3004 aluminum alloy in the H291 temper.
Exterior of vehicle driven on the prairies.
Since Testlabs International had analyzed coating failures of the one-coat system used in the past, the company implemented a two-coat paint system for the aluminum sheets.
Ranged from five to eight months.
The two-coat paint system, which specifies a total dry film thickness of 1.1- 1.3 mils, has reduced the number of corrosion sites as compared to the one-coat paint system.
With the one-coat paint system, there were 100+ corrosion sites / ft2
With the two-coat paint system, there are five to 17 corrosion sites/ ft2