|Monthly Tech-Tip |
In ceramics, glazes are made by weighing out dry ceramic powdered materials to fill a recipe. Batch recipes often are a combination of a base recipe and additions.
The term 'batch' refers to the actual mixture of materials that you weigh out when you prepare a glaze or clay body batch for production or testing. The term 'recipe' is more correct than 'formula', the latter refers to the chemistry of the mix. Glaze software is used to calculate the chemistry of a batch or to derive a recipe of materials that will produce a specific chemistry (oxide formula).
Recipes are often divided into a base and additions. The base contains the materials that will fire to produce the glass. The additions add color, opacity and variegation to the base. Base recipes are evaluated for their hardness, resistance to crazing and leaching, surface texture, etc. The additions are usually for visual purposes.
When recipes are retotalled it can be done based on the base or or the full recipe.
A screen-shot from Insight-live.
The simple answer is that you should not. The chemistry of stains is proprietary. Stain particles do not dissolve into the glaze melt like other materials, they suspend in the transparent glass to color it. That is why stains are color stable and dependable. In addition, their percentage in the recipe, not the formula, is the predictor of their effect on the fired glaze. Of course they do impose effects on the thermal expansion, melt fluidity, etc., but these must be rationalized by experience and testing. But you can still enter stains into Insight recipes. Consider adding the stains you use to your private materials database (for costing purposes for example).
Desktop Insight 5A - Glaze Formula to Batch Calculations
Learn to use a non-unity calculation to convert a formula into a batch recipe using theoretical and real-world materials. Retotal, round-off and make a side-by-side report.
A term used by potters and in the ceramic industry. It refers to the earthenware, stoneware or porcelain that forms the piece (as opposed to the engobe and covering glaze).