FromTheWarp archives from the talented Ron (hope he is enjoying his hiatus away from blogging) I found a simple tutorial of how to achieve this effect using simple washes.
I used Nuln Oil, Asurman Blue, Leviathan Purple and Seraphim Sepia one after the other, blending somewhat the edges between colours to achieve the pictured nozzles. Not bad at all.
The Xiphon Pattern Interceptor is now built, wings, engines and nose all pinned for strength and primed.
Great little technique I thought, cheers Ron.