Some Island History brought to life: Bronze Smelting- the ancient method.
Here are some images from a recent Science Fair in Palma, courtesy of the Universitat de les Illes Balears (UIB). There were various displays on Marine and Environmental Sciences and also this wonderful demonstration of traditional bronze smelting. The fundamental process is largely unchanged since the Bronze Age.
It is of some interest to those of us who are interested in maritime history and who love traditional boats since bronze is a widely-used in traditional boat-building and the commerce in metals was fundamental to the development of maritime trade in the Mediterranean and perhaps beyond.
Bronze is an alloy of Copper and Tin. Copper Ore (Malachite) is found in Mallorca but not in large quantities. Tin Ore (Cassiterite) is not found here and was imported, probably from the Iberian Peninsula but it might also have been imported from as far afield as Turkey and possibly as far north as Cornwall, in the UK. (See Herodotus’ reference to the Cassiterides.)
The basic process for extracting the metal from both ores is:
· Heat the ore to separate out a metal oxide.
· Reheat the metal oxide in the presence of a carbon source (e.g. charcoal) to reduce the metal oxide to a bare metal, which liquifies in the heat of the fire and can be collected in a crucible, as shown in the images/videos.
· To produce bronze, all that remains is to melt and mix the tin and copper in a crucible, pour into a Mold of an appropriate shape, allow it to cool and then clean it before working to the final form. Note that quenching bronze to achieve the desired properties requires some skill as the effect depends on the impurities. It may cause fracturing, softening or make it more brittle. Presumably, this was a matter of trial and error for bronze-age metalsmiths, if they were unsure of the ore quality.
Ancient bronze artifacts found in the Balearic Islands, especially from the Late Bronze Age (1300–850 BCE), include ritualistic objects such as swords, mirrors, axes, and pectorales, often found in votive deposits. These artifacts demonstrate a mix of local and foreign influences, showcasing the islands' integration into the broader Western Mediterranean maritime network. A key example is the "Son Oms type" solid-hilt sword, which has a unique local design.
Types of artifacts found in the Balearic Islands:
Swords: Solid-hilt swords, known as the "Son Oms type," were a dominant artifact. They had a disc or rhomboid pommel and a slender blade, and were likely symbolic rather than for combat. One 3,200-year-old sword was discovered at the Talaiot del Serral de ses Abelles site.
Pectorales: These were an accessory worn around the neck; essentially a very large and decorative pendant.
Other objects included mirrors, diadems, and axes.
More recently, bronze has been (and continues to be) an important material for boat-building, due to its resistance to saltwater corrosion and its strength, which is close to that of steel.
Open-topped bag bellows
Pouring the Molten Metal
