Grinding and polishing has always been the finishing process of all kinds of crafted goods. By burnishing, a surface becomes smoothed and an edge sharpened. Polishing gives an object a nicer look and only then the right finish. In certain...
moreGrinding and polishing has always been the finishing process of all kinds of crafted goods. By burnishing, a surface becomes smoothed and an edge sharpened. Polishing gives an object a nicer look and only then the right finish. In certain cases good polishing can also prevent rapid corrosion, as can be observed on the surfaces of finds of Roman metal mirrors.
The grinding and polishing abrasives presented in this book were more-or-less easily available to prehistoric and antique man. If he really actually did work with them can only be proved without doubt in a few cases. This study demonstrates how efficient the different abrasives are and therefore how probable their use in ancient times was. Synthetically made polishing agents, such as corundum, were not yet in use, unlike some side products of early indus¬trial production like tile powder from burnt clay. I confine myself here to grinding and polishing agents which could be useful in the manufacturing of all metals known in an¬tiquity. Most of the abrasives could of course also be useful in the processing of stone (from marble to precious stones), bone, antler and wood, but our experiments and experience in the field and in the laboratory focussed on metals.
When thinking of “natural” grinding and polishing agents, mainly sandstone, quartz sand and maybe natural emery spring to mind. Old handbooks for craftsmen and workshop equipment – plus a very few sources of inform¬ation from antique authors – deal with many other substances which could either be used for sanding or for polishing. These I obtained from natural deposits and from collections, processed them for grinding or polishing and tested them on copper, bronze and brass in line with “Experimental Archaeology”. Originally the aim was to define differences in the microscopic traces which the various abrasives leave as characteristic marks on the small metal sheets, and so to obtain information as to the abrasives used on antique finds. This proved to be impossible mainly because the marks left behind by grinding are primarily affected by the particle size of the abrasives and not by the materials themselves.
Apart from grinding blocs and pulverized polishing agents, grinding and polishing tools such as files, scrapers and burnishers are also examined. Files and hones have already been dealt with in length in many specialist monographs and therefore do not need to be extensively discussed here. On the other hand, the frequently used scrapers, which played such a dominant role in antique metalworking, correspondingly merit a far more in depth examination.
In the archaeological context we rarely find evidence of sanding or polishing materials, because only in excep¬tional cases can they be identified and specified. The num¬berless hones are the exceptions. It cannot usually be determined whether they indicate ancient metalworking or whether they were used for working other raw material. This is only possible when hones are found within a specific metalworking context. However, evidence of traces of metals on brick disks from Augusta Raurica (figs. 46,1–3; 47) shows that by implementing systematic surface analysis on hones, metals also in use in metalworking may in the fu¬ture also be identified. Even with the help of modern analytics, grinding and polishing powders will still be hardly identifiable (examples figs. 102 and 107). Further archaeological research must produce well documented evidence to prove as to whether the abrasives tested and discussed here were all used in times of antiquity or not.
In this spirit, it is to be hoped that archaeologists will examine even the most vague traces of these unimposing raw materials of many craftsmen, because such evidence will help us to a better understanding of past production technologies and of the workflow leading to the finished object.
(Translation Julie Cordell)