Thanks everyone for the tips.
they are very useful
I made some projects, one I used a brush the first time and the second and third time I sprayed lacker.
the I did the next project only with my airbrush.
I found it hard to reach every spot on the inside of the cutouts.
I can paint it well, but then the area around it will be sprayed to thick.
Tried four/five thin layers, but didn't hit everything
so I still suffer with finishing the small cut outs on fretwork.