ASTM A239-14

1.1 This practice covers the procedure for locating, by the use of a solution of copper sulfate, the thinnest spot in a zinc coating (hot dipped, electroplated, or sprayed) on iron or steel articles that are coated after the shape is produced by casting, drawing, pressing, or other forming methods. Examples are: electrical metallic tubing and rigid conduit pipe, castings and forgings, and structural steel; on special hardware, such as poleline, builder's, and farm implement hardware; bolts, nuts, screws, and other miscellaneous general hardware.