To familiarize the bronze art collector with the bronze casting process, listed be low is a step-by-step description of the procedure. It should be realized that this total casting process takes several weeks from start to completion. The artist’s original conception of art may take him/her anywhere from a few weeks to several years to complete. Realizing the time needed to create a single piece of bronze the collector gains a greater appreciation for the value of his/her bronze, whether it is a one of a kind or a recast of an original sculpture.
The first step begins with the artist creating an original sculpture. This is usually created in wax or clay, though other materials can be uses as well.
RUBBER MOLD: A flexible 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.
THE WAX CASTING: The molds are then used to form wax figures; molten wax is poured into the rubber molds, producing a perfect copy of the original sculpture.
WAX CHASING: The wax casting is removed from the mold, and a trained artisan hand-finishes the was pattern to original perfection. Each was casting is treaded as if it were an original work of art.
SPRUING: Wax rods, called 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.
INVESTING: The wax is then coated with an “Investment”, a liquid refectory ceramic. Several layers are applied creating a stable mold, which is allowed to cure for several days.
BURN-OUT: The piece, now coated with a ceramic shell, is fired in a kiln, this bakes the shell and eliminates the was, leaving an empty cavity in it’s place. (thus the term, “Lost Wax”).
CASTING: The ceramic shell is removed from the kiln and molten bronze is immediately poured into the form. The bronze is poured at a temperature of 2100 degrees Fahrenheit. (Bronze is an alloy of 95% copper, .02% tin, .06% zinc, 4% silicon).
BREAKOUT: After cooling for several hours, the ceramic shell is carefully broken away, revealing the bronze sculpture within.
SAND BLASTING: Fine sand particles are blasted under air pressure to remove the last traces of ceramic shell that adheres tot he bronze.
FINISHING: An artisan cuts away the sprues and gates. Then by grinding, chasing, sanding and polishing all areas are blended back to make the bronze look exactly like the artist’s original wax sculpture.
PATINA: The chased bronze is now given a color according to the artist’s specification. The age and kinds of chemicals used, how it is applied, the heat and duration of this process creates each color patina finish on the sculpture as a unique work of art and will last for many years to come. The patina is sealed under a wax coating, which is put on while the bronze is very hot, allowing it to seal the piece and become a permanent part of the sculpture.
These steps describing the procedures, and done by a trained artisan by hand with special care, is why each piece of sculpture has a high value. A value that can increase throughout the years. Each piece of sculpture has a limited edition made of each piece. Each piece is signed by the artist and numbered. Each owner knows which piece of sculpture in the addition they have, and the total number of pieces produced in that edition.