The conservation of tumbaga metals from Panama at the Peabody Museum, Harvard University

Scott Fulton and Sylvia Keochakian

Abstract

A grant awarded by the Institute for Museum and Library Services (IMLS) made possible a major conservation initiative for an important but very fragile group of tumbaga (gold/copper alloy) figurines from Veraguas, Panama (ca.1300-1500 A.D.). Approximately 70 of these small pendants required immediate attention due to unstable mount materials and restoration adhesives used in the 1930’s and 40’s. Cellulose nitrate (Celluloid) was identified as the primary mount medium to which the artifacts were adhered. The adhesive and consolidant was identified as a polyvinylacetal resin (Alvar). The predominant corrosion product was identified as basic copper nitrate.

Conservation treatment included methods that allowed the safe removal of the artifacts from their destructive Celluloid mounts. Earlier excessive applications of Alvar adhesive needed to be reversed or reduced and loose extant fragments required reattaching. The removal of basic copper nitrate corrosion products was effected on a local level using solvent gel techniques. Delaminated fragments of gilding trapped in glue and left behind on the Celluloid supports, was reclaimed by an unconventional backing technique using gossamer nylon and a cellulose ether adhesive. Each of the tumbaga figures was re-housed to promote safer handling for research and to facilitate access in storage.

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