History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s4.14

v1.c13.s4.14

(iii) Bidri Work - This craft of producing utensils and decorative objects, jewel boxes etc. decorated with beautiful designs produced by inlaying Gold and Silver wires on the surface of the object has been a speciality of the ‘Bidar’ tribe of Hyderabad. In this process as described by Mahamud (1988) at first a zinc base casting of the object is made using lostwax or any other molding and metal casting technique. The composition of the special alloy consists of 16 parts of copper, 4 parts of lead, 2 parts of tin and 112 parts of zinc. The casting is cleaned and its surface is smoothened and polished and then its surface is bleached by dipping the object in a solution containing Sal Ammonia, Saltpeter, Common Salt, Blue Vitriol and Resin mixed in a definite proportion known to the craftsman. This treatment produced a metal ware with grey black finish.