The Gustav was built straight Out of the Box although, like the AFS Mk II before it, I may add a sci fi looking antenna later on the right side antennae mount.  The model is painted in Model Master Aluminum for a base coat, MM Enamel Dunkelgelb, Tamiya Dark Brown (50/50 Flat Brown/Flat Black), and oils for the pilot bust.  Weathering was done with table salt for simulating chipped paint and a whitewash of white pastel/water mix.  Rust on the plumbing is pastel dust.  Decals were applied over flat paint with Future.  A detailed build-up can be followed here at Starship Modeler.

Done...............................................................................With the AFS Mk II

Backside with rusty pipes

Painted.......................................................................................Decaled

Whitewashed