So make sure the paint you are using is safe for the surface you will be putting your airbrush art onto. Water soluble acrylic paints are used for airbrushing art onto plastic, metal, vinyl, wood, ceramics and cloth. This makes this type of paint the choice for airbrushing art onto your model cars or airplanes. This rough grainy effect will help the paint to adhere to the metal. With metal actually being smooth the paint will have a hard time sticking to the smooth surface. This is why it is important to wet sand the metal first. A base coat should be applied to the metal before any airbrush art design is started. With needles most artist find that the airbrushes coming out of China bend easier than any of the other airbrushes. So look for one that is made elsewhere so that you do not have to keep trying to straighten a bend airbrush. The best airbrushes to use that are the easiest to take care of are name brand airbrushes. This will create a atomized fine dot spray pattern. This makes the internal mix a good choice for fine detailed work in your airbrush art. The point at which they come together is in the head assembly. The external mix is where the air and paint come together outside of the head assembly or the fluid assembly. So when interested in learning about how to apply airbrush makeup then look into the websites for artist that practice this form of airbrush art. Usually they will have a place on their website that talks about offered workshops. One such airbrush artist is Suzanne Patterson of Creative artistry. Suzanne Patterson has held several workshops teaching people hands on all about the art of applying airbrush makeup. All you need to know how to do is successfully use the stencil that you wish to use for your design. The main key is learning how to control the airbrush gun so that you can get the paint only where you want it and not overcast the paint where you do not want it. Once you master that then your options are endless with the vast array of stencils out there.