There are many ways to paint different effects on line which really are amazing. I would like to show you a very easy way to paint rust that is quick and offers a very realistic look. It looks great everywhere from rusted vehicle parts to tank exhausts to any weathered metal buildings. This involves only three paints: a dark chocolate brown, a red brown and orange.
First, dry brush a large area with a flat brush where you want the rust to show. Make sure this area is much larger than the final area in which you want the rust to be present. As a tip – drybrush all the dark brown spots at one time before progressing to the red brown paint.
With the same flat brush, lightly dry brush the red brown to an area inside the base dark brown. This area does not have to cover the entire dark brown area and may have 2-3 areas of red brown for effect.
Finally, take a very small amount of orange and dry brush a highlight in the very center of the red brown areas. Apply the orange in different strengths to get a more varied effect in different areas of the red brown, taking care not to paint outside of the red brown area.
That is it, really! For my project, I placed a very light dry brush of steel over the rusted area to show that the rust was in the recesses of the corrugated metal roof. Feel free to experiment on your vehicles and structures and have fun!