|What is Stained Glass?
|People have asked us if we “stain” our glass to produce colors. We do not. We purchase each color
which is manufactured by adding impurities (metal oxides) into clear glass.
Silica, soda ash (flux) and limestone (stabilizer) are melted at 2700 degrees producing a clear glass.
This clear base is then colored by adding different metal oxides to it:
Amber = light lead base with carbon
Black = saturated manganese
Blue = cobalt
Green = copper or chromium
Orange = selenium
Purple = manganese or rarely gold
Red = selenium
Rose-pink-cranberry = gold
Yellow = cadmium
Stained glass can be divided into two large categories depending on how it is made:
1. Antique glass refers to the old method that is used to make it and not its age. A glass blower picks
up a glob of glass and blows it into a large cylinder. The pontil is removed and so is the end of the
cylinder. Then the cylinder is carefully split and it is placed in a kiln where it is heated until it is
flattened and then slowly cooled or annealed. This glass varies in thickness and has prismatic effects
which far exceed sheet glass in beauty. Because of its labor intensive nature and the fact that most of
it is made overseas, it is very expensive. Antique flashed glass has a layer of one glass and a thin
layer of another. Both layers can be colored, but most often one is clear and one is colored. It is often
used for etched or sand carved glass where sections of color are are removed and the other color
shows through. It is especially good for clean lettering and intricate designs.
2. Sheet glass may be hand mixed but is machine rolled producing relatively large sheets
Another way of categorizing stained glass is by its degree of opacity:
Cathedral glass – is clear, it can be colored, and depends entirely on transmitted light for its beauty.
Opalescent glass – has a milky base and it can be seen by transmitted light and reflected light.
These glasses can further be characterized by their textures. These are just a few:
Irridized glass is glass that is sprayed on one side with stannous chloride with produces a rainbow
shimmer on the surface similar to an oil sheen on water.
Dichroic glass is produced using a technical vacuum deposition process using quartz crystal and
metal oxides. It's main characteristic is that it has a brilliant transmitted color and a completely
different brilliant reflective color. These two colors shift dramatically depending on the angle of view
&/or whether they are deposited on clear or black glass. Dichroic glass is used more often in cold
fusing glass and warm fusing glass.
Glass can also be painted with vitreous paints that are kilned fired to make them permanent. Painting
allows for a greater degree of detail, perspective, shadowing, and depth.
Other materials that can be used to augment stained glass:
Bevels - straight line &/or clusters
Confetti or fractured streamer glass
Drapery glass – glass with dramatic folds which adds dimension
Glass globs and nuggets
Jewels – cabochons (smooth surface) or faceted
Sand carved glass e.g. flashed glass lettering, veins in leaves & etc.