I'm curious as to your weathering ideas for bridge decking. Creosoted timbers are actually not black, but a very deep brown. But molded plastic comes in glossy black. What do you folks do to give a mild to moderate appearance of sun and weather washing away some of that newness? I don't want it to look like it has been there for one hundred years of abuse and neglect, or was abandoned. But wish it to seem used, yet decently maintained. Dry brushed? Using what colors?
Wood tends to grey, sorry gray, with age. I'd knock the shine off plastic ties first, then brown them with a realistic colour, I like Humbrol natural wood. seal with acrylic varnish, then use a wash of leather dye (black/brown mix) and IPA mix, 20:1 ratio to sit in the molded grain to add depth. A little dry brushing of varying shades of grey to make it "pop".