Process instrumentation & controls provides a metal etching ink [instamark ink]. This type of etching ink generally works on metal etching principle and marks permanent acid, alkali, heat and solvent resistant marks on steel, brass, copper, zinc, tin and their alloys. In daily use, a number of components are required to be marked in inspection stages, at different machining stages, laboratories, stores, materials or for permanent stamping on finished products, etc. Normally marking done by marker and ink or paint peels off with time or disappears by solvents, water or heat and creates confusion. Engraving/punching is cumbersome process and is ineffective on hardened steel/irons. This ink eliminates all these problems.