archaeometallurgy

The casting of an aquamanile in original medieval technique has been a long term intention of mine. A year ago I made an aquamanile in the form of a lion that dated to the medieval period, however I did not have time to cast that particular aquamanile in a technique that can be considered medieval.- The model however was made with the techniques known to medieval artificers.  It was made according to Theophilus Presbyter’s description in his schedula diversarum artium , a 12th century manuscript on artisan’s techniques. Theophilus’ chapter 61 on the making of the cast incense burners provides all the necessary information, with which an informed reader can go ahead an produce a formidable bronze (or any other copper alloy) casting. This information was used to prepare the mould for the casting of this aquamanile. There will be an article shortly on how to make the mould.

Loam mould of the lion aquamanile. The loam mould consists of the same ingredients as medieval moulds.

Casting a medieval aquamanile

The mould was prepared from  loam and made three days before the casting. The wax model was molten from the loam mould over embers. The mould was subsequently fired with charcoal. The charcoal was allowed to burn down to the top of the mould and before it was charged again with fresh charcoal. This was repeated three time s, just as Theophilus tells us . The casting was accomplished through the feet; so the mould is placed upside down for the casting. It was cast with a quaternary alloy of copper, zinc, tin and lead. The alloy is CuZn13Sn8Pb2 and was prepared for the casting.

References

This is a hands-on experiential archaeology course in one of the most important Celtic hill-top fortifications in central Europe: The Heuneburg in south western Germany. On April 26/27 we are holding an intensive course on the archaeometallurgy of bronze with loads of information to go alongside the practical experience of casting bronze the ancient way.

It has been my main objectives to foster the first hand experience of metallurgical processes alongside the scientific study of past archaeometallurgical activities. Together with the Heuneburg Open Air Museum we are now busy  developing the Heuneburg Academy, where hands-on experience is thought of as an equally important aspect of archaeometallurgy, as is for example scientific archaeology or archaeology. Only through an transdisciplinary approach will we able to better understand our forebears.

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Image width 200 µm, PPL. Medieval copper smelting slag.
The first thing to do is to establish the number of different phases present in the sample. In this case there are five different phases.

If you managed to follow so far, you have now reached part seven part of the slag microscopy course. After sample prep, with find documentation, cutting, mounting, grinding, lapping and polishing we are now going to have a look at the tool to be used for the next sessions: the polarising reflected light microscope, also referred to as an ore microscope. Continue reading