Adriaen de Vries's bronze casting: direct lost-wax method

Using Adriaen de Vries’s stunning 17th-century sculpture Juggling Man as an example, this article examines the laborious process of creating a bronze sculpture with the direct lost-wax method. This technique, used since antiquity, involves preparing a wax model over a clay and metal core, and ultimately replacing the wax with bronze to create the finished artwork. One reason De Vries chose to cast the Juggling Man and many of his other sculptures using the direct lost-wax method is because this procedure produces one unique bronze cast of an original sculpture. The term casting refers to the process of pouring liquid hot metal into a hollow three-dimensional form, also known as a mold, and allowing that metal to harden before removing it from the mold.

Adriaen de Vries was a celebrated late-Renaissance sculptor who was active as an artist from the 1580s until his death in 1626. He was born in The Hague, Netherlands, went on to train as a sculptor in Florence, Italy, and ultimately became the court sculptor for Holy Roman Emperor Rudolf II in 1601. After his service to the Emperor, who died in 1612, de Vries produced many commissioned works for wealthy landowners and royalty of Northern Europe. His remaining artworks, which are mostly figurative bronze sculptures, include portrait busts, statuettes, tombs, and fountains.

The Juggling Man is a strong example of de Vries’s interest in depicting the human figure in suspended instances of motion. The figurative sculpture is a nude male posed in action with small plates balanced in each of his hands. His pose is lively and expressive, with his right hand and leg raised slightly to suggest movement and create overall balance in the figure’s composition.

The Juggling Man figure at the left reveals a distinct S-curve shape, demonstrating the complexity of the juggler’s balancing act and enhancing the active appearance of the work.

Sculpting the Juggling Man was a multistep process with three main phases:

1.   Modeling

2.   Casting

3.   Chasing

De Vries began the modeling phase by first building what is referred to as an iron armature. In this case, an armature is the support structure that serves as the skeleton of the sculpture.

Making the armature required blacksmithing skills in order to heat and hammer the heavy iron into the desired shape. By examining x-rays of the Juggling Man, Getty researchers learned that de Vries formed one long piece of iron into an inverted U-shape, as seen in the replication at the left, and affixed smaller wires to it as support for the arms and head.

After forming the armature, de Vries then added clay to the metal frame in order to form the inner core of the sculpture, as seen at the left. When completed, the core was heated in an oven to thoroughly dry it.

Once the core was prepared, the artist modeled the figure in wax over the core until it reached its final form, with de Vries smoothing the wax surface and adding fine details using hot metal tools.

The hands of the Juggling Man were completely constructed of solid wax and attached directly to the armature. The replication of the Juggling Man model below indicates how the hands did not have a clay core but were instead rendered entirely out of wax.

To prepare the model for casting, two steps were then taken. First, several short iron pins, otherwise known as core pins, were inserted through the wax layer and into the clay core at key points all over the sculpture. The sprues, a complex network of solid wax rods, were then added to the outside of the model. A wax funnel, called the pouring cup, was then attached to the very top of the sculpture, as seen below. The pouring cup and sprues function as a circulatory system, allowing hot metal into, and gasses out of, the mold.

The wax model with its attached sprues would then be completely covered layer-by-layer in a mix of clay and other natural materials, as seen above. This outer covering, called the investment, would eventually become the mold into which the bronze was poured.

The replication at the left shows a cross-section of the complete mold with the iron armature in the center of the figure enclosed by clay core, the outer wax layer of the model, the iron core pins, and the network of wax sprues and pouring cup all enclosed in the investment.

The second and most dangerous phase of production in the direct lost-wax method is casting the bronze. This process is completed in a foundry, which is a facility for pouring and casting hot metals. The first step of phase two is depicted below, where the investment is turned upside down and set inside a kiln to be heated. When heated, the thin wax layer and sprues melt away to create voids in the mold into which the molten bronze will be cast. The core pins act as braces, holding the core in place once the wax is melted away. The investment is then buried right side up to ensure safety during the pouring process.

Liquid bronze is heated in a furnace to around 1,700 degrees Fahrenheit inside a container called a crucible, and carefully transferred out of the furnace and poured directly into the investment’s pouring cup (see below). Once the metal has cooled and hardened, the sculpture can finally be removed from the investment.

The final stage of preparation involves carefully removing the investment, sprues, and core pins from the bronze cast, as seen below. After removing the investment, de Vries began the process called chasing by first chiseling and filing the sprues off the figure. The iron core pins were then removed, and the holes that the pins left in the surface of the bronze were repaired. He then cleaned off the blackened layer of oxides created on the surface of the bronze during the casting process.

The final steps in the chasing process involve finishing the fine details of the artwork, such as the facial features and hands, with specially shaped iron tools. Finally, a patina is applied. In this context, the term patina refers to an applied translucent varnish that adds luster and enhances the appearance of the bronze. The original patina of the Juggling Man is gone because he was displayed outdoors for many years. His surface is now slightly green in tone due to natural oxidization, but the compelling composition and incredible fine details of this sculpture remain apparent, as shown in the image of the right hand of the Juggling Man below.

See how a bronze sculpture is made in the video Adriaen de Vries’s bronze casting technique: direct lost-wax method.