Our Process

The Original

Many of our clients are artists bringing their original sculpture to our studio to have cast in bronze. The original is sculpted by the artist in their medium of choice, often clay or wax or sometimes plaster, wood or other materials. Some clients and patrons have our skilled in-house artists create an original for them, based on the client's vision and input at various stages throughout the process. From here the fascinating journey, involving the transformation into bronze, begins.

Mold Making

After thoughtful planning, wax vents and feeds are added directly to the original sculpture. In most cases, molds are created as two or more interlocking halves or multiple sections, depending on the size and shape of the original sculpture. Using various methods, urethane rubber molds with rigid outer support cases, called mother molds, are then created. Once fully cured, the rubber is carefully cut open and the original sculpture is removed. These molds are quite durable and may be used many times.

Wax Replication

The molds are cleaned up and hot casting wax is either poured in and dumped out or painted into the mold, layer at a time, until an ideal thickness is achieved. Once cooled, the hollow wax replica is removed from the mold. Using heat and various tools, the wax parts then undergo a process referred to as chasing. This includes cleaning up any flashing, parting lines or other imperfections that occurred when the wax was poured into the molds.

Spruing

Strategic patches are cut from the wax sculpture parts so that all sides, including are accessible in the coming steps. All of the parts and patches are secured to a central feed called, a cup or a tree, using sticks of wax called sprues. These sprues, resembling branches on a tree, act as additional feeds that will create channels for the bronze to flow into during casting.

Shell Dipping/ Investment

The trees are dipped into a ceramic slurry and then covered in an even layer of fine silica sand. This process is repeated several times, allowing the tress to dry between each dip. The result is a ceramic shell, about half an inch thick, built to withstand the heat of molten bronze. This investment shell, that has captured the finest details of the original sculpture, can only be used for a single casting. If multiple castings are desired, each one would begin again from a freshly poured wax.

Burn Out

This step is where the ancient practice of lost wax casting gets its name. Before we can pour bronze into the investment shell, we need to get rid of the wax. In other words, it must be 'lost'. This is done by placing them into a very kiln and allowing the wax to melt away. Once cooled, the shells are carefully inspected for hairline cracks that could cause castings to fail. Any cracks that are detected are patched, along with what we call 'pop offs' that were placed to allow wax to escape during burn out.

Casting

Silicon bronze ingots, placed in a crucible, are heated to approximately 2,000 degrees Fahrenheit inside a furnace. The crucible is lifted from the furnace and the molten bronze is poured into the preheated investment shells, filling the voids left by the lost wax. The bronze. Then re-solidifies as it cools.

Break Out And Assembly

The shell is then chipped and blasted away, using various tools and the sculpture parts are cut off of the trees using a plasma cutter. Now the sculpture parts are reassembled and welded together. Now in the form of bronze, the sculpture is chased once again, removing welding lines and repairing any flaws that occurred during casting.

Patination

Pagination is what gives the finished sculpture its unique look. Patinas, which also occur naturally over time, are achieved using heat along with an array of acids, sulfides and other chemical compounds. Wax is then applied to the surface, further enhancing and protecting the final. Finish.