In an earlier post I had posted an article about painting yellow and using the Forgeworld pigments to create rust (or other weathering textures) using diluted pigment powder. I first blended the armor plates with highlights and shadows, then powdered up the edges were rust and grit would settle. Then I would wash over the model with water which would dilute the powder and let it run into the cracks.
Well, with my second attempt I decided to try something completely different. First off, I can not take credit for this method as I watched a tutorial on how to do it. And the person that presented the tutorial is none other than....Slayer Sword winner Todd Swanson. The tutorial went over the exact steps and methods that were used to achieve the dirty, battle torn, rusty armor plates that he used on 'Festus'. After watching his tutorial vid, I was so pumped up to give it a try. So I picked up the nearest model I had, which happened to be a Imperial Fist Dreadnought that was a WIP and threw some paint on it.
Though this is only my first take at it, I'm sure that I can dilute the paints a bit more and create a much better transition between the drips of rust. I was kind of anxious to see the outcome and painted a bit thicker than I wanted.
From about half-arms length away: