Bronzing

BRONZING, the coating of various paper and metal products with bronze paint (of various colors and shades, depending on composition). The main components of bronze paint are copper (in some paints it contains up to 99%) and zinc (up to 17%); aluminum and tin may also be present; while impurities and contaminants include iron, lead, and arsenic. Bronze paints find their widest application in the printing industry (in lithography) and in a number of small-scale productions where metal and paper products are bronzed. Previously produced mainly by hand, this operation has in recent times been largely mechanized; B. by hand method (at least in Western Europe) is carried out only when paper products are too small. Part of the work is done by the wet method. Both in manual work and on machines, in the absence of proper exhaust ventilation, a considerable amount of dust is released into the air. Bronzing workers very often show disorders of the respiratory tract (rhinitis, pharyngitis, laryngitis-hoarseness, scratching in the throat) and the gastrointestinal tract (loss of appetite, bitter taste in the mouth, belching, vomiting, pain in the stomach area, constipation). Gastrointestinal disorders are probably explained by the partial dissolution of copper and zinc in gastric juice. Among general disorders, headaches, anemia, etc., were noted. Lead, sometimes present in the paint as a contaminant (0.1-0.2%), can cause poisoning. - Preventive measures: complete mechanization of the production process, isolation of machines, covering machines with hoods, covers, etc., providing proper exhaust ventilation with downward suction.