And then there is price. The more you spend, the better the machining and interchangeability in the fluid-nozzle components and the better the atomization and flow. There are good all-around guns that have a single tip in the 1.7-1.8mm range that can be used to spray primer and a single or dual-stage paint job if cleaned and cared for. There are also kits that include two guns as a set with an extra nozzle to cover larger jobs and heavier paints with a smaller detail gun to hit under the hood, the wheels, and the doorjams. Detail work, custom paints, and a shop that uses high volumes of paints are going to require an expensive gun in the $500-$600 range. These guns are designed to use higher head pressures for better atomization and particle distribution while still keeping the TE up. Regardless, when we spoke to local painters, they were still impressed by the abilities of the $100 guns. The best way to decide is to ask the person who sold you the paint or a few reputable painters for their recommendations.
The Car Craft compressor is massive enough to handle the paint guns in this story so we dialed in the proper pressure. A good rule of thumb is inlet pressures of no more than 35 psi for lacquer and 43 psi for enamel. | 
Ouch! The paint takes a bite out of the budget. The pint of Chroma One Acrylic Urethane, the activator, and the solvent hit us for another $99. Don't forget the mixing cup and stir sticks. |
You can adjust the spray down to a circle for small areas or a wide fan for large ones. The most important aspect is to overlap the lines about 50 percent and keep moving. | |
Air Compressors
For once, more horsepower isn't always better. In the case of air compressors and paint guns, you need volume and pressure instead. Paint guns are rated by the number of cfm delivered at a certain psi. For example, our Craftsman gun has an air-compressor requirement of 8.6 standard cubic feet per minute (scfm) at 40 psi. That means the compressor you pick must be able to produce that volume at that pressure consistently while you are using the gun. The rule of thumb we've repeatedly encountered is the compressor must produce 1.5 times the cfm that the gun requires at a given pressure (in this case, 12.9 scfm at 40 psi). Craftsman recommended its 7hp 60-gallon compressor that can deliver at least 12.4 scfm at 40 psi and 10.2 scfm at 90 psi with a maximum pressure of 150 psi. A compressor like this will cost around $500. The average $299 compressor is going to have trouble keeping up, forcing you to wait for the pressure to come back while parts of the paint dry. Not good.
Another hidden cost is the filter and regulator. Both are needed to keep debris out of the paint, and since our compressor can deliver over 100 psi of unregulated air, the regulator is mandatory to keep the inlet pressure below the required psi. Ask the paint-gun manufacturer about the recommended compressors, filters, and regulators required to run the gun before you buy it.