1. Glazing Review
Basic Glaze Chemistry

2. What is in a glaze?
1. Flux - any ingredient that is used to help melt the glaze or to lower the temperature that the glaze will melt at.
Commonly used fluxes: Limestone, gerstley borate, dolomite, lithium carbonate
2. Stabilizer - any ingredient that is used to extend the melting range of a glaze and to stiffen the glaze.
Commonly used stablizers: Kaolin (china clay), Alumina

3. What’s in a glaze continued..
3. Glass former - the main ingredient of a glaze.
Silica is the main glass former.
4. Colorant - add color to the base glaze and are used in small amounts, they are usually metals like copper.
Common colorants: copper carbonate, cobalt cabonate, iron oxide, rutile

4. Opacity Transparent Translucent Opaque Completely see through, clear
Light can be seen through it, but is not transparent
Opaque
Solid, glaze completely covers color of clay, no light passes through

5. Types of Firings we do: Oxidation Reduction
a firing during which the kiln chamber retains an ample supply of oxygen. An electric kiln always gives an oxidizing fire
Bisque and low fire glazes
Reduction
a firing using insufficient oxygen; carbon monoxide thus formed unites with oxygen from the clay and glaze to form carbon dioxide, which produces color changes in the glazes

6. Pyrometric Cones
Cones are specially designed to bend at specific times during a firing
High Fire
Cone 10 ~2350ºF
Bisque and low fire glaze
cone 06 ~1860ºF

7. Low-Fire Glaze (1860ºF) In small plastic containers
Brush it on from different angles
2-3 coats

8. High-Fire In the buckets Glassy Food-safe Use tongs to dip
Wipe off bottom!!!

9. How to High-Fire glaze Stir up glaze for 30 sec Blow dust off project
Hold with tongs
Dip in glaze for 2 seconds
Don’t touch when wet

10. DO NOT attempt to glaze over fingers!!!!!!!
Projects with fingerprints will be REJECTED and must be washed off and re-glazed
Please use tongs

11. Glaze drips downward When it’s a hot liquid, it drips downward
Wipe up about 1/2 an inch up the side

12. Put it back on the shelf to dry
If you mess up…its OK!
Wash it off in the sink
Put it back on the shelf to dry
Try again tomorrow!

13. Crawling
The separation of a glaze coating from the clay caused by too heavy application, or glazing a dusty or dirty pot
This results in exposed areas of unglazed clay.

14. Dry foot
to clean the bottom of a glazed piece before firing

15. Wax Resist
a method of decorating pottery by brushing on a design with a hot melted wax emulsion
this will prevent an applied stain or glaze from adhering to the decorated portions

16. Wax Resist
Paint on wax resist where you do not want glaze (bottom and ½ inch up side)
Be careful not to drip
Allow to fully dry before dipping
Double check base for glaze droplets

17. Happy Glazing!