Yes your right about being made for the airbrush, forgot that you you use a brush . Further research found thisLee - Thanks, and it's actually finished.
John - These are just the ordinary Vallejo Model Colour metallics - the only new Vallejo metallics I'm aware of are for the airbrush. I found it hard to get my head around water-soluble metallic paint at first, but I really like these.
" Brush painting of the Metal Colors is possible. It is best to apply the colors over a primer and apply a second primer coat for full coverage. While these paints self-level to the surface really well the Metal Color range was designed for airbrush application so when using a brush to apply on an entire model the final outcome over large areas may result in some uneven properties in the form of brush marks. " So would be a no then !
With thanks to the Michigan Toy Soldier for the quote .