contemporary techniques in architectural glass - International ...

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depends on many factors including the type of paint, colour, surface finish required and
thickness of the glass. Commercial laminated glass cannot be fired. If safety glass is required the
painted glass can be liquid laminated or toughened.
The painted glass can generally be fired and then toughened or can be fired and toughened
in one process. The toughening process rapidly heats and cools the glass, this greatly
strengthens the glass and if it does break it will shatter into tiny harmless fragments. Most
enamel paints can be fired this way but care must be taken not to get paint on the rollers in
the toughening plant. The plant operator needs to be experienced and be prepared to adjust
the firing cycle to suit the glass - paint combination.
Acid Etching and Sandblasting
Goddard & Gibbs and Derix studios used hydrofluoric acid extensively for etching and
polishing the surface of glass. Other acids and combinations can be used but hydrofluoric
is the most common.
The acid eats away the surface of the glass and the resulting finish is dependant on the
strength and temperature of the acid and the immersion time. Inert resists such as bitumen
can be applied by brush or screen or the acid can be mixed into a paste and brushed onto
the glass. These techniques allow for control of the acids effect on the glass. Flashed antique
glass is a 2 or 3 layer glass, with a base colour overlaid with thin layers of different colour. The
acid can be used to remove the top layers allowing the base colours to show.
This process can give results ranging from dramatic to very subtle and is used by many artists.
Acid can also be used to etch clear glass. Hydrofloric acid is highly toxic and can cause severe
burns and the fumes are damaging to the respiratory system.
Derix has a very well set up aciding room with tanks that remove the fumes from the surface
of the liquid. The operators are highly skilled and produce outstanding results. The use of
acid in studios is becoming harder due to the safety and environmental regulations and tight
control on availability. Jose Castrillo said that it would not be long before he would only be
able to use commercially produced acid etched glass.