If you are interested in the bronze casting process, you should be aware that the process is quite complicated. However, it is very rewarding.
First of all, you need to work on your sculpture. As soon as the sculpture is done it is divided into parts. If your sculpture is large you will need to use saws. However, if you have a small sculpture then you’ll only need to use a jewelers or an artisan saw. If your sculpture is a monument you will need to use a reciprocating saw.
Making a Rubber Mold
Make a rubber mold from clay. If you are creating a monument you will need to take a few months to make the mold. Prepare the mold using layers of cloth and silicone rubber. Now take a fiberglass backing or a plaster so that support is added to the mold. Now remove the clay from the mold.
Pouring Molten Wax
Now it is time to pour molten wax into the mold. This will produce a casting known as a “Wax pattern”.
Removing the Wax Casting
When the casting is cooled it needs to be removed. You will also need to hand-finish it so it matches the sculpture, you can use heat and dental tools. Now it’s time to use your wax rods and apply them to the wax pattern.
Shell Casting
Start the shell casting process. Do this by adding the wax image to a mixture. This mixture should contain slurry and silica sand. Please note, when making bronze castings you should be aware that this process can take at least a few weeks to harden.
You should come away with a rock-like substance. This substance should be capable of withstanding poured bronze.
Using an Autoclave
Once the bronze has been poured, it can be placed in an autoclave. This gets rid of the wax and it leaves a cavity in its place. Steam out the remaining wax and inspect it for cracks. Now it’s time to heat the bronze bars so they become a liquid. Fill the mold with molten bronze.
Hammer the Sculpture
Once the shell is cool hammer away the mold. Now you need to air blast the fine sand particles. This will remove any ceramic shell that has stick to the bronze.
Welding
Once all the sprues and gates are cut away you’ll need to weld the parts together. You will then need to re-detail them using air tools. Some parts might need to be reworked at this time. Now you will need to glass bead blast the sculpture so you have a smoother finish.
Treating the Bronze
The bronze now needs to be treated with acid. You can use an airbrush and a blowtorch for this procedure. The acid gives the sculpture the desired color. It’s now time to add up to 3 layers of protective coating. This will ensure the color is sealed. Weld steel pipes in the monument so they can be added into cement. Your monument is now ready to be installed.
While it can take years to perfect the bronze casting process you could be left with something very special.
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