MÉTAMORPHOSE OF A BRONZE SCULPTURE
From clay to bronze sculpture
Everything begins in the studio, with clay. Alain Choisnet models his works with a focus on simplicity and a natural quality. Each sculpture is conceived from the outset to engage with the viewer and ultimately be cast in bronze.
Once the work is complete, it is entrusted to an art foundry. The transformation into bronze then begins. Several specialised crafts are involved in bringing the model to its final form. The artist may intervene at different stages to preserve the original intention and ensure the desired level of quality.
From wax to metal: lost-wax casting
Used for thousands of years, lost-wax casting remains a technique particularly well suited to faithfully reproducing a sculpture. Bronze is an alloy of copper and tin, valued for its strength, durability and ability to reproduce the finest details.
The first step is to make a silicone mould directly from the original sculpture. When the shape is complex, the mould may consist of several sections. A plaster or resin shell is then added to prevent deformation. This high-quality mould is used to produce the strictly limited edition of the work.
The clay is removed and the inside of the mould is coated with hot wax. The wax, a few millimetres thick, will correspond to the thickness of the future bronze. Wax channels are added to allow the molten metal to circulate and gases to escape. The whole assembly is then filled with refractory plaster to form the internal core.
Once cooled, the wax model is removed from the mould and carefully retouched. The seam lines are corrected and any imperfections removed. New sprues and vents are precisely added, while small metal pins hold the core securely in place.
The work is then covered with several layers of refractory material to form the casting mould. In the kiln, the wax melts and drains away during the dewaxing process, while the mould hardens at around 600°C. It then becomes strong enough to receive the molten bronze.
The Birth of a Bronze Sculpture
Buried in sand to withstand the thermal pressure, the mould is filled with molten bronze heated to around 1,000°C. The metal replaces the wax and faithfully reproduces every detail of the sculpture. Once the bronze has cooled, the refractory mould is broken away to release it. The casting channels, now made of bronze, are sawn off. This mould can only be used once.
Next comes chasing, a crucial stage in the creation of a bronze sculpture. Excess material is removed, any porosity is repaired, sections are welded where necessary, and the surface is then polished. The bronze regains its natural golden colour.
The artist’s name, edition number, year and foundry mark are marked on the base, guaranteeing the authenticity of the work.
The patina: the final signature of the bronze
Rich in copper, bronze naturally evolves over time. To control this process, the sculpture is patinated using heat. The applied solutions react with the heated metal, creating a palette of shades ranging from deep browns and satin blacks to subtle greens and blues. The final colour depends on the oxidising agent used and the temperature reached.
A thin layer of wax or varnish is then applied to protect the patina and preserve its colours. After a final polishing, the sculpture reveals the full richness of its reliefs. It is then ready to be viewed, appreciated and passed on.
