I’m getting ready to do some minor refinishing of my airplane and went to Aircraft Spruce to order some Zinc Chromate. They offer two colors—yellow and green. My mechanic uses the yellow but I’ve noticed that the interior of planes is usually green. This site explains why. “Zinc Chromate was used as an anti-corrosive barrier primer; it could be described as a sort of painted-on galvanizing. It has been developed by Ford Motor Company by the late 1920s, subsequently adopted in commercial aviation and later by the US Military.”
“Sometimes, Zinc Chromate was mixed with Lamp Black paste to give a bit more UV resistance (Zinc Chromate is very sensitive to photolitic reactions) and more durability in high wear areas.…Mixing with black gave greener tones, which, depending on the amount of black added could run from apple greens to medium olive greens.”
I don’t think it matters which color I use, but I ordered the green. This way it will match the inside of the plane if I decide to spray any inside.