The Benin bronze casting process has come of age. However, it is not quite certain how the Binis became aware of the utilitarian or practical benefits of the bronze. Nonetheless, it is said that they sourced their bronze (which is usually an alloy of copper, tin, sometimes small quantities of other metals) from places like Songhay Empire, Western Sudan, etc., and much later from the Portuguese, with whom they established trade relations. Their fortuitous contact with the Portuguese made the brass manillas readily available and paved the way for the mass production of the bronze sculptures.
But with the advent of trade liberalization and globalization, production of these bronze pieces has increased and in most cases, the Benin bronze casting process has gone beyond the old methods of simply using the bellows to blow air into the smelting furnace. Nowadays, there is an innovation in the form of the electric blower, which is automated and much less arduous than the age-old bellows. More so, the Benin bronze casting process has witnessed the introduction of the angle grinder , an automated method of polishing, cutting, filing, and finishing bronze pieces ranging from medium to larger sizes.
The Benin artists of the bygone era had to figure out what best metal combination can be used for casting. They learned that it is easier to cast an alloy of copper and tin (bronze), copper and zinc (brass), or an admixture of copper, tin and lead (leaded bronze), than copper itself because the alloy or admixture tends to bring down the melting point, thus making it flow more easily than unalloyed or pure copper.
The Benin bronze casting process can be a bit fiery as the Benin bronze smiths have to endure the fervent heat emanating from the smelting furnace. The process involves creating a core of hardened sand powered by a refractory material or a furnace lining ( which is a lining consisting of material with a high melting point, that is used to line the inside walls of the furnace).
According to his taste and style, the Benin artist uses the beeswax to design or embellish the core mould ( which is a likeness of what is to be made ). This core mould work is held in position by pins or spikes in order to maintain the space when the wax is melted out. The runner, which is something made of wax is placed on the bees waxed model. A space or hollow is created on top of the runner. The purpose of which, is to allow the molten metal penetrate inside or around the mould work. A layer of red sand is used to cover both the waxed model and the runner . The entire mould work is then firmly held or banded together by some pieces of wire, so that the mould work is not destroyed while it is in the fire or furnace. It is transferred to the smelting furnace, where it is allowed to properly heat up for up to four or five hours. Thereafter, it is taken out of the smelting furnace and buried in the ground. Following this procedure, a crucible or melting pot is used to pour the molten metal into the runner channel which flows through to occupy the intervening space within the mould work. This is when the fiery molten metal melts out the wax or beeswax to take its place. Thus, the bronze object is made. This explains why it is called the lost-wax process, because the wax got lost in the process of making the bronze work.
Over a period of time, the bronze object becomes patinated ( acquires a patina – A fine coating of oxide, whose colour usually looks like green tinted with grey , covering the surface of the metal ). The patina usually gives the bronze piece an antique appearance, and this is what seems to appeal most to quite a number of art collectors and even lovers of art.