Conservation of a cast zinc sculpture

Alexandra Klingelhofer and Gary Blackburn

Abstract

Cast zinc was a popular 19th and early 20th century medium for decorative sculpture, but its conservation is problematic. American ironwork and zincwork companies produced a wide variety of figures and decorative elements for advertising purposes and for the embellishment of public buildings, cemeteries, etc. These sculptures are subject to severe structural deterioration that causes complex conservation problems and requires diverse treatment strategies.

This paper describes the treatment of a larger-than-life cast zinc sculpture of an eagle with wings outspread, its claws grasping branches resting on a rock. Based on documentary evidence, the eagle was purchased around 1858 and stood on the roof of a newspaper building from 1858 to 1881. After a period of private ownership, it was returned to newspaper ownership, moved three times between 1938 and the present, and subjected to several restorations.

Examinations in 1987 and 1988 proved the eagle to be in extremely poor condition. On site, it was held in position on an exterior ledge by cables and a steel bar bolted to the wings and secured by brackets to the building wall. Open cracks and losses had allowed rain, ice and snow to enter the body cavity causing serious structural damage. The bracket, cables, and an internal iron support bar prevent the complete separation of the sculpture into several pieces.

The treatment included the creation of a stainless steel interior armature and support system; filling of losses and cracks; gilding and painting; and the reinstallation of the sculpture in an interior location.