Undercoat models black (no I didn't take a photo!)
Apply a heavy drybrush over all metal areas with GW's Tin Bitz (or whatever it is called now). Don't worry if you get it over the non-metal areas, we will go back to them later.
After the Tin Bitz has dried, lightly drybrush a steel colour over the Tin Bitz (I used Vallejo Oily Steel). The key here is not to completely cover the Tin Bitz and to have bits showing through underneath. Again, neatness is not a worry at this stage.
The models now need to dry for at least 24 hours so we don't get any pigment bleed when we use some ink washes next, so more tomorrow...