To determine the adherence of the zinc coating to the surface of the base metal, use the point of a stout knife. Cut or prise, with the application of considerable pressure, in a manner tending to remove a portion of the coating.
The adherence shall be considered inadequate if the coating flakes off in the form of a layer or skin so as to expose the base metal in advance of the knife point.
Testing shall not be done at edges or corners (points of lowest coating adherence) to determine adherence of coating.
Likewise, the removal of small particles of the coating by paring or whittling shall not constitute failure and therefore not be grou nds for rejection.