The Conservation of Glass

Abstract

Cleaning is often done to improve the appearance of a glass. However, archaeological glasses should not always be cleaned as this can remove original material. Historic and modern glasses can often be safely cleaned, but must be evaluated individually. Repairing broken glasses is done using synthetic adhesives. Two different adhesives are recommended for the repair of glass: Paraloid B-72 and epoxy resin adhesives. B-72 is an acrylic copolymer and prepared as a resin: solvent solution. Epoxy adhesives are more complex thermosetting resins and require very precise mixing proportions. The advantages of B-72 adhesive include stability, reversibility, fast setting time and low cost. It can also be used as a consolidant for strengthening fragile or deteriorated glass. Epoxy resins are often used on clear, transparent glasses and for large structural repairs. All glasses should be stored in a well-ventilated and climate-controlled environment. The humidity should ideally be between 40 and 50%. Temperature can vary considerably, if it does not change the humidity. Historic and modern glasses can slowly deteriorate from high humidity fluctuations, but most archaeological glasses are less susceptible to this problem.