Tin Coating Test

The continuity of the tin layer on steel wire can be tested by placing the wire, after a thorough cleaning, in a solution at 30°C (86°F) made up of gelatine, potassium ferricyanide, ordinary salt and distilled water, for a period of 1 to 3 hours, when porous areas appear as blue spots. The average weight of tin coating on steel wire is determined by dissolving it in hydro­chloric acid with antimony-trioxide, and finding the difference in weight of the sample before and after treatment.