Typically the copper oxhide ingots are highly pure (approximately 99 weight percent copper) with trace element content of less than one weight percent. The few tin oxhide ingots that have been available to study are also exceptionally pure. Microscopic analysis of the Uluburun copper oxhide ingots reveals that they are highly porous. This feature results from the effervescence of gases as the molten metal cooled. Slag inclusions are also present. Their existence implies that slag was not fully removed from the smelted metal and thus that the ingots were made from remelted copper.
Macroscopic observation of the Uluburun copper ingots indicates that they were cast through multiple pours; there are distinct layers of metal in each ingot. Furthermore, the relatively high weight and high purity of the ingots would be difficult to achieve even today in only one pour.
The porosity of the copper ingots and the natural brittleness of tin suggest that both metal ingots were easy to break. As Bass et al. proposes, a metalsmith could simply break off a piece of the ingot whenever he liked for a new casting.