chipped paint???

does anyone have any experience and tips for painting chipped painted wood?
like this:

When on actual wood it's rather easy, just a dry brush and you're rather good... on plastics, I find that an old brush with a sufficient layer of paint does the trick. (old enough to have the hairs point out in different directions.

I'm a scenic artist, so I have to ask if you are talking full scale or for miniatures?

Haha, yeah, do you want to paint a miniature to look like this, or do you want to paint that actual door anew? For the latter, sand it down, then paint it again

i want a miniature to look like that door
actually it's the stagecoach and i want to paint it blue

There's a technique requiring salt and hairspray, and it's called salt chipping.

That is a great graphic!

Oh how i wish to own a airbrush! Dont even have to be a great one, just one i can play with!
Very nice graphic Catachanfrog!

I have one, but have not used it yet. I plan on using it as the weather gets a little warmer. Unfortunately, I have to use it in my garage.

That's not mine, just found it on the net
As for painting with an airbrush, I once tried it with a normal brush and it worked. Word of caution: make sure that previous layer (basecoat-> hairspray-> "top paint") has dried before moving to another step.
There are many good tutorials, youtube is especially helpfull.