Part of navigating the use of commercial glazes is understanding the phraseology on the jar. Most glaze manufacturers use terms such as opaque, semi-translucent, translucent, transparent, etc., on their labels. But what do those words really mean? How would each affect the surface if you like to sgraffito, add thick slip, use sprigs, carve, or stamp? To answer this question, I designed a test tile with a few of these techniques to test cone-04 and cone-6 commercial glazes and to illustrate some important factors to consider when using these glazes. 

1 Blank, multi-surface test tile.

The test tile includes sgraffito using black underglaze; dots of white slip; an incised diagonal pattern; gemstone-shaped sprigs from plaster molds; a row of stamps; and a water-etching. It’s important to make a test bar of your desired texture techniques to use when trying out new glazes so you don’t expect one thing from reading the label or looking at a small tile and getting a result you aren’t happy with. 

2 Mayco’s CG975 Sky Diamonds, fired to cone 04: The glaze shows off each texture including the black underglaze. 3 Mayco’s FN021 Olive Green, fired to cone 04: The glaze creates a thick layer of color. It flows into the incised lines and stamps, and there are only breaks in the glaze where the texture is deep. The black underglaze is obscured.

Excerpted from Off the Shelf | Outside the Box by Deanna Ranlett. This book is available in the Ceramic Arts Network Shop.

Topics: Glaze Chemistry

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