Types of Common Air Spray Guns

Air spray guns come in many types due to their different functions. Since classification is based on different criteria, the methods of classification are also varied, often divided according to the purposes of car paint repair. Based on the different methods of paint supply, spray guns can be divided into three types: siphon, gravity-feed, and pressure-feed. Siphon and gravity-feed are commonly used for repair painting, and are often referred to as bottom cup guns and top cup guns based on the position of the paint cup installation.

Siphon Spray Gun

In a siphon spray gun, the compressed air flow generates a low-pressure area at the air cap, providing a siphon effect. The siphon spray gun is the most commonly used type of spray gun. The paint is placed in the cup, and when the trigger is pulled, compressed air rushes into the spray gun. A local vacuum is formed as the airflow passes through the air cap openings, which causes the paint in the cup to flow towards the opened needle valve, forming a mist spray. The air pressure of the spray gun is around  0.30MPa. The vent hole on the paint cup cover must be opened. The capacity of this spray gun's paint cup is generally 1L or lower, and it is currently only suitable for low to medium viscosity paints.

The siphon spray gun is suitable for occasions where colors change frequently and paint consumption is low.

Gravity Spray Gun

The paint cup of a gravity spray gun is located above the spray gun. It uses both the suction force of the air flow and the gravity of the paint to let the paint flow into the spray gun. This paint cup does not need a liquid suction tube, because the paint outlet is located at the bottom of the paint cup. The vent hole at the top of the paint cup must be opened. Considering its weight and balance, the capacity of the paint cup is generally limited to 600mL . The air pressure of traditional gravity spray guns is around 0.30MPa . New eco-friendly spray guns have an air pressure of 0.15MPa.

The gravity spray gun is suitable for small-scale operations, such as local repairs. This type of spray gun can be used in situations that require less material than a siphon spray gun, but where the paint viscosity can be a bit higher.

Pressure-Feed Paint Gun

In a pressure-feed paint gun, the paint is pressurized in a separate paint cup, tank, or pump. Under pressure, the paint is atomized at the air cap as it flows through the nozzle. The air pressure of the spray gun is around  0.30MPa.

A pressure-feed paint gun is often used when the paint is too heavy to be siphoned or when spraying operations need to be completed quickly. This type of spray gun is suitable for large-scale operations, and the painting workshops in general car manufacturing plants usually adopt this spray system.