I'm painting my helmet and jetpack with thinned humbrol in airbrush. The problem is that it runs! In my last try, I used a lot less thinner, about 4 parts paint to 1 part thinner, and it's still just a lot of mess. I don't use thick coats, so I don't know what I can do different.
Any suggestions, please? I'm meeting Jeremy Bulloch in two weeks and want to be in armour!