Saving archaeological iron using the Revolutionary Preservation System

Over the last few decades much research has been devoted to the removal of chlorides from and the stabilization of iron objects after excavation. Once this treatment is complete, iron artefacts are generally examined briefly by researchers and then passed to the collections manager. These materials represent structural hardware, tools, weaponry and, occasionally, decorative objects. They are sparsely represented in exhibit spaces and therefore usually occupy the "dead storage" areas of a museum or university laboratory. Often forgotten, iron objects generally turn to dust during their years of storage. For the past 12 years, researchers at Memorial University of Newfoundland have been uncovering the archaeological remains of one of Canada's earliest English settlements. George Calvert, later Lord Baltimore, established the Colony of Avalon in 1621. The site has been occupied almost continuously since then. More than one million artefacts have been excavated with approximately 20% of the assemblage made of iron. Realizing that treated iron in storage was re-corroding, fast intervention was needed to prevent further damage to the objects while preparing a re- treatment strategy. Our solution was to bag all re-corroding iron in RP/ESCAL enclosures. The Revolutionary Preservation (RP) System is an airtight packaging system. It was purchased to store items in an oxygen-free, low relative humidity (RH) environment thus preventing further corrosion until they could be re-treated. This paper outlines the authors' observations and experiences in bagging hundreds of fragile iron artefacts. In addition, preliminary results of an accompanying research project studying 150 building nails stored under a variety of conditions will be described.