First, a mould is formed from soil made malleable by the addition of castor oil and resin. The molten metal is then poured into it to obtain a cast piece which is later smoothened by filing. The casting is now coated with a strong solution of copper sulphate to obtain a temporary black coating over which designs are etched freehand with the help of a metal stylus. This is then secured in a vise and the craftsman uses small chisels to engrave the design over the freehand etching. Fine wire or flattened strips of pure silver are then carefully hammered into these grooves. The article then is filed, buffed and smoothed to get rid of the temporary black coating. This results in rendering the silver inlay hardly distinguishable from the gleaming metallic surface which is now all silvery white. The bidriware is now ready for the final blackening process. Here, a special variety of soil which is available only in the unlit portions of the Bidar fort is used.[2] It is mixed with ammonium chloride and water to produce a paste which is then rubbed onto a heated bidri surface. The paste selectively darkens the body while it has no effect on the silver inlay. The paste is then rinsed off to reveal a shiny silver design resplendent against the black surface. As a finishing touch, oil is applied to the finished product to deepen the matt coating. The finished product appears black with brilliant silver inlay. Bidri artisans tell that identifying good quality of soil from the fort is done by tasting it with the tip of the tongue and this knack is passed on from generation to generation.
