Primer B, the cyanoacrylate component, is unique to the present work and differs markedly in composition from that of cyanoacrylate adhesives. Concentrated cyanoacrylate monomer, with or without additives, is unsuitable for Primer B because it tends to coat the silicone rubber with a relatively thick film of hard, inextensible, and even brittle polycyanoacrylate plastic as it polymerizes. That polycyanoacrylate layer tends to have a dense, glossy or semi-gloss surface to which adhesives and coatings do not adhere well. Moreover, the layer itself does not always bond well to the underlying silicone rubber.