The first step in creating a bronze sculpture using the lost wax casting method is to sculpt the original piece from which the mold will be made. All the detail is captured in this stage, which is the basis for the rest of the process.
The next step of casting is to pour molten wax into the mold, using layers of wax to form an exact duplicate of the original casting.
The wax is pulled from the mold and detailed, or chased, welded and polished by individual artisans. Each piece may contain some small variation from the original, but the reproductions remain true to the original sculpture.
Wax rods and pouring cups are attached to the wax casting to assure a full pour. Using a temperature controlled climate, the wax casting is dipped into investment liquid (liquid clay, essentially). After the first dip, a powder is applied to the clay, and on subsequent dips a layer of ceramic sand is applied, creating a ceramic mold that must be allowed to dry between layers.
The ceramic shell is then placed into a kiln and fired, the shell is baked and the wax is melted (lost) from the shell, creating a hollow ceramic shell mold and the phrase ‘lost wax casting.’ The mold is removed from the kiln, and molten bronze is poured into the shell at about 2100 degrees Fahrenheit.
After several hours of cooling, the unfinished bronze is carefully stripped of the ceramic shell. The ceramic shell fragments are carefully removed fromthe bronze, which is carefully inspected at this stage.
If required, this is the time when a master craftsman would weld larger sections together, and chase or re-detail the weld marks. Afterward, the craftsman uses a process called ‘glass beading’ in which the bronze is sprayed with powdered glass under extremely high pressures to ensure an even bronze finish.
The bronze is now hand polished and heated to await the patina application. The patina is hand applied by the artisan, and a layer of wax is hand applied with heat to ensure a lustrous patina finish. After a final inspection, the bronze sculpture is now ready for delivery and display.
The Lost Wax Casting Method History
The history of bronze sculpture dates back several thousand years, and was predominately used in Greece, Egypt, Rome and the Near Eastern civilizations. Many of the same techniques used thousands of years ago are still in use today, in fact.
Bronze is an alloy made by melting copper and tin in varying proportions, but the resulting metal is easily worked and melted, does not rust and has a smooth finish. The ability to be colored artistically using chemical treatment combined with the ease of use makes bronze an ideal medium for many artisans.
The earliest method of making bronze sculpture was to use solid masses of bronze, but later artisans developed the lost wax casting method, which enabled the artists of the time to develop larger works of art, and produce the bronze sculptures faster.
About a thousand years ago, artists began using the lost wax casting method to create their masterpieces, and has been used by such renowned artists as Donatello, Rodin, Remington, and Russel, to name a few. The process of lost wax casting allows artists to produce as many works of their art as they feel fit, and while no two pieces of bronze sculpture are the same, all bronze made from the same mold is still original artwork.
Many famous sculptures belong in the public domain, and can be recreated in bronze using the lost wax casting method process to put a piece of history in your home or landscape project, at an affordable cost.