Late last year I cut out a small section of my already-damaged original air cleaner in order to try to identify a good match for the original blue/green paint color to repaint the 320’s air cleaner. Earlier this month I was finally able to get that sample matched and have some paint made up.
I went to Ace Hardware, where they sell oil-based Rust Paint and offer a color-matching service using their computer. I had to flatten my slightly-curved metal swatch, but they were able to get a good reading and mixed up a gallon of paint for me.
Here is the tag that identifies the color recipe for posterity, and a shot of the open can of paint.
I tested the paint on the lid of my air cleaner. Using a foam brush I painted half of the inside of the lid to get a sense of how close the paint was.
I think it is a pretty good match.