Electromarking is recognized as the best way to permanently mark conductive metal surfaces. It produces a sharp, attractive and economical design or impression. It does not cause distortion, sharp indentation, stress, burrs or strain. The mark is permanent because metal is etched away from the surface through the design stencil.
Electromarking can produce an etch ranging from less than .0001" to as deep as 0.010", through the use of AC or DC current. AC current makes a shallow etch from .0001" to .0002" in depth, depending on the length of time the stencil and the solution are in contact with the metal. The resulting etch is dark or contrasts with the surrounding metal. The degree of darkness depends on many things; however, the base metal is the most important.
For example, some stainless steels give only a brown mark, whereas monel metal gives a jet black mark. With AC, metal is etched away during half of the cycle and an oxide is deposited in the etch during the other half of the cycle. This oxide deposit will withstand corrosive action, as has been demonstrated by its capability to stand up under extensive salt spray tests over long periods of time. DC current provides a deep etch from .0001" to.010" in depth. This leaves a clear or white etch on most metals. With DC, metal is etched away during the complete cycle. The deep etch cannot be removed without removing the base metal to the depth of the etch.