Metal and Patina: How the Surface Is Made

When the shell breaks away, the raw casting is visible for the first time. Foundry people call it the rough. That word is accurate. The surface carries seam lines, casting texture, and the slight imprecision inherent in any pour. The sprues that channelled the metal are still attached. What is sitting on the bench at this moment is recognisably the sculpture. But it is not finished. Not close.

What happens next takes longer than everything since the wax stage.

Stage 9: Demoulding

The ceramic shell is broken away by hand. Sprues and gates are cut off with an angle grinder and ground back flush with the surface. The rough is cleaned, inspected, and handed to the chasing department. This is the first moment anyone can see whether the pour was fully successful.

Stage 10: Metal Chasing

Chasing is the hand-finishing of the cast bronze surface. The tools are metal: rifflers, chisels, burins, abrasives of varying grades. The goal, as foundry tradition holds, is that the finished bronze should not look like it has been cast.

A chaser works across the entire surface, removing defects, sharpening edges, blending transitions, and restoring the detail the sculptor built into the original model. At Classic Art, each piece is chased individually by craftspeople who have worked in the foundry for years.

This stage takes longer than the casting itself.

It cannot be automated because it requires judgment. A machine can remove metal uniformly; a chaser reads the surface, understands what the sculptor intended, and knows when to stop. Those are different operations. The first can be programmed. The second cannot. This is the stage that separates a fine bronze from a reproduction.

Stage 11: Patination and Finishing

Patination is not painting.

The chased bronze surface is heated with a torch and treated with acid-based compounds whose exact chemistry and application sequence is part of the foundry's accumulated expertise. The colour is a reaction with the metal itself, not a layer applied on top of it. Heat opens the surface; the compounds penetrate it. The specific palette available depends on what the metal will accept, and that varies by alloy, surface geometry, and the judgment of the person applying it. No two pieces are identical.

A final coat of paste wax is buffed over the entire piece, sealing the patina and completing the work. Each finished sculpture is inspected against the foundry's quality standard before numbering and certification.

The sculpture is done. It has been through eleven stages, several weeks, and the hands of people who do this work every day. What it looks like now is what it was always going to look like, from the moment the sculptor finished the original model.