Bees for Development :: Lost wax casting

1. The artist forms a solid mass of clay and allows it to dry in the sun until it is very hard. The shape of the clay needs to be roughly the shape of the item to be created. The item being made here is a model fish. Once the clay has hardened a thin layer of beeswax is fitted around it.

2. The artist moulds the features from softened beeswax working on an oiled board. Fish scales are represented by intricate spirals made from long, thin rolls of beeswax. The artist keeps the beeswax soft while working by occasionally warming it near a fire (but not too near!). The parts are applied to the wax model of the fish's body, and the model hardens.

3. Some more clay is now prepared and reinforced with cut burlap (sacking) pieces, rice husks or straw for added strength. A rod-shaped piece of beeswax about 2 cm in diameter is attached to the fish. This will serve as a spout to drain the beeswax out and to then allow the hot metal to enter. The reinforced clay is packed tightly around the fish and the rod. Using the clay a shallow bowl with a 2 cm hole is moulded at the end of the beeswax rod.

4. The clay-covered beeswax form is now placed in the sun for two days to harden. After this it is then put on a grid above a charcoal fire in a pit that is two feet deep. The fire is insulated with large scraps of metal. Its intense heat is enhanced by the constant pumping of bellows made from welded pipes and animal skin.

5. The worker waits until it becomes clear that the wax is melting. The figure is then lifted from the fire with long metal tongs and turned upside down. About half the beeswax can be drained and saved for future use.

6. An odd assortment of metal pieces collected by the family serves as the "bronze". All the pieces are broken into small, manageable chunks. Workers use trial and error to determine the weight of metal required to produce a particular object. It is always better to have too much metal than too little.

7. The metal chunks are placed in a deep bowl made of reinforced clay. This bowl containing the metal is now attached to the clay mould, and it is allowed to harden in the sun for a day. The mould is then placed in a fire with the bowl downward. After about seven hours, the sound of metal can be heard sloshing inside: the metal has liquefied.

8. The form is lifted from the fire and turned upside down. The liquefied metal flows down through the spout into the mould.

9. After cooling, the clay mould is broken away. The bronze fish emerges and is Ieft to cool completely. The metal spout is removed and rough surfaces are filed smooth. The filing gives the surface a shiny finish. Some workers prefer an antique finish - painting the surface with burned millet stalks that are ground into a powder and mixed with water. After the sixth coat, the bronze is buffed with a soft cloth until shiny.

Lost-wax casting: a practitioner's manual

by W Feinburg (1983) 74 pages" Paperback.

This manual has been written for craft workers and people with limited money, and is based on the author's experience of working in countries where the ideal materials and equipment are not always readily available. The manual is designed to encourage resourcefulness in building equipment, and to stimulate new interest in this valuable technique" This manual is available from Bees for Development.

[Bees for Development Journal #27]