Mr. Ken, when I wrote "true French gray" thats what I meant-that is how I have seen it done, in France. By playing with the concentration of the final quench chemistry, they are able to predictably tone the final color, from almost a green gold out to what would pass for silver plating, or anything in between, say, a matte pewter. There is no elbow grease involved in the final tone, or color.
When I say " fairly delicate" in terms of rust resistance, I am comparing it to a mil spec type 120 degree salt water spray test @ 48 hours. Epoxy and Robar finishes demonstrate superior performance to traditional, blue and hardened surface treatments in a "real", repeatable test.
Best,
Ted
