Most compressors will give you at least 125 psi, so the most important factor in selecting the right gun for you is to select a gun that matches your compressor’s CFM (cubic foot per minute). This needs to be the free air driven (FAD) figure, not the displacement figure used to sell the compressor, which will be some 30% higher. For example, a compressor with a 14 CFM displacement figure will give you around 10 CFM free air driven (FAD).
Low Volume Low Pressure spray guns, these work well with low CFM compressors e.g. 6-9 CFM at low psi. LVLP spray guns can operate at less than 10psi at the aircap, whereas a HVLP gun will operate at a minimum 10psi at the aircap and is usually pushed higher to acheive better atomization. LVLP has a higher transfer effiency when compared to a HVLP gun, meaning that around 70-80% of the product being applied and sprayed correctly will land on the surface being painted.
Rusty says “Spraying with an LVLP gun is a great option if you want to have low air consumption and are using a lower strength air compressor, save some money and jump into the world of DIY painting, or even semi-professional paint jobs quickly and cheaply”.
High Volume Low Pressure spray guns generally require more air volume CFM but at low pressure.
Rusty says “While conventional spray guns use high-pressure air to finely atomize fluids, HVLP guns spray fluids softly with air pressure reduced to around 0.05 to 0.1 MPa (7–14 psi). The downside to these guns is that you’ll need a larger compresspr as to compensate for lower air pressure and maintain atomizing performance, they use larger amounts of air instead.
Use a reasonably high volume of air and often a much higher air pressure. Great for atomising paint.
Rusty says ” of the three listed above it not my favourite due to the amount of overspray produced, Great for atomising coatings and cheap to purchase”.
Use hydraulic pressure from a pump to compress the paint and spray through a single spray tip with no added air to atomise. Excellent for spraying high build coatings unthinned.
Rusty says ” typically used in the UK by painters and decorators on sites around the country, here at Rustbuster all our underbody wax is applied by Airless, Fantatsic finish, speed of application and simple to use”.
DIY electric spray guns
Will spray low viscosity materials adequately but are unable to atomise high build coatings sufficiently.
Rusty says ” They have there place around the home and in the garden but have limitations, material needs to be thin to go though the machine.