Advice on glaze mixing

WORDS TO THE WISE: When copying glaze formulae, beware of unclear abbreviations- use standard abbreviations and write legibly. Be careful when copying easily confused materials- don't write "manganese" when the formula calls for "magnesium". Also, don't abbreviate "copper carbonate" to "copper" or to "co"- when you use the formula, you won't know if you need copper carbonate, red copper oxide, black copper oxide, copper sulphate or a cobalt compound. Cop. Carb. is acceptable as it is hard to confuse.

PREPARE THE GLAZE CAREFULLY: 100 grams is the smallest safe glaze test- as the batch size shrinks, accuracy in measuring and careful mixing become more and more crucial. Dry mix the glaze throughly and add water cautiously and gradually- start with less than 1/4 cup for 100 grams and add more water by the spoonful. Mixing the glaze with too much water results in inaccurate glaze application and a useless test. The glaze should be of a very heavy heavy cream consistency. If you are in doubt, stop while the glaze seems too thick and get some advice!

Mark the bottom of the tile in iron oxide. The iron oxide application should be just thick enough to be opaque.

1. Make sure there is enough of all the glaze ingredients before you start.
2. Write down the recipe. Enter the recipe in glaze log.
3. Mark the container with the recipe name and your name and date.
4. Remember, open only one glaze ingredient at a time.
   1. Make sure the scale is balanced before you start.
   2. You must ask before using materials without a black band on the container. Consistency of the glaze, and thickness of glaze coat are critical.
   3. Common Glaze Test Problems:
   • GLAZE TOO THIN
   • GLAZE TOO THICK
   • ATYPICAL APPLICATION
   • LACK OF DOCUMENTATION
   • Poor marking of the tile.

   Used glaze tests are collected at the end of the year for consolidation into a scrap glaze. Please do not pour significant quantities glazes into the sink.