How Airbrush Works?

Airbrushes have revolutionized various fields, from fine art and illustration to automotive design and makeup application. By leveraging principles of fluid dynamics, airbrushes can atomize and spray media such as paint, ink, dye, and foundation with remarkable precision.

Understanding how airbrushes work not only enhances their effective use but also allows users to better understand their tools. This article delves into the working principles of airbrushes, particularly focusing on the double-action type.

Basic Theory Principle of Airbrush

The working principle of an airbrush can be explained using principles from fluid dynamics, specifically Bernoulli's principle and the Venturi effect:

Bernoulli's Principle

This principle states that in a fluid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. In the context of an airbrush:

● Air Flow: The airbrush is connected to an air compressor that generates a stream of high-pressure air.
● Nozzle and Needle: Inside the airbrush, there is a nozzle and a needle arrangement. When the trigger of the airbrush is pressed, the needle moves back, allowing pressurized air to flow through the nozzle.
● Atomization: As the high-speed air flows through the nozzle, its speed increases. According to Bernoulli's principle, this increase in air speed leads to a decrease in air pressure at the nozzle tip.

Venturi Effect

The Venturi effect describes how the velocity of a fluid increases as it passes through a constriction, causing a corresponding decrease in pressure. In the airbrush:

● Paint Flow: Simultaneously, paint or another liquid is drawn from a reservoir into the airbrush.
● Mixing Zone: As the high-velocity air exits the nozzle, it creates a low-pressure area around it due to the Venturi effect.
● Atomization Process: The low pressure created at the nozzle tip draws the liquid paint into the airflow. This causes the paint to break into tiny droplets, atomizing it into a fine mist.

The Working Principle of Airbrush Compressor

1. Air Intake

The compressor draws in air through an intake valve or filter. This air is typically ambient air from the surrounding environment.

2. Compression

The intake air is compressed using a piston or diaphragm mechanism within the compressor. As the piston moves up and down (in reciprocating compressors) or the diaphragm oscillates (in diaphragm compressors), the air is compressed into a smaller volume.

3. Pressure Build-Up

Compression increases the pressure of the air. The compressed air is stored in a tank (if it's a tank compressor) or sent directly to the airbrush (if it's a tankless compressor).

4. Regulation and Output

A pressure regulator controls the amount of air pressure delivered to the airbrush. The regulated air is sent through a hose to the airbrush, where it powers the atomization process.

How Exactly Do Airbrushes Work?

After explaining the working principle theory of airbrush, here we will combine the theory and the usage of dual-action airbrush to help you better understand how exactly does airbrush work.

1. Initial Air Flow

When the airbrush trigger is pressed down, air from the air valve is allowed to flow through the air channels within the airbrush. This air exits around the outside of the nozzle tip. At this stage, no paint is sprayed because the needle is still fully forward, seated against the inside of the nozzle, blocking the paint flow.

2. Trigger Mechanism and Paint Flow

As the trigger is pulled back, the needle retracts from the nozzle, creating a circular gap around the needle tip. This gap allows paint to flow from the reservoir into the airstream. The paint is then drawn into the airflow and atomized, thanks to the Venturi effect mentioned above.

3. Control and Precision

Double-action airbrushes provide superior control over both air and paint flow. Pressing down on the trigger controls the airflow, while pulling back on the trigger controls the paint flow. This dual control allows for precise adjustments, enabling the creation of fine lines or broader spray patterns as needed.