Definition - What does Edge Retention mean?
Edge retention in a coating process is a technique that ensure that the edges of a material that is being protected from corrosion or rusting by a protective coating material is applied on the edges in a sufficient amount. It can also be defined as the percent of coating after application that remains on an edge compared to that remaining on an adjacent flat area.
Corrosionpedia explains Edge Retention
In order to avoid an insufficient coating film thickness on certain areas such as corners, edges and weld seams in industrial structures (e.g., the ballast tanks of ships), mechanical grinding of the edges is required so that once the coating is applied it is retained there for a longer period and has a smooth edge profile. A smooth edge profile helps to retain liquid paints and coatings for a longer period compared to sharp edges. In order to retain the coatings on the edges for a longer period of time, it is important to perform “3 Pass or 2 R” edge grinding processes prior to surface preparation before application of a paint or coating.