The Process of Lost Wax Casting for Bronze Horse Statues
Step 1 Clay Model Making
our artists team make a clay model at first, which is 100% based on customers’ request.
Step 2 Silicon Rubber Mold
This step is by far the most critical. All the detail which appears on the bronze sculpture must be captured in the mold. The mold (depending on the size of the sculpture) is cut into sections for casting.
Step 3 Wax Making and Chasing
Molten wax is poured into the mold to form layers of wax. This wax model is an exact duplicate of the original casting. Then the wax is pulled from the mold and hand chased (re-detailed) by a skilled artisan. Although the artist reproduces the original artwork, each piece may slightly differ from the next.
Wax rods (gates) and pouring cup are attached to the wax casting in just the right positions. This will assure a full pour.
Step 4 Ceramic Shell Making
In a temperature controlled climate of 72 degrees Fahrenheit, the wax casting is dipped into Investment liquid several times. On the first dip a fine powder is applied. On the next dip of course, ceramic sand will be applied. This step is repeated several times, each increasing the coarseness of the material to create the ceramic mold. Between each dip, the ceramic layer must cure (dry) before another layer can be applied.
Step 5 Burn-Out and Casting
The ceramic shell is placed in a kiln and fired. The shell bakes and the wax is melted (lost) from the shell. This creates a hollow ceramic shell mold. Thus the term “Lost Wax.” Immediately the molten bronze is poured into the shell. At the time of pouring, the bronze is 2100 degrees Fahrenheit.
Step 6 Shell Removing
After the casting has cooled several hours, the shell is carefully broken away leaving the unfinished bronze.
Step 7 Welding & Chasing
with their finest welding&chasing skills, our professional craftsmen assemble the pieces together and show all details of original for us.
Step 8 Patina
According to customers’ requests, we make unique and art-quality patina which can stand for tens of years.
standing-horse-statueRelationship between bronze and lost wax technology
Bronze is typically the material of choice when a sculptor chooses to execute a work in metal. Casts require less support than most other mediums, are less prone to fracturing, are more easily reproduced, allow for the execution of finer details, and can be assembled in stages. As a result, ancient cultures across the world, from the Mediterranean to Southeast Asia and sub-Saharan Africa, developed methods of creating cast bronze sculpture at various points in history.
Bronze’s largest “weakness” is it’s inherent value as a material. Throughout history, many bronze pieces have been melted down to recover the raw metal itself, which would then be recast as weaponry or to create new sculptures if a piece had fallen out of favor. It is estimated that between 40 and 60 percent of modern European bronze sculptures made before the First World War have now been lost. The decimation of ancient sculpture is even greater.
While other techniques, such as hammering, have been used to mold bronze into various forms, “lost wax” casting has been the dominant method for much of history. The ancient Greeks were considered to be the original masters of this technique, as they were the first to create life-size pieces using this method. Many marble statues from western antiquity are known to be Roman copies of original Greek bronze masterworks, very few of which survive to this day.
The technique used in the creation of bronze sculptures has changed very little since Antiquity. The sculptor begins by fashioning the subject in wax, then covers it with clay, pours on the bronze, an alloy of copper and tin, then breaks open the terracotta, leaving only the bronze object behind. Highly valued by sculptors, bronze is a robust and resistant material that fairs well outside. Using wax to create the initial mould allows for a high level of detail on the final sculpture, unlike steel sculpture. Certain nuances in colour can be produced through the use of patinas.
The lost-wax technique is the most common technique for creating bronze figures and sculptures. Though the exact process varies from foundry to foundry, the technique has been relatively standard since its first use in c. 3700 BCE. The artists begins with a model for which a mold is made. A soft material such as silicone is used for the inner mold, which must be malleable enough to produce an exact negative of the original object. The outermold is rigid, often made of plaster. Molten wax is then poured into the mold thinly coating its inner surfaces. After it has cooled the wax is removed from the mold and ‘chased’ – perfected to remove any flaws or evidence of casting – wax
rods are added to form channels through which the molten bronze can flow and gas can escape. A rigid cast, again often plaster, is built around the wax mold and the entire object is fired in a kiln. This both solidifies the plaster and melts the wax which drips out of the mold through the channels. This leaves a prefect negative of the artist’s object into which the liquid bronze is poured.
After it is cooled, the casting is removed from its plaster mold, the bronze which formed in place of the wax rods is removed, and the surface is ‘chased’ once more, polished, and sealed. A well-cast bronze sculpture is weatherproof and extremely durable.