nderglaze crayons or pencils in a variety of colors can be used to draw on greenware or bisqued ware. The piece can then be glazed and fired, fixing the clors permanently underneathe the glaze. Underglaze crayons give the freedom to draw anything that the artist wants to or can draw with a crayon or pencil. As commercial underglaze pencils can be quite expensive, here is a recipe on how to make your own.
Ingredients:
| White Firing Ball Clay Potash Feldspar Flint (Quartz) Bentonite Colorant (Iron Oxide, Copper Carbonate, Cobalt Oxide/Cobalt Carbonate, any undeglaze colorant) |
50 25 25 5 15 |
Method 1:
Mix the ingredients with the desired colors and dry sieve the powder through an 80 mesh. Be sure to wear a mask and gloves, if using toxic colorants. Weigh the ingredients and then measure out 45% of that weight in water. Example: for 100 grams of powder, take 45 grams or 45 ml (equivalent measurement) of water. For every 45 mls (per 100 gms of powder) of water, mix in a teaspoon of sodium silicate. Add the water to the powder and mix thoroughly with a fork or similar tool. The paste should now have a thick consisitancy which can be rolled into a pencil shape. Use gloves when rolling the pencils into shape if your mixture contains toxic materials. After drying, fire the pencils/crayons to 800o - 900o C.
Method 2:
Use the dry ingredients as listed above and add wax resist in increments until a hard paste is achieved. Roll pencils as in Method 1, then let dry for a couple of days (depending on the weather conditions in your country), or force dry in an oven or microwave (on low!). The wax crayons are more suitable for drawing on greenware, in which case the wax is burnt off. If painting on bisqued ware, the wax resist component will influence glaze coverage on the painted areas.