Paul Gruner on fri 11 apr 08
While doing some glaze tests I ran across a glaze that gets a very rich
pastel blue from Nickel. With some cobalt added there was some interesting
variation in shades of blue (though it was just a small tile - hard to say
what it would do on a bigger piece.) It was also very matte.
The glaze uses mostly Zinc and Strontium as fluxes and it has very low
levels of Silica and Alumina. I'm going to try to reformulate it to bring
those up to 'limit' levels. But here are my questions:
Are Zinc and Strontium good enough fluxes for a cone 6 glaze?
How is leaching in a Zinc/Strontium glaze? Could this ever be considered
food-safe?
Do I need to add a little fritted boron to help it melt?
What other colorans might be interesting to try in a zinc/strontium base?
Suggestions? I understand that some colors look muddy with zinc.
Here's the original glaze and the one I'm thinking of trying. I might do a
line test between the two. What do you think?
Thanks,
Paul Gruner
------------------------
Original Zinc/Strontium/Nickel Blue:
5.00 Silica
5.00 EP Kaolin
35.00 G-200 Feldspar
30.00 Strontium Carbonate
15.00 Zinc Oxide
1.00 *Nickel Oxide
---
91.0 Total
0.01* CaO
0.00* MgO
0.09* K2O
0.04* Na2O
0.41* ZnO
0.45* SrO
0.00* P2O5
0.00 TiO2
0.18 Al2O3
1.13 SiO2
0.00 Fe2O3
Si:Al: 6.20
SiB:Al: 6.20
Thermal Expansion: 765.67
----------------------------
Pauls test Zinc Strontium Nickel
19.00 Silica
19.00 EP Kaolin
26.00 G-200 Feldspar
19.00 Strontium Carbonate
9.00 Zinc Oxide
8.00 Frit 3195
1.00 *Nickel Oxide
---
101.0 Total
0.07* CaO
0.00* MgO
0.10* K2O
0.07* Na2O
0.35* ZnO
0.41* SrO
0.00* P2O5
0.00 TiO2
0.41 Al2O3
0.08 B2O3
2.60 SiO2
0.00 Fe2O3
Si:Al: 6.41
SiB:Al: 6.62
Thermal Expansion: 503.35
John Post on sat 12 apr 08
Hi Paul,
You can see a Currie grid that I made using black nickel as a
colorant. The colors you can get from nickel are very sensitive to
alumina as you will see in the grid. When there is a small amount of
alumina, nickel can yield a violet. When there is a bit more, it goes
blue. You can see the grid on the cone 6 glaze website below.
John Post
Sterling Heights, Michigan
http://www.johnpost.us :: cone 6 glaze website ::
http://www.wemakeart.org :: elementary art website ::
On Apr 11, 2008, at 11:58 AM, Paul Gruner wrote:
> While doing some glaze tests I ran across a glaze that gets a very
> rich
> pastel blue from Nickel. With some cobalt added there was some
> interesting
> variation in shades of blue (though it was just a small tile - hard
> to say
> what it would do on a bigger piece.) It was also very matte.
>
> The glaze uses mostly Zinc and Strontium as fluxes and it has very low
> levels of Silica and Alumina. I'm going to try to reformulate it to
> bring
> those up to 'limit' levels.
Ron Roy on thu 17 apr 08
Hi Paul,
The zinc will help melt at cone 6 - the strontium will help but it will not
work by itself.
The glaze is matte because the strontium is over supplied - your version
will not be the same because there is a more reasonable amount of
strontium. Fire it anyway - you may get some interesting colours.
The first glaze is short of both silica and alumina - it will not be stable.
Zinc usually makes iron go muddy - works well with blues.
Otherwise you are on the right track and you got the expansion down as well.
Let me know how yours fires - perhaps I can make some suggestions.
This is a good time to get into line blends - there are many kinds and you
can tailor them to give the info you want.
RR
>While doing some glaze tests I ran across a glaze that gets a very rich
>pastel blue from Nickel. With some cobalt added there was some interesting
>variation in shades of blue (though it was just a small tile - hard to say
>what it would do on a bigger piece.) It was also very matte.
>
>The glaze uses mostly Zinc and Strontium as fluxes and it has very low
>levels of Silica and Alumina. I'm going to try to reformulate it to bring
>those up to 'limit' levels. But here are my questions:
>Are Zinc and Strontium good enough fluxes for a cone 6 glaze?
>How is leaching in a Zinc/Strontium glaze? Could this ever be considered
>food-safe?
>Do I need to add a little fritted boron to help it melt?
>What other colorans might be interesting to try in a zinc/strontium base?
>Suggestions? I understand that some colors look muddy with zinc.
>
>Here's the original glaze and the one I'm thinking of trying. I might do a
>line test between the two. What do you think?
>
>Thanks,
>Paul Gruner
>
>------------------------
>Original Zinc/Strontium/Nickel Blue:
>
>5.00 Silica
>5.00 EP Kaolin
>35.00 G-200 Feldspar
>30.00 Strontium Carbonate
>15.00 Zinc Oxide
>1.00 *Nickel Oxide
>---
>91.0 Total
>
>0.01* CaO
>0.00* MgO
>0.09* K2O
>0.04* Na2O
>0.41* ZnO
>0.45* SrO
>0.00* P2O5
>0.00 TiO2
>0.18 Al2O3
>1.13 SiO2
>0.00 Fe2O3
>
>Si:Al: 6.20
>SiB:Al: 6.20
>Thermal Expansion: 765.67
>
>----------------------------
>Pauls test Zinc Strontium Nickel
>
>19.00 Silica
>19.00 EP Kaolin
>26.00 G-200 Feldspar
>19.00 Strontium Carbonate
>9.00 Zinc Oxide
>8.00 Frit 3195
>1.00 *Nickel Oxide
>---
>101.0 Total
>
>
>0.07* CaO
>0.00* MgO
>0.10* K2O
>0.07* Na2O
>0.35* ZnO
>0.41* SrO
>0.00* P2O5
>0.00 TiO2
>0.41 Al2O3
>0.08 B2O3
>2.60 SiO2
>0.00 Fe2O3
>
>Si:Al: 6.41
>SiB:Al: 6.62
>Thermal Expansion: 503.35
Ron Roy
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Paul Gruner on sat 19 apr 08
Ron,
Thanks for the info and advice. I will do a line blend and post the
results. Maybe I'll try the base glaze with other colorants - besides
Nickel I think I'll try Copper and a blend of Nickel with a small amount
of cobalt.
John Post,
Thanks for link to your site. I've seen it before and it's given me a lot
of inspiration and useful information.
-Paul Gruner
| |
|
