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Ever wonder what happens to an artifact after it is discovered? Many may go to a conservation lab like the Archaeology Lab in the National Geographic Treasures of the Earth gallery. Scientists work in conservation labs like this to research and preserve archaeological treasures using various tools and techniques.
As part of an ongoing collaboration with the government of the Dominican Republic, The Children’s Museum worked hard to preserve a verso—a small cannon that was mounted on a ship’s rail which could be swiveled around to aim at enemies—from a 16th century Spanish shipwreck. We asked Christy O’Grady, Exhibition Conservation Manager, to share a few details about the museum’s verso conservation efforts.
Pretreatment condition, 2014
Cleaning through electyrolytic reduction
Cleaning and stabilizing the verso required several years and a number of different treatment methods. One method, electrolytic reduction, helps to remove dangerous chlorides in the iron. Electrolytic reduction, or electrolysis, is a process that uses electricity in a specially prepared solution to preserve an artifact. The electrolysis makes it easier to remove the layers of sand, mud, and shells—known as concretion—that have built up on the verso itself.
While the verso was in electrolysis, we carefully monitored the chloride levels in the water to know when the verso was ready for the final stages of treatment. When the chloride levels dropped to a very low level we knew the verso was ready to be removed from electrolysis.
During the rinsing and heating process
Final steps: rinse and repeat
The last steps of conservation involved placing the verso into an insulated steel tub and conducting five alternating baths of cold and heated deionized water. These rinses, plus some final scrubbing, completed the cleaning of the verso and ensured that the harmful chlorides deposited by the sea water were removed.
We used around 800 gallons of deionized water to complete all of the rinses.
After the final rinse: deyhdration and sealing
After the final rinse, we dried the verso and applied several coats of a tannic acid solution that seals the metal and helps return it to its original black color. Finally, a coat of clear polyurethane was applied to help protect the verso from environmental factors like heat and humidity that could lead to the verso’s deterioration. This polyurethane coating acts as a protective barrier against such agents.
Application of tannic acid
Now that our preservation efforts are complete, the verso has been placed in a crate and will be shipped to the Dominican Republic. It will be displayed in a new museum there.
