Identification key for adhesives used in conservation of ceramics and glass

During conservation-restoration treatments the conservator is often confronted with works that have already been treated. Generally, these previous interventions are not documented and the conservator needs to identify previously used materials to apprehend the object’s material history and to orient conservation treatments.Instrumental methods can be used to precisely identify the chemical nature of these materials. However, they require expensive analytical instruments which are usually only available within scientific research institutions. Microchemical spots tests, taken from qualitative analytical chemistry, have been made available to conservators as an alternative solution. These methods are extensively used to approach the nature of pigments, charges and binders, commonly found in art objects. The identification of historical and contemporary adhesives has been scarcely addressed in the scientific literature. Simple physicochemical tests, sometimes coupled to spot tests, have been used. Nonetheless, these methodologies do not systematically include the entire range of available test tools as to produce a broader, general approach allowing to accurately discriminate larger numbers of adhesives.The identification key proposed in this research is easy and inexpensive to use by conservators in their private workshop. The identification key was tested on various samples taken from ceramics museum objects (see practical cases) and proved that this identification key can be successfully employed on naturally aged adhesives.However we found that some parameters changed over time, such as appearance and fluorescence that’s why we based our research on more objective characteristics. It would be interesting to continue this research by studying the influence of aging on the response of adhesives to different identification key analyses.In a second time to observe the influence of other factors such as fillers and/or pigments added in some adhesives.