How Does Spray Painting Work?

The spray paint can was invented as early back as 1949 based on the technology of the aerosol can. The spray paint is popular because of the ease in applying it and the smoothness and even coating that it leaves on the surface it is applied. It can be designed as a gas compression system or liquefied gas compression system.

The mechanism the spray paint uses to operate is based on pressure difference. A propellant is usually mixed with the paint in the can under high pressure. This propellant can either be in the form of gas or liquefied gas although the way they work tends to be very similar.

Gas Compression System

The propellant used in this case is gas based. In the manufacturing, after the paint has been transferred to the can, the propellant is compressed into the can under high pressure. When the valve is opened, the pressurized gas expands and forces its way out along with the paint through the tube inside the can.

Liquefied Gas Compression System

The mechanism here is very similar to the gas compression system. The difference is in the propellant use. Instead of the gas, the propellant is in the liquid state. When the valve is opened, the pressure difference makes the liquefied gas boil causing it to change rapidly to gas which expands and then propels the product out of the can. Some designs are made with ball bearings which is important in order to achieve a thorough mixture when the can is shaken before the product is expelled.

The propellant is usually inflammable. It should therefore be used with care in well-ventilated areas and should be properly kept away from children.