The cheapest rust effect technique

After the previous weathering technique, I would like to show you a technique that many of you may know, but for those of you who don't, you can try it now.

All you need is the desired rust colour, water, salt and an airbrush or spray paint.

1. Paint rust colours on the surface.
2. Dampen the areas where you want the rust effect with water.
3. Before it dries, sprinkle salt on it.
4. After drying, spray with airbrush or spray paint.
5. After drying, use a toothbrush or something dry and soft to remove the salt from the surface.

A picture of this is attached, but you can also watch the process in the video.

1 additional image. Click to enlarge.