André Harvey Realistic Bronze Sculpture - Lost Wax Process

André Harvey’s bronzes are originally sculpted in clay, sometimes taking up to a year to make. In the same manner, the jewelry is sculpted directly in wax before casting into gold. Seeking quality and perfection, he personally works on each sculpture during the laborious and exacting bronze casting process. Each sculpture requires two working visits to the foundry to add the finishing touches needed in addition to the skill, and above all, care provided by the foundry.

1. Original clay (sometimes a year in
    the making).
2. Master mold covers the clay. Liquid
    rubber poured around clay hardens.
    Plaster keeps rubber in place.
3. Clay is removed, creating empty
    space. Rubber captures the
    details sculpted in the clay.
4. Hot wax is poured into the mold,
    picking up the details the rubber
    registered from the clay.

5. Wax hardens when cooled and is
    removed from mold. Harvey
    perfects, adds details. Pouring
    "gates" added.
6. The second ceramic mold covers
     the wax and hardens.
7. In oven, wax melts out of mold
    becoming "lost wax."
8. Molten bronze (2,200°F) is poured
    into ceramic mold.

9. Finishing Stage: mold hammered
    off, "gates" removed, metal
    welded, filed, sanded. Harvey
    perfects metal finishing.
10. Patina (Color) Stage: acids
      applied to heated bronze give
      rich colors.

11. Completed bronze.

Lost Wax Process (Cire Perdue)

Clay to wax to bronze—the lost wax process is a method for changing a sculpture made of soft clay into a harder material such as bronze. Changing the clay to bronze involves two molds for each sculpture. The first mold (made of plaster and rubber) yields a wax cast of the sculpture. The hand pouring of the wax determines the thickness, and therefore the weight, of the final bronze.

Immersing the wax cast in a liquid ceramic material forms the basis of the second mold. When hardened, the material can withstand the high temperature of the molten bronze. Next, the mold is heated until the wax melts out or disappears. Because the wax disappears, it becomes “lost wax” as the name of the process implies. The resulting empty space left by the lost wax in the second mold thus forms a "bucket"—shaped just like the sculpture—which is later filled with molten bronze.

The Master Mold (First Mold)

The first mold is called the master mold because it is taken from the clay original (figure 1). It is made of special rubber supported by a plaster shell (figure 2). The rubber registers the details sculpted in the clay (figure 3). When the soft clay sculpture is removed from the master mold (becoming ruined in the process) the resulting space is filled with hot wax (figure 4).

The Second Ceramic Mold

When the reworked wax is perfect (figure 5),it is encased in the second ceramic mold (figure 6). This mold is made of ceramic material because it must withstand the high temperature of molten bronze (about 2,200°F).

Next, the ceramic mold—with the wax cast inside—is placed in an industrial oven to melt out the wax (figure 7). Thus, the wax becomes “lost wax” as it melts out and disappears.

Molten bronze is then poured into the space left by the melted wax (figure 8). After cooling, the mold is carefully hammered apart to expose the bronze casting.

The pouring gates must be ground off, and the bronze perfected by careful welding, filing, grinding, and sanding (figure 9).

The Finishing and Patina Stage

At this stage, Harvey again visits the foundry to add the finishing touches that will make the bronze meet his exacting standards. When he considers the bronze perfect, the patina, or color, is added. This is hand-applied by heating the bronze and applying combinations of chemicals that control the color of the natural oxidation process (figure 10). Careful attention to the patina results in deep, rich colors which become a permanent part of the sculpture.

Finally, the edition number and the foundry mark are hammered into the bronze and the sculpture is waxed to protect the patina (figure 11).

The laborious casting process—a mold to make the wax, and a mold to make the bronze—must be repeated for each casting or sculpture part. André Harvey would not do otherwise. He is convinced that the casting times and energies involved—usually about eight weeks for a small sculpture—are well worth the effort. For once in bronze, the sculpture attains a permanency—a kind of immortality—that spans the generations and centuries. Perhaps, one day in the distant future, it may help explain to people yet unborn what it was like to live a life today.