B-72 Fills for Glass
Comparing colored fill options with Victoria Schussler (left) and Lauren Fair (middle). Seminar taught by Victoria Schussler, Project Conservator at the Brooklyn Museum.
Any conservator will tell you Paraloid B-72 is an Object conservator’s best friend. The thermoplastic acrylic copolymer (70% ethyl methacrylate: 30% methyl acrylate) is soluble in a variety of organic polar and aromatic solvents and can be made in a range of concentrations. It is chemically stable, reversible and manipulate with solvents and heat, structurally strong, and optically clear.
Due to B-72’s mechanical and optical properties, it is used in conservation as a coating, varnish, consolidant, and fill material. It’s application as a cast fill material for glass was first proposed in 2011, but as Victoria demonstrated in this seminar, the application can include other inorganic and organic substrates.
The resin can be tinted with dyes or dry pigments before pouring into silicone molds to dry. The cast B-72 ‘blanks’ can be shaped using heat, textured, and/or painted depending on the needs of the object.
B-72 colored 'blanks' are made ahead of time in a variety of tonal shades and compared to the object after curing. This is due to the color shifts that may occur depending on the dye or pigment used, or as a result of solvent evaporation. New literature discusses methods for thermal setting fills to increase thickness. These methods were discussed but not attempted due to the brevity of the seminar.
To see this technique in action, see my treatment project for a recent acquisition to the Winterthur Museum’s collection an engraved and inked horn basket, c. 1828-1840.