lost wax method of Bronze Casting -- for the curious
Art Bronzes are produced
by means of the lost wax method, a process that has been around
for centuries although now much refined by modern technology.
First, from a mold made from the original a wax casting is made
and prepared. This wax is then dipped in a plaster like material
and allowed to dry. This process is repeated several times until
a shell is built up around the wax. This shell is dried slowly
and carefully over several days so as to avoid cracking, after
which it is placed in an autoclave where heat and steam melt
out the wax. The shell is next put into an oven, which burns
out any remnant of wax and preheats it. Molten bronze is then
poured into the hollow shell at almost 2000 degrees centigrade.
When the bronze is
fully cooled the shell is chipped off very carefully to avoid
damaging the bronze. The casting that emerges is quite rough.
Projecting from it
are thick filler pipes or sprues through which the bronze entered
the casting. These are removed by saw, and the whole surface
of the bronze is finished with abrasives or “chased” to the
Sometimes the piece
is worked up to a bright polish, at other times it is patined
by treating it with chemicals and usually a blow torch which
produces a variety of beautiful finishes. To complete the whole
process usually takes from ten to fifteen days.
is the large amount of labor involved in the production that
accounts for the high price of bronzes. So why bronze when a
similar piece can be made for a fraction of the cost in Pellucida™?
Mostly bronze is more beautiful but sometimes, quite honestly,
I feel that the lightness and translucency of Pellucida™ is
more appropriate for some pieces. But of course what makes bronze
so desirable is its durability. Whether as heirlooms or antiques
they always are valued. They get handed down, auctioned,
bought and sold, donated -- one way or another they go on forever.
John Perry • About
Bronzes • About
Pellucida™ • About