Salt Spray Test

Salt Spray Testing Procedure

First, small panels are prepared with the coating to be tested. The edges and the backs of the panels are protected, typically with tape. Then the front of the panel is “scribed” with a sharp tool to produce a scratch through the coating to the metal substrate.

Then, it is placed inside the test cabinet. The cabinet contains racks to hold the panels in position as specified by ASTM B-117 – tilted back 15 to 30 degrees from the vertical.

After it is closed,  and a 5% salt solution is delivered at a constant rate and temperature into the cabinet through an atomizer. Salt fog is sprayed upwards so that droplets will descend and settle on the panels.

To the end, there will be periodic checks of the test panels, as well as monitoring of the salt spray cabinet to ensure that it functions properly in the test. During these brief evaluations of the panels, it is determined whether the test is progressing as expected or if the coating on the test panels is failing prematurely.

Salt Spray Test Acceptance Criteria

Salt fog is a very harsh environment that can be found outdoors in marine conditions and industrial environments such as salt mines. The results of the ASTM B117 test are useful for designers, specifiers, and end users when standardizing the suitability of coatings for use under such conditions.