Material Line Blends
Aim:
1. To use the line blend method to vary 2 glaze materials in a base glaze.
2. Understand the maths for ascertaining the proportions in various mixes.
3. To discover the limits of materials in a glaze using the glazes on the attached sheet.
Method:
1. Make up both glazes using the same amount of water so that their volumes are identical. Start with the glaze that has the most clay in it and once that glaze is mixed to the usual cream consistency then make the other glaze equal in volume.
2. The glazes need constant stirring throughout testing as they can settle very quickly.
3. Using either a syringe or a measuring spoon remove some of glaze A as per the schedule below and empty it to an empty cup. Add the balance of glaze B as per the schedule and mix the two together. Sieving is not necessary.
| TEST NUMBER |
1 |
2 |
3 |
4 |
5 |
6 |
| RATIO A:B |
100:0 |
80:20 |
60:40 |
40:60 |
20:80 |
100:0 |
| AMOUNT OF A |
|
80ml |
60ml |
40ml |
20ml |
|
| AMOUNT OF B |
|
20ml |
40ml |
60ml |
80ml |
|
4. Dip the test tile into this mixture and label according to the schedule. Then move onto the next test. For tests No 1 and 6 just dip the test tile into the large batch of glaze A and B respectively.
5. Label all the tests with MLB, then the glaze combinations (eg. A.B), then the number of the test.
Analysis:
Use the 'Test Glaze Sheet' to summarise each test series. In particular note the following:
1. The way the texture of the surface changes across the series, note which end feels rough, which end feels smooth.
2. Note the way crazing can vary across the series.
Summary:
This version of the line blend is a very useful tool for varying one or two ingredients in a glaze to discover the function of those ingredients, or to fine tune a glaze. The number of steps may be as large as you like, but practically speaking 5 steps would be the minimum and around 15 would be as fine as ever needed. The maths needed to derive a glaze in the series appears daunting at first but with practice is very logical. |
