To familiarize the bronze art
collector with the “lost wax bronze” process, listed below is a step-by-step
description of the procedure. It should be realized that this total casting
process takes several weeks from start to finish. The artist’s original
conception of the piece may take him anywhere from a few weeks to several years
to complete. Thus, realizing the time needed to create a single piece of bronze,
the collector gains a greater appreciation for the value of his bronze
The first step begins with the
artist creating an original sculpture. This is usually created from clay or wax,
though other materials can be used as well.
A flexible silicon mold is made
from the artist’s original. This mold captures every detail put into the
artist’s original work, and is one of the most critical phases in the bronze
process. This mold is used to create duplicates of the original design.
Wax Casting Process
The molds are then used to form
wax figures; molten wax is poured into the rubber mold, producing a perfect Positive
copy of the original sculpture.
The wax casting is removed from
the mold, and a trained artisan hand- finishes the wax pattern to original
perfection. Each wax casting is treated as if it were an original work of art.
Wax rods (gates) are attached to
the wax pattern to allow the even flow of molten metal and to alleviate the
trapping of air and gas. A sprue cup is placed onto the wax to receive
the molten bronze.
The wax is then coated with an
“investment,” a liquid re-factory ceramic. Several layers are applied
creating a stable mold that is allowed to cure for several days.
The piece, now coated in ceramic
shell, is fired in a kiln. This bakes the shell and eliminates the wax, leaving
a cavity in its place. (Thus, the term, “LOST WAX”)
The ceramic shell is removed from
the kiln and molten bronze is immediately poured at a temperature of 2100°
Fahrenheit. (Bronze is an alloy of 95% copper, .02% lead, .02% tin, .06% zinc,
and 4% silicon.)
After cooling for several hours,
the ceramic shell is carefully broken away, revealing the bronze sculpture
Fine sand particles are blasted
under air pressure to remove the last traces of ceramic shell that adheres to
An artisan cuts away the sprues
and gates. After this, the pieces of the sculpture are welded together by
By grinding, chasing, sanding and
polishing, all areas are blended back to make the bronze look exactly like the
artist’s original sculpture.
The finish bronze sculpture is now
treated with different chemicals and heat to give it the chosen color according
to the artist’s specifications. The patina is sealed under a wax coating and
becomes part of the sculpture.