Numerous methods for the stabilisation of archaeological ironwork have been developed over the years; and objects in our collections have been subject to a considerable number of them.
Recently an assessment of the stability of the iron collection at the Museum was carried out to try and answer the following questions: -
- Was our present treatment performing well? We currently desalinate iron using the Soxhlet apparatus then lacquer with Paraloid B72 (ethyl methacrylate co-polymer). This method has been employed at NMW for over 15 years. The performance of this treatment was therefore compared with that of other methods carried out on the archaeological collection in the past 30 years.
- Can the study of the performance of past treatment methods help development new procedures to deal with the problem of archaeological ironwork in the future? This survey would provide a true assessment of the performance of past and present conservation treatments used at the Museum.
- Does passive conservation (storage with desiccated silica gel) on its own manage to maintain or provide better levels of stability than active conservation methods?
Treatment records, X-radiographs and photographs exist in our archive from the 1970s, and this coupled with the fact that the iron has been kept in desiccated storage since then, makes the collection an ideal group of material to study the relative success of treatments. So far over 1500 objects have been assessed. It is hoped that this study will give an indication of the efficiency of past and present treatments used at the Museum and provide guidance when developing future treatment procedures.