Q: How do you design a new glaze?
A: It may sound like magic but to design a new glaze successfully requires no mysterious chants, just a thorough understanding the factors involved in the process. There are two main ways to develop a new glaze:
- Choose suitable raw materials (mostly those that have worked before) and mix them in various proportions to meet a planned series of glaze tests; or
- Choose an appropriate “formula”, based on previous experiments, and derive a “mix-batch” recipe for testing, etc.
In either case, one needs to know detailed particulars about the raw materials on hand. Other factors being equal, step 1 may take many tests before an acceptable result is obtained. Just how many tests is uncertain; personal choice becomes a deciding issue. So mix/try testing may continue for many firings (10?, more?) to achieve a new glaze recipe.
Some glaze designers use step 2. They choose a Seger or Unity formula; this is a shorthand statement of the glaze make-up, or a list of “basic oxides” (essential components) on a “molecular level”. The Seger formula “looks” at a glaze’s batch recipe from the “inside”, and reports the mix of such basic oxides that hopefully will turn into highly viscous (non-runny) molten glass on the surface of the pot. These basic oxides, seldom isolated as such, are contained within the batch recipe’s raw materials.