So I'm thinking about getting into some DIY Cerakote work for a few easy single color projects to start with.
But then I really got a steampunk AR build that I want to make that would involve using Robin's Egg blue for a corrosion look.  

Anybody want to guess how they do this effect?  
Is it.....
Overspray and wipe away?
Fine pencil spraying?
Something else?

It looks like they may have applied it by hand.

My guess is a wash by hand with a brush. A wash is a very thinned paint. It's so thin, it runs like water and pools in recesses like in the photos.

The green looks like it is aplied with a short, stiff, dry brush and built up or wiped off to get the desired effect before curing. 

Thanks for all the replies.

I think the answers net out to be......lots of experience, experiments, tests, and redos.

I'm thinking the stiff brushes mentioned may be like stencil brushes?

Lastly I read that for multi colors that Cerakote recommends doing FLASH cures between colors before getting all colors applied and then doing a full 2hr cure.
My question is.... can there be hours/days between the colors or does the 3-colors essntially have to be applied in one marathon session?
http://cdn.dick-blick.com/items/051/67/05167-OAA3ww-l.jpg

I would do that with a bronze base coat, and a black top coat... then wipe the top coat off.  Blue highlights added after.