Single action is when the trigger is depressed, and paint flow regulated separately out of the airbrush. Dual action means first the trigger is depressed and air flows through the airbrush. Then as you pull back on the trigger, material will flow through the tip of the airbrush thus giving you much more control at your fingertip.

You can spray a variety of paints and media as long as it can be reduced similar to the consistency of milk. Some paints may be very toxic to spray and would require proper respirators and a spray booth system. Always wear a respirator or particle mask when airbrushing. Beginner airbrush artists may consider purchasing ready-to-spray airbrush paints or pre-reduced paints as reducing paints to the right consistency can be challenging.

There a few reasons for this. The fluid nozzle and or air cap may be loose, causing it to bubble. The fluid nozzle may also be dirty and clogged with dried paint particles. Lastly, there may be a crack in the fluid nozzle which you will need to replace. Also make sure to thoroughly clean the needle. Any dried paint on there will assist in not spraying.

Using multiple airbrushes simultaneously will require a compressor with enough C.F.M. (cubic feet per minute) rating. High powered Dual head compressors are a good choice to hook up two airbrushes simply because of the higher air output. Manifolds are used to hooking up more than one airbrush hoses

Having a tank on the compressor helps regulate a steady and consistent airflow as the airbrush is drawing air from the tank whereas a tankless compressor feeds the airbrush directly

One version is not necessarily better than the other as different jobs require different tools.  Siphon feed airbrushes are great for spraying larger background areas for t-shirts, tanning etc. Great for production. Gravity feed airbrushes are great for all around airbrushing and especially for high detail artwork.  Great for studio work.

Airbrushing fingernails is delicate work requiring small amounts of paint at a time. You will want a gravity-fed dual-action airbrush with a small reservoir for the paint (1/32 oz instead of the larger 1/3 oz. cup with most other gravity-fed airbrushes). Airbrushes with the 1/32 oz reservoir can easily operate with a few drops of paint.

If you are using water-based paints, you can simply use water, an airbrush cleaning brush and airbrush cleaner. Some manufacturers have their own airbrush cleaning solutions for this. Poor some of the appropriate cleaner in the airbrush spray onto a paper towel until it sprays clear. Plug up the tip of the airbrush and pull the trigger back making it "bubble." This is called back flushing. Flush and back flush several times, rinsing frequently. Remove the needle and wipe clean. For solvent based paints, use the appropriate reducer or solvent."

It is NOT recommended to run clear coat through your airbrush. You will want to use at least a mini spray gun for clear coating. For large jobs requiring large amounts of material, use a full-size spray gun in a spray booth atmosphere. Always wear a mask when spraying.

Make-up artists like to use a gravity-fed dual-action airbrush with a 1/16-ounce medium sized cup on top. With make-up, you are not using a lot of material, so a medium cup is preferred over the larger 1/3-ounce cup.

Airbrush tanning is usually done with a single-action siphon-fed airbrush with a 3-ounce jar.