarepottery.net=20
Sent: Sunday, September 09, 2007 12:47 PM
Subject: re: Val's Turquoise
--------------------------<>-------------------------My name is =
Pat and I am new to this list. I have a question about glazes and one =
in particular. I have read that all the glaze recipeshould add up to =
100 without the additions. I have two recipes forVAL'S TURQUOISE and =
they both only add up to 77/78 (see below). Am Isafe in making this =
glaze, and could someone explain to me why someglazes don't add up? =
VAL'S TURQUOISE (^5-9) Custer Feldspar 27.6Gerstley Borate =
16.87Flint 21.32Whiting 8.82Dolomite =
2.9Copper Carbonate 2.34Bentonite .8pale blue turquoise with =
a frost--------------------------<>-------------------------
Pat,Not everyone keeps recipes that add up to a constant 100. The =
reasons for making glaze recipes that do add to 100 is the ease of =
conversion by proportion to larger or smaller batch amounts. To make =
this recipe add to a nice, even 100, you simply total the base glaze =
ingredients, then divide each ingredient by that total to get a =
percentage (part per 100).The way *I* would do it is to separate the =
base glaze ingredients from the colorants and suspenders (the copper and =
bentonite), then make the calculations:Custer Feldspar 27.6Gerstley =
Borate 16.87Flint 21.32Whiting 8.82Dolomite =
2.9----------------------------Total 77.51Divide each =
ingredient by 77.51: 27.6 / 77.51 =3D 35.61, and so on...The =
proportions now are:Custer feldspar 35.61Gerstley borate =
21.76Flint 27.51Whiting 11.38Dolomite =
3.74----------------------------Total 100.00Now, since we =
left out the copper, I'd treat that as a percentage of the whole and =
leave it as is. Same with the bentonite, which is used to help keepthe =
materials in suspension in your bucket:Copper carbonate =
2.34Bentonite 0.80Now, just *my* opinion, but I rarely measure to =
the 1/100th of a gram of anything.I prefer to round off numbers to the =
nearest 1/10 gram, 1/10 pound, 1/10 ton, whatever.In this case, I'd make =
the recipe look like:Custer feldspar 35.60Gerstley borate =
21.80Flint 27.50Whiting 11.40Dolomite =
3.70-----------------------------Total 100.00Add:Copper =
carbonate 3.00Bentonite 1.00In this fashion, when you mix a =
1000 gm (1 kilogram) batch, or a 10 kilo batch,everything comes out nice =
and even. I'd make up a 500 gram batch first, and test on a tile or a =
small cup, even an extruded tube.Glazing is a wonderful territory to =
explore. Unlike cooking, you do not necessarily have to stay "in the =
lines." Take one recipe, a reliable clear, and experiment.Add =
opacifiers, add colorants, and see wjhat sort of a palette you can build =
from one glaze.And, above all, ask questions. The Clayart community is =
a priceless resource.Keep in touch,Tig Duprein Port Orchard, Washington, =
USA
Earth and Fire Pottery on sun 9 sep 07
Hi Pat-
this is the val's turquoise I use, and I got it from Alisa too. I use as written, and it is a dependable, forgiving glaze. Also quite popular, a good seller. I fire to cone 6 with it. Other glazes work well over it too. General rule of ceramics and life: what works, works. gregg
My version:
Val's Turquoise
Custer 27.6
Gerst 16.9
Silica 21.3
Dolomite 2.9
Whiting 8.8
Bentonite .8
Copper carb 2.3
Specific Gravity 152.5
Viscosity (#2 Zahn cup) 23
2.5 gallons H20 7500g
same as your version:
Date: Fri, 7 Sep 2007 15:18:44 -0400
From: Pat's Pottery
Subject: VAL'S TURQUOISE %
Hi,=20
My name is Pat and I am new to this list. I have a question about =
glazes and one in particular. I have read that all the glaze recipes =
should add up to 100 without the additions. I have two recipes for =
VAL'S TURQUOISE and they both only add up to 77/78 (see below). Am I =
safe in making this glaze, and could someone explain to me why some =
glazes don't add up?
VAL'S TURQUOISE (^5-9)
Custer Feldspar 27.6
Gerstley Borate 16.87
Flint 21.32
Whiting 8.82
Dolomite 2.9
Copper Carbonate 2.34
Bentonite .8
pale blue turquoise with a frost
Val's Turq. cone 6, oxidation.=20
---------------------------------
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Alisa Clausen on wed 12 sep 07
In CM October 2004
this glaze recipe appeared as
rounded up to 100
36 Custerspar 27.6
22 Gerstley Borate 16.90
27 Silica 21.30
4 Dolomite 2.90
11 Whiting 8.0
ADD
0.8 Bentonite
2.3 Cu Carb.
There is no missing ingredient in the original recipe.
I use this glaze for the inside of some bowls I like to make. I have used
both versions, always subbing gram for gram my local frit for G.B. I like
this glaze. Additionally, I have subbed gram for gram Wollastonite for
Whiting when I was making those tests, and it fired well.
Best regards from Alisa in Denmark
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