This is a recipe that shows how to paint the blue-grey colour that I use for my 40K Imperial Navy fliers, be it bombers, fighters, transports etc. It uses the following paints: Black Primer (AK Interactive) Mechanicus Standard Grey (Citadel) Dawnstone (Citadel) Fenrisian Grey (Citadel) Drucchi Violet (Citadel)

This is a common approach I take for metals on larger scale minis, where I have room to transition to lighter shades of metal before edge highlighting. It uses the following paints: Aqueous Steel (Mr. Hobby) Iron Warriors (Citadel) Leadbelcher (Citadel) Stormhost Silver (Citadel) Drucchi Violet (Citadel)