Experience of studying, restoring and conserving 18th century copper alloy objects covered with enamel with silver overlays

The collection of the Solvychegodsk Museum Reserve contains church utensils dating back to the 18th century, made using the hot enamel technique with silver inserts - lamps, frame parts, and an icon. Presumably they were made by craftsmen from Solvychegodsk or Veliky Ustyug. The items have a similarly condition: cracks and chips in the enamel, loss of silver overlays, weak adhesion of copper to enamel, deformations and corrosion of copper alloys. Together with restorers from the metal restoration department of the State Research Institute for Restoration, a basic method for restoring the items was determined, which was successfully applied when performing restoration work with some individual modifications for each item. As a result of the work, research was conducted on the history of the existence of objects, technological manufacturing techniques used by 18th century craftsmen, including the manufacture of a copper base, the application of enamel, the fusing of overlays, and the firing of objects. It was determined that the base was made using the punching technique, then the object was covered with enamel. In the penultimate firing, the overlays were fused, and in the last firing, transparent colored enamel was applied to the overlays. Methods have been developed for correcting deformations of objects with enamel coating, complicated by the fragility of the enamel coating, cleaning from dirt and oxides, using acids and salts that react little or do not react with enamel coatings; strengthening of enamel and silver overlays, conservation of objects and their further storage.