While reading another post a few minutes ago, I was reminded of a texture tutorial I made on some forum once. Thought i'd repost it.
This is for a cast metal effect, or rust.
First you take some Mr Surfacer 500
And an old brush. This one is kind of small for 1/16 scale...
Brush on the Mr Surfacer
While it's still wet smash the brush up and down (the reason for the 'old' brush). Because it's lacquer based, it dries fast, but sticky, so when you smash the brush, it sort of lifts the paint as it's drying, which gives you the texture.
And here's the difference. The more you smash, the thicker the texture. You can also sand it smoother if you've done too much.
The painted piece. I painted half red because I showed it on a car modeling site for cast engine parts (ferrari testarossa cast valve covers for example) the other side shows rust color.
So there you have it.. I hope someone can put that to use.