- The Technology of Metalwork -
COMPOSITE STRUCTURES
The existence of two major structural metals, bronze and iron, seems to have stimu-
lated the inventiveness of many craftsman to produce composite structures. In the
western European Bronze Age opportunities were limited because, in effect, only
tin and the precious metals were available: gold inlays and tinned decoration do exist
but only in small numbers. In the Iron Age bronze and iron were combined for
functional purposes in the typical La Tene cauldrons, or for decorative purposes, as
in the bronze inlays in some iron spearheads (Raftery 199 I). Replacing the bottom
of a bronze cauldron with iron produced a vessel much better able to stand the heat,
while the colour contrast between polished copper alloys and iron is startling and
attractive, as recognized by the makers of Renaissance parade armour. Iron could be
bonded to other metals as well: iron pins could have tin heads while the use of iron
armatures in the tubular torcs at Snettisham required the bonding of gold to iron.
A large part of the greatly expanded use of bronze sheet at this time was due to its
application for cladding a variety of materials, organic as well as metallic. The late iron
age graves of Aylesford, Kent, or, for example, Goeblingen-Nospelt in Luxembourg
(Vidal 1976), show how elaborate wooden buckets were assembled and decorated
with bronze sheet. Similarly, bronze sheet was used in other icons of Celtic art such
as the Battersea and Witham shields, where it in turn could be inlaid with opaque
coloured glass (Stead 1985). In all these cases a functional purpose has been elevated
to give the appearance of luxury. Sheet bronze and other metals could be combined
in many ways and the variety of effects increased with time. In Britain this is particu-
larly true of the metalwork of the first century Be and first century AD and
perhaps even later in Scotland and Ireland. Examples include the combination of sheet
brass and tinned copper in the roundels from the Tal-y-llyn, Gwynedd, hoard (Savory
1964), and a torque combining differently patinated cast and sheet components from
Dinnington, Yorkshire, with the sheet formed round a lead core (Beswick et aI.I99I).
The mixing of metals extended to precious metals with, for example, combinations
of gold and silver; discussion of the use of metallurgy for decorative purposes is
continued below.
DECORATIVE METALWORKING TECHNIQUES
The decorative techniques of the Celtic smiths can be divided in to the mechanical
manipulation of the metal itself, from engraving to casting, the mechanical addition
of other materials such as enamel/glass inlays or bronze claddings, and the use of
metallurgical or chemical techniques for plating, etching and patination. The first two
of these are well-known elements of Celtic art but the third has seen much less study
and, because of the limited space available, will be the topic dealt with at greatest
length here.
The mechanical decoration of bronze can be split between three categories, the
first involves the removal of metal, for example in engraving (Lowery et al. 1976).
The classic example of this in Britain is the decoration of the mirror plates of the Late
Iron Age, where engraving techniques were used to produce the linear outlines of293