Materials Conservation

W. Ryan Smith Removing Loose Surface Debris From a Cast Iron Artifact Following Electrolytic Reduction

The Cultural Resource Office can trace its very beginnings to archaeological materials conservation when the Archaeological Conservation Laboratory (CRO’s start-up organization) first opened its doors in 1994 following a contract approval with the U.S. Army Corps of Engineers (USACE) to perform the materials conservation of a large number of artifacts recovered from the wreckage of the U.S.S. Eastport. The Eastport was a Civil War ironclad gunboat which sank in the Red River near present-day Montgomery, Louisiana in 1864.

Our labaratory most typically performs electrolytic reduction treatments to preserve inorganic metal artifacts recovered from systematically investigated archaeological sites. Electolytic reduction is a process which uses an electrolytic cell and an artifat as a cathode. An electric current applied to the artifact stimulates oxidation and reduction, essentially “cleansing” the artifact of its corrosion and replenishing  its surface with a more stable metallic base. After reduction the artifact is brushed with tannic acid and dipped in hot wax for long-term preservation and handling solutions.

19th Century Cast Iron Artifact Recovered From Old Pleasant Hill, Louisiana Detailing Before and After Electrolytic Reduction Treatment. Photographs by W. Ryan Smith.