GMNA GM4260P PDF

GENERAL. Three commonly used methods for measuring the thickness of electrodeposits and anodic coatings are described; and reference is made to six additional methods.  Unless otherwise indicated, any method may be used when GM 4260P is specified.  The choice of method depends upon the precision desired and the feasibility of application to production parts.

Where referee checking is required, the Microscopic Method for deposits above 0.1 mil, the Interferometry Method for deposits below 0.2 mil (except for ground surfaces), and the Mass-Area (or Chemical) Method (except for zinc base die castings) are normally preferred.  These, and the other methods listed, are considered to be sufficienly accurate for routine production testing when used according to the instructions referenced.

Some methods require calibration standards, which are availablecommericially or can be readily prepared.