The cast bronze, smooth bore gun was fabricated at the Revere Copper Company, Boston, Massachusetts in December, 1862, one of five foundries producing ordnance for the Federal government during the Civil War. The gun, designed to fire a 4 ½” diameter twelve pound round shot was noted for its flexibility in both long-range bombardment and close range anti-personnel fire, made it the workhorse of all Civil War artillery. As a result, this type of field gun made up nearly 40% of the total artillery used by the Union and Confederate Armies. The bronze tube was fitted to a cast iron replica of the wooden and iron carriage sometime in the first half of the 20th century.
The cannon and carriage, while structurally stable, had been over painted with a black oil base paint. The bronze tube had been exhibited or stored outdoors for many years causing the development of an uneven green, copper sulfate corrosion layer and deep etching of the metal surfaces by acidic deposition and rainfall. The carriage, originally painted dark green and black, had areas of active iron corrosion and pitting of the cast iron components used in its construction. Large areas of paint had been lot on both the gun tube and carriage caused by flaking or wear from handing as visitors passed through the exhibition gallery.
The tube was lifted from the carriage and transported separately to the conservation facility. After documentation, the over paint was carefully removed from the carriage to determine the original paint scheme and color. Active corrosion on the replica carriage was mechanically and chemically stabilized and prepared for repainting. A portable work cradle was designed and fabricated to hold the bronze tube during treatment; upon completion the twelve hundred pound cannon was lifted and placed on the cradle. Paint samples were removed and retained for the museum’s records prior to chemical removal of the black, oil based paint. The barrel was found to have been deeply etched by “acid rain” which had occurred during years of outdoor display prior to museum acquisition. The bronze was polished, as per curatorial request, to return the Napoleon 12-pounder to an “in-use” appearance based upon period descriptions of artillery during the Civil War.