I suppose that my interest in the use of glass powders isn't just about color. When I decided to fire my glass to a maximum temperature of 1210 degrees Fahrenheit I discovered I could mix glass powder to any tone, tint or hue without the problem of certain color combinations turning brown. Typically, many warm and cold glass colors when mixed together do not yield a color in between, but instead you get brown. That's because under heat the chemical make up (metal oxides) in glass react with each other. Since the glass granules (fine powder) do not get a chance to chemically interact as 1210, you can actually mix glass powder like you would paint.
Just as important to me I recently realized, is that this temperature also gives a very fine sand-like texture to the glass surface. I like this, because if glass melts together into a completely glossy surface you lose a lot of detail, detail that is necessary if you want the finished work to gain interest as you approach it. Also since most glass artist work very hot and want the gloss look, my textured surface serves as a counterpoint to that general tendency. I like that it is soft looking and inviting. You want to touch it not because it is glass, but because its texture is inviting, something new for the senses. It is really just an expensive sand painting to put it crudely, but because of the intensity of the color and the irregularity of texture, and the design of course, it can be a much more as seen in the April 2009 blog post.
The image above was accomplished with glass chalks and regular glass frit. The glass chalks come in stick form just like normal chalks. The intensity of the warm colors is due to the fact that the chalks are more in the enamel family that glass powder. One of the main characteristics of enamels is that they are heavily pigmented. Just a dusting of an enamel coating is required for opacity and richness versus around 1/8 inch or more of glass powder to create the same opacity and richness. Because of this the chalks enable a leap into visual color mixing that is impossible with glass powders. From a distance the small specs of enamel visually mix and as you approach you begin to see individual specs. It is the small size of the spec coupled with its intensity that enables the visual color mixing even when very close to the piece. You have to be closer than a couple of feet before you begin to see the richness in detail, detail that invites you in even closer.
The image above is of a 5x5 inch square, and is probably slightly enlarged on your screen.
To create this texture cover your glass with #1 frit. Bake it to around 1210 and hold for 10-30 minutes depending on your kiln. Do not allow the frit to round over, otherwise you will lose the 'tooth' necessary for the chalk in the next step. You now has a 'canvas' to work on. The sharp edges of the frit act as a texture like pastel paper has, cutting into the chalk and holding the chalk to the surface of the glass. Do your design on the textured surface. When your drawing is complete, bake to 1450 until most of the chalk has melted into the glass surface.
Regretfully, the chalk does not act like glass and you cannot achieve a sandy surface. Most of the finished work will be glossy though somewhat textured, albeit mostly rounded over texture and not very sandy. Since you have to fire so high the regular glass frit which was your 'tooth' will also be melted into a mostly glossy surface. That's OK though since the micro fine pieces of chalk still do show up as fine distinct pieces of color and do not melt into a amorphous blend.
I'm sure to use this technique on a future powder painting.
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