Glaze Assignment 1
Glaze Base and Color Blend
Source: Cone 5-6 Glazes (Ceramics Arts Daily book)
Glaze Recipe: Odyssey Base Δ 5-6
Ingredients | Grams/100g. batch | Grams/1000g batch |
Gerstley Borate | 20 | 200 |
Whiting | 10 | 100 |
Nepheline Sulfate | 30 | 300 |
EPK/Kaolin | 10 | 100 |
Silica | 30 | 300 |
Batch Total Weight | 100 | 1000 |
I used two different clay bodies for my test tiles: The white clay is from an unknown bag given to me at the end of last semester, and the red clay is Death Valley. Both are Δ 10 clays.
Instructions:
- Mix up 1000g. of your recipe.
- Divide into 10 cups equally by sight (Approx. 100g./cup)
- Add the following color variations to base (one in each cup) and blend or sieve.
- Dip on numbered Δ 6 tiles – 3 coats:
- One thin coat
- One thicker coat
- Final thicker coat
Test tile numbers/Firing
| Colorant Added to Base | Color when fired | White Δ 6 ox. | Red Δ 6 ox. | White Δ 6 red. | Red Δ 6 red. |
1 | Base Only | *see test tile gallery | 1 | 1 | 13 | 13 |
2 | Zircopax 7% | *see test tile gallery | 2 | 2 | 14 | 14 |
3 | Red Iron Oxide 0.5% | *see test tile gallery | 3 | 3 | 15 | 15 |
4 | Copper Carbonate 3% | *see test tile gallery | 4 | 4 | 16 | 16 |
5 | Chrome Oxide 0.5% | *see test tile gallery | 5 | 5 | 17 | 17 |
6 | Cobalt Carbonate 0.75% | *see test tile gallery | 6 | 6 | 18 | 18 |
7 | Chrome Oxide 0.15% | *see test tile gallery | 7 | 7 | 19 | 19 |
8 | Chrome Oxide 1.0% | *see test tile gallery | 8 | 8 | 20 | 21 |
9 | Chrome Oxide 2.0% | *see test tile gallery | 9 | 9 | 21 | 23 |
10 | Tin Oxide 5% Chrome Ox. 0.15% | *see test tile gallery | 10 | 10 | 22 | 24 |
11 | Tin Oxide 2% Chrome Ox. 0.1% | *see test tile gallery | 11 | 11 | 23 | 25 |
12 | Mason 6600 Black Stain 6% | *see test tile gallery | 12 | 12 | 24 | 27 |
| Required Test |
| Choose from list/Discuss with Instructor |
| Optional/Extra Test |
*Because I used 12 cups instead of 10, I divided 1000÷12 = 83.3333 and figured the percentages from that number to adjust for less base in the cups.
List of Possible Colorants
Yellow Iron 2% | Cobalt Carbonate 1% + Chrome 2% |
Red Iron Oxide 3% + Titanium Dioxide 4% | Nickel Oxide 3% |
Red Iron Oxide 0.5% | Mason 6600 Black Stain 6% |
Iron Oxide 10% + Rutile 4% + Cobalt Carbonate 1% | Any Commercial Stain 3% |
Copper Carbonate 3.5% | Any Commercial Stain 6% |
Copper Carbonate 6% |
|
Copper Carbonate 3.5% + Rutile 5% |
|
Chrome 0.2% + Tin Oxide 7.5% |
|
Glaze Assignment 2
Triaxial Blends
A triaxial blend is an excellent tool for learning about glazes and materials. For this test I am testing crosses between a white base glaze (G13), chrome oxide 2%, and cobalt carbonate 0.5%
Glaze Base: G13
Source: Class glaze
Ingredients | Grams/100g. batch | Grams/1500g batch |
King. | 56.14 | 842.1 |
Dolomite | 9.32 | 139.8 |
EPK/Kaolin | 18.65 | 279.75 |
Talc | 9.32 | 139.8 |
Zircopax | 4.64 | 69.6 |
2% Bentonite | 1.93 | 28.95 |
Batch Total Weight | 100 | 1500 |
I decided to try adding the chrome and cobalt colorants to a base of G-13 glaze, thinking that I would get some nice opaque teal colors form the mix of the two colorants that would also be lightened by the white base. As I was mixing the colorants with the glaze before firing, it looked as if the colors would mix as I expected, but when they were fired, I discovered the blends with the chrome turned a muddy brownish color rather than shades of green.
I was not able to determine exactly why this happened. My research showed that zinc will turn chrome a brownish color, and that magnesium will make chrome muddy, but I was not able to find a reason for why the glaze colors in my test reacted the way they did. I will continue to research this.
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