Chemical Composition: ICP-MS/AAA data from sample, Leaded Bronze:
Cu, 80.48; Sn, 7.99; Pb, 10.95; Zn, 0.144; Fe, 0.14; Ni, 0.02; Ag, 0.05; Sb, 0.08; As, 0.14; Bi, less than 0.025; Co, 0.005; Au, less than 0.01; Cd, less than 0.001
J. Riederer
Chemical Composition: Plaque
XRF data from Tracer
Alloy: Leaded Bronze
Alloying Elements: copper, tin, lead
Other Elements: iron, arsenic
K. Eremin, January 2014
Technical Observations: The patina of the panels is green. In the case of 1992.321, the patina is dark green. Raised corrosion products and burial accretions are present at areas of the back surfaces. Inlay metal is red.
The surfaces are in very good condition, although the small areas of inlay are lost. Slight planar distortions are present in all of the panels. The brittle fractures at one end of each piece appear old, probably dating prior to burial.
Section 1992.317 is unfinished at the edges, where the others have leaf patterns. This panel shows how the general contours of the leaf decorations were incised directly in the wax model prior to casting the bronze. After casting, a small punch was used to mark off even intervals related to the elements of the leaf patterns. The leaf elements were then punched into the metal with both flat and elongated punch tools (see detail images for 1992.316 and 1992.320). The copper alloy inlay, which presumably was different in color, was hammered into incised lines cut with a small straight chisel. The back surfaces of each panel have coarse diagonal scrape marks related to cleaning and smoothing the surfaces after casting. A 6-mm width down one long and one short edge at the back of each panel was scraped further, obscuring the coarse diagonal marks. Green and gray corrosion products along these edges appear to be a form of solder, presumably lead based, which may have assisted in securing the panels.
Four of the panels, 1992.317, 1992.318, 1992.319, and 1992.321, were examined to see if there are any joins at the breaks. None of these fragments join to one another.
Henry Lie (submitted 2002)