Glaze Calculation
Line Blend Project 2
Problem: Formulate a basic glaze using clay and flux
Objective: To begin to learn the basic technique of known as the “line blend”, to become familiar with the types of clay and flux available for formulating a basic glaze, and to understand the roles of clay and flux in a glaze formula.
Materials: Clays and Fluxes.
Strategy:
Select an industrially available clay and a low temperature flux for the test.
Measure all materials for the line blend by volume and apply to 11 test tiles
After firing, identify the “acceptable” range for a stable glaze at cone 10.
Re-test the “area of focus” (3 tile range) by using exact measurement on a triple beam scale and elaborate with more specific measurements.
Instructions:
Use a “level" table spoon for measuring the material for the first test.
Mix enough water with the dry material to dip test tiles for surface application that is approximately the thickness of a dime.
Fire the first test and identify a range of 3 tiles within the test that is best suited for utilitarian ware.
Elaborate on the “focus area” with a second test that shows 6 tiles (A-F) using the following example:
Focus Area= tiles #6,7,8 of first test (refer to line blend diagram)
Second Test= tile #6 A - 50 grams material A
- 50 grams material B______tile #1
B - 45 grams material A
- 55 grams material B______tile #2
#7 C - 40 grams material A
- 60 grams material A______tile #3
D - 35 grams material A
- 65 grams material B______tile #4
#8 E - 30 grams material A
- 70 grams material B______tile #6
IMPORTANT:
- Use test tiles composed of the same clay body
-The first test is measured by volume, the second test is measured by weight
_______________________________________________________________________________
A comparison of redart and whiting combined in a line blend fired at cone 6 oxidation and cone 10 reduction by Rex Halterman
Tile #
|
Clay %
|
Whiting %
|
11
|
100
|
0
|
12
|
90
|
10
|
13
|
80
|
20
|
14
|
70
|
30
|
15
|
60
|
40
|
16
|
50
|
50
|
17
|
40
|
60
|
18
|
30
|
70
|
19
|
20
|
80
|
20
|
10
|
90
|
21
|
0
|
100
|
| Tile # | Clay % | Whiting % |
| 11 | 100 | 0 |
| 12 | 90 | 10 |
| 13 | 80 | 20 |
| 14 | 70 | 30 |
| 15 | 60 | 40 |
| 16 | 50 | 50 |
| 17 | 40 | 60 |
| 18 | 30 | 70 |
| 19 | 20 | 80 |
| 20 | 10 | 90 |
| 21 | 0 | 100 |
