There are many models of airbrushes available for consideration and some are better suited for spraying acrylics than others. If possible prior to purchase, visit an airbrush supplier to see what is available; to ask questions, and to hold the airbrushes in your hand to make sure it is comfortable and has good balance. If you have the opportunity, test spray various airbrushes.

Most airbrush users today use double action, internal mix airbrushes because they offer the most control and have the finest sprays. Single action, external mix airbrushes produce a coarse spray pattern, and depressing the trigger delivers a preset amount of paint. The amount is regulated by turning the needle adjustment screw at the rear of the handle, or by turning the paint volume adjustment knob at the airbrush front in the case of an external mix brush.

Double action airbrushes operate by depressing the trigger completely to release air and pull back on trigger (while depressed) to release paint. Amount of paint applied is determined by how far back you pull the trigger. This gives you the ability to paint non stop and increase or decrease paint flow simply by how much you pull the trigger back or push it forward, providing much more control than the single action airbrush.

Internal mix is a type of airbrush where the paint is atomized inside the airbrush tip. Airbrushes with a needle running through the airbrush are internal mix, and are the most common. The external mix airbrush atomizes paint outside the airbrush tip.

There are three ways paint can be delivered into the airbrush. Gravity feed airbrushes have a top mounted paint cup from which paint is drawn into the airbrush. Bottom feed airbrushes siphon paint from a jar mounted under the airbrush and enables the user to change colours quickly. Side feed airbrushes siphon paint from a small cup mounted on the side of the airbrush.

I own all three of these airbrushes, and prefer the side feed type. You can add just a few drops of paint if you wish; there are various size cups available; easy to clean and change colours; can rotate cup; good vision of area to be painted as there is no cup on top; usually can mount cup on either side of airbrush; and better balance in hand compared to airbrush with large cup on top.

Airbrush nozzle size is another consideration. Iwata and HobbiPen gives the actual measurement of the needle, ie: 0.3 mm, while Paasche and Badger describe needle sizes as fine, medium and heavy. The fine is for light fluids; the medium for medium fluids, and the heavy needle is for heavy fluids. The medium needle works quite well with acrylics and will serve you well. With the fine needle, your acrylics will have to be thinned further. A larger nozzle and diameter of needle will allow a larger volume of paint to exit the airbrush, while a smaller nozzle is designed for less paint volume and finer detail painting.