John Maine Sculpture No 4
Contemporary limestone geometrical sculpture by John Maine, 1970; Aston University, Birmingham
The sculpture was so heavily soiled that it was believed to be made of concrete rather than limestone. Thorough cleaning was required. Loose soiling was removed from the surface with stiff brushes. Moss was removed from the sculpture using wooden spatulas and soft plastic tools. The surface was then brushed to remove any remaining soiling. The bulk of the colonies of lichen growth were removed physically with soft plastic spatulas. Biocide formulated for limestone was sprayed onto the surface in order to eradicate the bio growth (algae, lichen etc.) that was covering the sculpture. Superheated stone steam cleaning system was used to remove ingrained surface soiling. The hot steam allowed the pressure to be minimised while still removing the soiling successfully, thus, the limestone surface was not exposed to any undue pressure. Areas containing a black pollution layer (that has formed on the sculpture over the past four decades) were treated with a conservation laser system. A wavelength of 1064 nm was used to remove the black layer. Fence panels covered with blocking sheets were installed around full parameter of the sculpture prior to using the laser system and a protective clothing including goggles for 1064 nm wavelength were worn during the treatment.
Aston University, Birmingham