So the clients request was essentially to get the main block colours down so they can work on the detail. The airbrush makes this a relatively simple job although getting smooth even coverage over a large flat surface does take some time to learn.
So it was as close as I could get to Codex Grey for the main colour with Gun Metal Grey for the metallics. I used Vallejo Game Colour Cold Grey (very well thinned down) and Vallejo Air Colour Gun, highlighted with Vallejo Air Colour Steel. The Cold Grey was laid down from from an angle so as to leave some shadows in the recess, particularly around the statues and windows on the superstructure.
[slight aside]
I have had gone through a couple of pots of the VAC Gun and Steel since I bought my airbrush. I have to say that unlike the rest of the Vallejo Air Colour range. Their metallics are quite fussy about going through my Iwata HP-C. I have to thin them down considerably. Anyone else experience this?
[/slight aside]
So that was all the client needed. However.....
As usual I couldn't help myself and had to do just a little bit more. It seemed a shame to have such a nice huge bore gun sat there with no kind of weathering on it....so I have airbrushed a blended up layer of sepia wash (made using Les' from Awesome Paint Job's mix) and then an extreme airbrushed edge of some GW Leviathan (ironically enough) Purple wash. This gives that really nice scorched patina you get from repeated application of heat around a barrel. I finished off the very edge with Tamiya Weathering Master series compacts Soot, Gun Metal and Silver. These really are a superb series of products and I would strongly recommend you pick these up if you are into your weathering.
Now taking pictures of this beast was a little tricky. It was somewhat bigger than my light tent will allow for so these are just taken on the table. Hope you enjoy.