Q: I know there is a process to make plaster objects look like bronze. How
is it done?
A: The first thing is to prime the plaster item with shellac, first using
a light coat cut with an equal part of denatured alcohol, letting that dry,
then applying a full-strength coat. This seals the plaster and prevents
it from sucking the volatile components out of the subsequent layers of
paint, interfering with their film formation. After the shellac is dry,
put on an oil or lacquer based gold paint, either by brushing or spraying.
There are various types of gold paint available, which vary widely in their
effects. Then cover the whole thing with a dark brown colored oil paint,
and wipe it off the high spots while it is still wet. This process can be
repeated several times, until the "antiquing" seems about right.
Optionally, one can go for a "verdigris" effect, using shades
of green oil paint over the brown once the brown has dried, rubbing it off
the high spots just a little. Paste wax can be used over the surface for
protection and glossiness.
There are other versions of this process which depend on coatings containing
copper or bronze powder. These can be treated with chemicals to obtain an
actual patina, either greens or shades of brown. Another approach is to
add atomized copper or brass to certain formulations of gypsum cement, in
sufficient concentration to make the surface somewhat metallic. This can
then be patinated in a similar way. Or, alternatively, one can paint the
plaster item with a conductive solution, then electroplate it with copper.
This can then be treated with chemicals to achieve various color effects.
Andrew Werby - United Artworks
RETURN TO UNITED ARTWORKS HOME PAGE