The conservation of a late Renaissance tiled stove: a non-aqueous approach

A large 16th-century tiled stove at the Castle Hohensalzburg was treated after a severe episode of salt efflorescence, in addition to previous inappropriate interventions. Gypsum efflorescence causing blistering and spalling of the glaze became apparent after the object's installation in its current location in the year 2000. Scientific analyses indicated that the damage was driven by the prolonged presence of water after the installation and, consequently, any aqueous conservation treatments were deemed inappropriate. Affected areas were first consolidated in 2015 using a 5-10 percent (w/v) solution of PARALOID B-72 in acetone, which was successful in preventing further spalling. Subsequently, an eight-week conservation project was initiated in 2018. This paper presents the practical implementation of this fairly large scale, non-aqueous treatment, including cleaning, consolidation, and filling of hollow sections using putties made from polyvinyl butyral combined with glass microballoons, mineral fillers, and dry pigments