Our bronze sculpture awards, including both custom awards and pre-designed (stock) recognition awards, are created using the “lost wax” casting process. This time-honored production process has been used for thousands of years with very few changes, even extending into today. While there are many foundries that produce bronze sculpture, achieving high-quality bronze castings is not easy. To do this right is a very lengthy, labor-intensive process that requires the talent and expertise of skilled artisans; it is truly part science and part art.
Since each bronze sculpture award is individually handcrafted, each piece is “one of a kind” – no two sculptures are identical, even if they are created from the same mold. The idiosyncrasies of each custom-made bronze sculpture are part of what makes them true works of art, as opposed to just another common mass-produced award that will sit on a shelf, identical to many others.
Here Are The Steps Required To Create A Bronze Award:
- Step 1: Create a Model
The first step in creating a bronze award is to develop a model that will be used as the base design form for the award. Models can be created out of a variety of materials, but the most common are clay and wax. The size, complexity, and design of the bronze award all play a role in determining the optimal material to use for the model.
- Step 2: Create a Mold
Once the model has been finished, a mold is created by progressively coating the model with silicon rubber. Multiple coats can be applied to create a different thickness around the original model. Once the right thickness is achieved and the rubber hardens, an even harder plaster-like shell is applied to the outside of the mold to protect it. If something were to happen to the mold all subsequent castings would carry that flaw, so it’s important to properly care and store these molds.
- Step 3: Create a Wax Replica
Steps 1 and 2 are “one-time” processes. Once these steps are completed, each new bronze sculpture that is cast will begin the process at Step 3: wax replica creation. In this stage of production, wax is heated until it achieves a liquid-like consistency and then poured into the cavity (the hollow inside) of the mold. Once the wax pouring is complete and the wax has fully cooled and hardened the wax replica is removed from the mold. The mold is then stored to be used again as needed. Any imperfections in the wax replica such as bumps or divots are corrected (“wax chasing”), and the replica is now ready for the next step.
- Step 4: Prepare the Wax Replica for Casting (Spruing)
A “pouring cup” is attached to one end of the wax replica using a set of wax “spue lines” that serve as conduits for molten bronze to be poured into the sculpture, ensuring that the bronze is distributed evenly throughout the replica. Some of these sprue lines are created to release air that could be trapped when the bronze is poured, thereby minimizing imperfections and bubbles caused by the air pockets in the final bronze sculpture.
- Step 5: Coat the Wax with a Ceramic Shell (Investment)
The “prepared” wax replica, including pour cup and sprues, is dipped in a heat-resistant liquid called “slurry” and then a heat-resistant sand called “stucco”. This process is repeated several times, adding a new “coat” to the wax replica as each coat dries and another is applied. Once the slurry and stucco coats are complete and the material fully dries it becomes a hard ceramic shell, often called an “investment”.
- Step 6: Burn Out the Wax (Burnout)
After the ceramic shell is completely dry and hardened, it is inverted (cup and lines pointing downward) and placed in a kiln at approximately 1,800 degrees. The extreme heat in the kiln serves two purposes: 1) it further hardens the investment shell; and 2 the temperature in the kiln melts away the wax in the shell, leaving a cavity in the exact shape of the original model. This is where the term “lost wax” casting process comes from, as you have to lose the wax to end up with a final open cavity for casting.
- Step 7: Pour the Bronze (Pouring)
The ceramic shell is now placed in a sand pit with the pouring cup facing up. Bronze ingots are placed in a crucible and heated in a furnace to a temperature of approximately 2,200 degrees – at this temperature, the bronze melts into a liquid form. The molten bronze is then poured into the empty cavity and allowed to cool and harden. Once the bronze has fully hardened, the ceramic shell is broken away from the bronze award (“Release”), which is now in the shape of the original model.
- Step 8: Finish the Bronze (Finishing / Chasing)
The first step to “finish” a bronze award is to cut the sprue lines off the main body of the sculpture. Then the sculpture is sand-blasted to remove any extra bronze particles left-over from the pour. Any parts that were separately cast (as some larger pieces are made) are welded back together. Finally, the bronze award is ground (similar to sanding) using power tools and progressively finer grades of sandpaper-like material. This last step, called “chasing”, requires many hours of physical, labor-intensive, and finely detailed work.
- Step 9: Polish and/or Patina the Bronze
At this stage, the bronze sculpture award is either polished to a shiny finish (high-polished), or colored by applying various chemicals that oxidize the bronze. This coloring is known as the bronze award’s “patina”.
- Step 10: Mount the Bronze Sculpture Award on a Base
The final step is to mount the completed bronze award on a base.
Once you realize how many steps and how labor-intensive it is to cast a customer bronze award (not including the initial design phase) you can appreciate them as more than just recognition trophies, but instead as pieces of art made by master craftsman.