Smithsonian Castle, Washington, District of Columbia

In the Smithsonian Castle gardens are two statues dedicated to prominent figures in the history of the Smithsonian Institution. The Joseph Henry statue, by William W. Story was unveiled on April 19, 1883 to commemorate the first Secretary of the Smithsonian. Commissioned to Leonard Baskin and unveiled on May 4, 1978, the Spencer Fullerton Baird statue pays tribute to the first curator of the Smithsonian National Mall.

The Joseph Henry statue exhibited deterioration typical of bronze that is under-maintained. Failure of the previous wax coatings and the resulting light green corrosion products from exposure were visible on the statue’s upper surfaces, while built-up remaining wax and brown and black corrosion products were present on the undersides and in folds and crevices, creating a stark contrast and resulting in an inconsistent appearance. The Baird statue, in comparison, was in relatively good condition, exhibiting failure of the previous wax coatings on upper surfaces, but only minimal corrosion.

In 2006, Conservation Solutions, Inc. (CSI) performed conservation treatments on both statues. The Henry statue was stripped of its existing wax coating using pressurized hot water; any remaining coating was removed using a combination of heat and solvent wipes. The bronze was then washed and waxed, as above. Mineral pigments were used in the wax mixture to help blend together the areas of varying tone, and provide a coherent appearance. The Baird statue received a gentle anionic detergent wash followed by a rinse with low-pressure cold water. The bronze was then heated and coated with a hot-applied wax mixture to help protect it from further deterioration. The statue’s granite base was treated using a nonionic surfactant and then a solvent-based gel stripper.

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