The Lost Wax Bronze Process
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 completion. The artist's original conception of art 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, whether it is one of a kind or a
recast of a noted collectible artist.
© 1995, EMI
Reprinted with permission from EMI.
- Original Sculpture
- The first step begins with the artist creating an original sculpture.. This
is usually created from wax or clay, though other materials can be used 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 mold, 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 wax pattern to original perfection. Each wax casting is
treated as if it were an original work of art.
- 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 spree cup
is placed onto the wax to receive the molten bronze.
- 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.
- 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,
- 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? Fahrenheit.
(Bronze is an alloy of 95% copper, .02% lead, .02% tin, .06% zinc. 4% silicon.)
- 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 to the bronze.
- An artisan cuts away the sprees 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 sculpture.
- The chased bronze is now treated with 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 a permanent part of the sculpture.
|For Additonal Information
about the Lost Wax Process see: "Lost Wax Bronze Casting" a
photo essay by Harry Jackson, Published by Van Nostrand-Reinhold, New York City,
copywrite 1978 |
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