ASTM G85 Annex A2 Standard Practice for Modified Salt Spray (Fog) Testing
ASTM G85 Annex A2 Cyclic Acidified salt Fog Testing. For this variety of the Salt Spray Fog Test the standard 5% sodium chloride solution is acidified to a ph of 2.8 to 3.0 by adding the proper amount of acetic acid. The temperature in the exposure zone is maintained at 49°C +1.1 or -1.7°C (120°F +2 or -3°F).
This test is usually run under what is referred to as 'wet bottom' conditions. This prevents the inside of the box from drying out. Dry conditions would decrease the corrosion rate.
However, for testing 2000 series aluminum alloys and some paint coatings a dry bottom test is preferred.
The test is run as a series of six hour cycles. These cycles consist of: 3?4 hr. spray, 2 hr. dry-air purge, followed by 3 and 1/4 hr. soak at relative high humidity. To obtain complete specifications go to ASTM International.