Late bronze age bronzework in Britain is almost always cast close to its final shape and finished with a minimum of working. For a socketed axe this might simply mean removal of flash and sprue and then cold-working and annealing cycles applied to the cutting edge. For mass-produced items the annealing might be carried out at a low temperature and the area worked be very limited. The castings for ornaments and weapons might be cleaned up in the same way but in many cases finishing might consist entirely of grinding and polishing. The only important exceptions in the British Bronze Age to this casting-dominated technology were the cauldrons and shields (Gerloff 1991; Coles 1962) with their large-scale use of sheet bronze. The shields always show exemplary skill in handling this material but the cauldrons are much more mundane until the Llyn Fawr period when they became both more elaborate and finished to a much higher standard (see the introduction to this chapter discussing the Late Bronze Age). Indeed the general quality of all metalwork improved greatly at this time.
In the Hallstatt Iron Age in Britain, and elsewhere in Europe, the separation of bronzes into cast and wrought products intensified and wrought products increased in importance. As shown on page 5, the achievements of the sheet metalsmiths supported by the Hallstatt princes could be spectacular, for example the bronze couch and cauldron from the Hochdorf tomb, showing how they could produce large and durable structures in gold. There is nothing on this scale in Britain and even the cauldrons become simplified (Gerloff 1991; Meany 1990), but even so there are some striking items such as the dagger sheaths from the Thames Qope 1983). Pins and the first fibulae in Britain also point the way to the ascendancy of wrought or part-wrought products.
The introduction of La Tene styles to the British Isles made a revolution in bronzeworking. Apart, possibly, from highly specialized objects like the handle fittings of some cauldrons, there is no evidence for the use of cire perdu casting at any earlier date. Even a find such as the eleventh/tenth century BC hoard from Isleham, Cambridgeshire, with its host of thin-walled scabbard chapes, parade spearheads and ornaments, was based on the use of bivalve ceramic moulds, as is demonstrated by many flash lines round unfinished castings (Northover 1982). One possible reason for this was that beeswax of sufficient quality was very scarce. Although bee products are known from the Bronze Age, it is possible that they are from wild or forest bees; some effort is required to refine beeswax from them, and the product from the domesticated honeybee may have been seen as essential. It may be coincidence but the earliest remains of honeybees from British sites are no earlier than La Tene either.
The freedom of modelling given by the use of cire perdu investment casting liberated the bronzesmith. Casting by means of piece moulds never achieved the fantastic skill and three-dimensionality that it did, say, in China and it was only the new technique that permitted anything similar. Initially the most complex shapes were small, as in the fibulae, and larger, ornamental castings still tended to be relatively two-dimensional. For small, flat items simple bivalve moulds, often of stone, remained in use (e. g. Savory 1976: 104). One of the greatest expressions of this is the openwork bronze castings designed to ornament a wooden jug from Brno-Malomefice in former Czechoslovakia, a work so expressive of Celtic art that part of it was used for the cover illustration of the catalogue for the great Celtic exhibition in Venice in 1991 (Tanzi 1991; Meduna and Peskaf 1993). Lesser pieces, such as highly complex armlets, appeared in many parts of the Celtic world and continued to develop in areas as remote as Scotland until the second century AD. In Britain the most typical products of Celtic casting must be the many elements of horse harness which allowed the smiths to show all their decorative skills.
Although the basic elements of the casting technique remained the same, the technology did gradually evolve with time, sometimes in surprising ways. Crucibles from about the fifth to third centuries BC were deep, narrow cups with a thick handle; they were placed in the hearth with the draught directed at their base so the exterior became heavily slagged while the charge was quite well protected from oxidation. There was then a change to a shallow triangular type without a handle, characteristic of the industry at Gussage All Saints already mentioned. Here the draught was directed at the rim of the crucible, which became heavily slagged. Certainly it was possible to melt small charges of metal very quickly in this way but this had to be balanced against the considerable losses of metal through oxidation. From the first century BC new types, generally in the form of hemispherical bowls with pouring lips, became standard in the south and gradually spread northwards over the next century or so. This slow spread is seen with some aspects of iron technology as well and a series of isochrones can be drawn across Britain to chart the adoption of several techniques. Moulds changed as well with developments in the provision of runners and gates. The Gussage All Saints terret moulds from the late second to early first centuries BC have a single runner serving a single terminal, while those from Silchester of a century later have two, one for each terminal. The Silchester moulds also show how multiple matrices were included in one mould flask. Another odd feature at Silchester is that the matrix surfaces are not smooth but have a ribbed pattern; the rough surface would only have increased the work of finishing the casting unless it was designed to provide a substrate for some form of cladding (Northover unpublished).
World History
