rubber insulation

Isaac Kremer/ November 23, 2025/ / 0 comments

An extruded or wrapped electric wire insulation composed of 20-40 percent rubber withf illers of chalk, lamp black, talc, white or red lead, or zinc oxide; the copper wire was tinned to protect it from the sulfur used in vulcanizing the rubber; used late 19th century to 1950s; types include Duprene, gutta percha, Kerite. See also insulated wire. (Bucher, 1996)