The Lost-Wax Bronze Process

African Bronzes

In the 1660's, the first dutch explorers of the west coast of Africa described the extraordinary kingdon of Benin. They were particularly impressed by the plagues and bronze works created by Benin craftsmen to decorate the Oba's palace. The Benin portraits, usually of royal figures, were cast by the lost-wax process, which is described here. This head of the Queen Mother is re-created by the traditional method.

Tools needed: Sharp knife to trim, Bone Moulding Tool, Metal moulding tool.

1. MAKING THE CORE:

The Core, a mixture of Loomy soil (clay, silt and sand) and water, is built up from the base gradually. Each stage is allowed to dry so it will be strong enough to support the weight above. The core is then covered with a 0.1 inch layer of beeswax, which is the eventual width of the bronze.

2. MOLDING THE WAX:

Having completely covered the core with beeswax. the craftsman begins to etch the pattern and decoration with a molding bone. The color of the wax varies according to the diet of the bees that make it.

3. SEALING THE MOLD

The head (etched wax) is now covered in the same loomy mixture that formed the core. This is done in three layers. The first, the layer nearest the head, has to be very well worked and smooth, and is left to dry thoroughly. The other two layers are put on to give support and strength to the mold. String is put between the last two layers to hold the mold in position incase it breaks while being fired.

4. READY TO FIRE

When the head has been completely sealed with the three layers of loomy soil, it is ready to fire. Sticks are put in all over the head to hold the mold in position once the wax has melted. The mold is either surrounded and fired above ground, or put in a pit and wood arranged around the head is set on fire.

5. FIRING THE MOLD:

The wood burning around the mold causes the wax to melt, and it runs out through a channel in the bottom of the mold. This created a vacuum where the wax has been. When all the wax has run out, the hot mold is buried upside down in the sand.

6. POURING THE BRONZE

The bronze is now heated till it runs freely. The next stage is a crucial - and dangerous - part of the process. The orange-hot bronze is carefully poured into the upside-down mold, where it fills the gap left by the wax. The mold is left in the sand to cool down until it can be handled. It is then dug out and the outer layers broken off with a hammer to reveal the newly cast bronze head beaneath.

7. FINAL TOUCHES

The head is now left to cool. The the base is cot off with a shape blade. Next the artist digs out the core, using a hammer and chisel. The loomy soil will come out easily from the now blackened core. This difficult method of casting made possible the creation of very delicate bronze works of art.