The air cap and head assembly are on the front of your airbrush and they cover the tip of the needle. The purpose of these parts is to control atomization of the paint spray. Should these parts become dented or damaged in anyway you should replace them immediately. Damage to the air cap and head assembly will effect the performance of your airbrush. Professional Airbrush Techniques by Vince Goodeve will teach you some pretty intricate designs. This book will help you learn how to prepare metal surfaces so that you can begin to learn or advance with airbrush art on motorcycles and cars. While the book will teach you some intricate designs do not worry though cause the book, also has some simple projects that you can start with when working with airbrushing motorcycles and cars. Advanced Airbrush Art DVDs Once you have learned the basics with airbrush art, you can start to learn more advanced techniques. These advanced techniques will help you to render more imaginative art. Videos can help you learn this advanced airbrush art techniques. You can also get videos that will help you learn how to render a specific design that will fit with the airbrush art you are trying to create. This is a good one if you are just wanting to gain more knowledge on airbrushing techniques whether you airbrush as a hobby or you do it professionally. The wide array of surfaces that Airbrush Technique Magazine covers includes but not limited to t-shirts ,canvas, the body, autos, motorcycles and so much more. There are couple of ways that an artist can learn how to do micro airbrush art. One way that an artist can learn how to do micro airbrush art is to obtain a video created just to teach micro airbrushing. AirBrush Action has a video titled Micro Airbrushing that features airbrush artist Robert Benedict. Make sure that all the leather has been wiped down and that the alcohol has dried before beginning. When you begin you need to place a base coat of Opaque White first before you begin your actual airbrush design. Wood surfaces should be sanded prior to doing any airbrush art. Take the time to use sand paper and lightly sand the wood down by hand.