How were medieval mace heads cast? Side note to technological analyses of find from Niebieszczany in south-eastern Poland

In the summer of 2016, an incidental discovery of a bronze star-shaped mace head was made in a forest situated in the territory of the village of Niebieszczany, South-eastern Poland. Its form and available parallels indicate that it could have been used during 12th–13th c., most likely in the 13th c. In previous studies on mace heads not much attention was paid to technological issues. It was assumed that they were manufactured during the 12th and 13th c. in the territory of Rus’, and have been exported from these territories to neighbouring areas. The comprehensive analysis of the bronze star-shaped mace head from Niebieszczany provided new conclusions concerning the manufacture of such artefacts. This mace head was most likely made in a multi-part wax model with two runners and a pouring basin that were joined on a clay core and then covered with clay in order to make a mould. In order to extract a ready artefact, such a mould had to have been destroyed after the casting. A simulation of filling and solidification using MAGMA software showed the process of filling the casting cavity of the mould and clarified defects that were recorded on the surface of the casting. Metallographic analyses (ED-XRF) revealed that the mace head from Niebieszczany was cast using a leaded tin-bronze of good quality, remarkable for its high resistance to heavy loads as well as to corrosion and abrasion. Meticulous observations showed that it was repaired using a bronze alloy with much higher contents of tin and lead.