There’s a moment in every casting where you place a ceramic shell heated to 1,650°F into a pit of sand, pour molten bronze into the top of it, and then wait.
You don’t know for sure what you have until the shell comes off. Sometimes it’s a perfect casting. Sometimes it isn’t.
Skiagusta | Bronze, edition of 15 | 24″ × 30″ × 19″
Skiagusta is the largest bronze I’ve cast myself to date — a black bear running thirty inches in length and standing two feet high on a cast bronze plinth. The finished piece contains roughly 112 pounds of Everdur silicon bronze, cast in nine separate pours.
I like to have full control of every step in the creative process, so I don’t send my work away to be cast. From the original clay through moldmaking, wax, ceramic shell, pouring, welding, chasing and patina, I make the bronzes myself here at Beaver Brook Studio & Foundry in East Tennessee. Skiagusta pushed that process further than anything I’d attempted before.
The original was sculpted in Chavant oil-based clay, warmed in a low heat oven until pliable, then built up over an armature I fabricated after a lot of drawings and anatomy studies.
Getting the proportions right at the drawing stage saves you weeks later. A bear’s shoulder mass, the length of its limbs, and the way its weight sits over the front feet are the kinds of things you can’t fake once you’re in clay.
The clay original — the only version of Skiagusta that ever existed in one piece.
This is the part people are usually surprised by.
Large bronzes are normally cast in sections. There are practical reasons at almost every stage of the process.
The sections need to remain open enough for the ceramic shell to be built properly and dry completely between coats. Deep, enclosed forms can trap moisture and make it difficult to build a consistent shell — something you absolutely don’t want when that shell will eventually be heated to around 1,650°F and filled with molten bronze at well over 2,000°F.
There’s also the simple matter of handling. The larger and heavier a shell becomes, the more difficult — and dangerous — it is to move from the burnout oven, inspect, position in the sand pit and pour safely. Breaking a large sculpture into manageable sections gives you far more control throughout the process.
Skiagusta was divided into nine sections, including the head. Each section also needs its own system of sprues, gates, risers and a pouring cup to carry the molten bronze through the shell and feed the casting as it cools. All of that comes out of the same crucible, so every pour involves considerably more metal than what ends up in the finished sculpture.
My crucible holds roughly thirty-five to forty pounds of bronze, which is well suited to pours of this scale.
Before any rubber goes on, the original clay is carefully shimmed to create the separating seams that define those nine sections. Once they’re cast in bronze, the individual pieces are welded back together and chased until those seams disappear.
The rubber mold captures a perfect negative of the clay — every tool mark, texture and hair.
On its own, though, the rubber is far too flexible to hold its shape under the weight of the wax and the manipulation involved in slushing it. So each section is backed with a rigid fiberglass mother mold.
Then comes the messy part.
Out in the garage studio in full East Tennessee summer humidity, cicadas going and the camera lens fogging over, the mold gets separated along the seams and pulled apart.
Because this piece had significant undercuts, the only way to get the molds off intact was to sacrifice the original — pulling the clay apart from the inside so the rigid jackets could come away clean.
The clay bear is destroyed.
That’s the trade. At that point, the sculpture only exists in the molds.
Sections of mold. The clay bear didn’t survive the process.
Each rubber mold gets brushed with hot wax from a crock pot — about six layers applied with a disposable brush — until I have a hollow wax version of that section.
The wax is then chased to clean up the seam lines before being gated with red wax runners, sprues, risers and a pouring cup. These create the pathways the molten bronze will eventually travel through to fill the casting.
A gated wax. The red runners are the pathways the bronze travels.
Each gated wax is dipped in ceramic slurry and coated with silica sand.
Dip, coat, dry. Dip, coat, dry.
Nine times.
Layer by layer, that builds the ceramic shell strong enough to hold molten bronze.
The completed shells then go into the burnout oven. The wax melts out, leaving the hollow cavity that will eventually become the bronze, while the ceramic shell hardens at temperatures reaching approximately 1,650°F.
This is where everything you’ve done up to this point gets tested.
The shell comes out of the burnout oven and is bedded into the sand pit.
The bronze has been brought up to a pouring temperature of 2,050°F. The dross is skimmed from the surface, and then you pour.
It happens fast.
It’s probably the least forgiving 30 seconds in the entire process.
Then you wait.
Once the bronze has cooled enough, you break away the ceramic shell and finally find out what you’ve got.
Everdur silicon bronze going into the shell at 2,050°F.
Every section has its gates and runners cut away before being cleaned up by sandblasting and wire wheeling.
Then the puzzle goes back together.
I assembled Skiagusta in two main units — the feet and plinth as one, and the upper body as the other. Keeping the sculpture in halves initially makes it far easier to reach inside and properly chase the underside welds.
After that, it’s hours of TIG welding, chasing, banging and grinding, working every seam back until it reads exactly like the original clay.
The goal is that when it’s finished, you can’t tell where one casting ended and another began.
A final wire wheel and light sandblast prepare the metal for color.
Out of the shell and waiting to become one bear again.
For the bear, I wanted a deep, rich black.
The bronze is heated with a propane weed burner and liver of sulfur is applied to chemically react with the surface of the metal and build the black patina.
For the plinth, I wanted contrast, so I used cupric nitrate.
It creates the blue-green tones associated with naturally weathered copper — think of the Statue of Liberty. It isn’t exactly a forest green, but against the black of the bear, it’s a fantastic pairing.
Once the patina is complete, the bronze is waxed and burnished back on a buffing wheel to pull out the highlights.
And after all of that, Skiagusta is finished.
There’s something strange about watching a bear that began as drawings and a pile of clay finally standing in bronze.
By the time Skiagusta left the foundry, I’d handled virtually every square inch of him dozens of times — sculpting, molding, waxing, pouring, welding, grinding, chasing and coloring the metal.
Then, eventually, you have to let it go.
Skiagusta is now on view at the Grand Bohemian Gallery in Asheville, North Carolina, where he stands as the monarch of The Bear Necessities 1.0.
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