Chapter 3: Air Spray Method
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What is Air Spray Method?
Example of Workpiece
It is a spray that uses air to compress and control the paint spray pattern, which allows paint to atomize into the workpiece throughly. In most cases, spraying is usually a small workpiece, complex object, low viscosity paint and corner nook around surface.
This spray technology is the traditional spray paint. It's less complex technology when compare with airless spray, air assist airless spray but offers the best spray performance in terms of resolution and atomizing control. Therefore, it is applicable to use for completion job, re-painting after main spray.
Although this method may waste time and waste a lot of material paint when compare with another spray type, the advantage is spray quality. User who use air-spray method will focus on the quality of work as the primary purpose rather than cost-savingng and time-saving. However, if they concern time and cost-saving as priority matter but need to use air spray method, there also have electrostatic technology for spray guns to solve this problem. For example, WAGNER GM5000EA.
However, this website emphasize air spray gun for small production scale, completion work, decorative finishing and special purpose work. For example, automotive finishing in garage.
Fine Spray
It is a compressed air-driven spraying method. At the outlet of the nozzle, the material is mixed with a air at the nozzle which consist of pattern air flow and atomization air flow. After that, material paint will be spray and control by air pressure which produce an extremely good spray pattern. Although this method provide the best spray pattern, it has a lot of chance to create overspray because it require paint quantity and air pressure so it might atomize a lot of paint. We recommend work in spraying booth.
Example of Fine Spray
Relationship between Material Paint and Air Flow
High Volume and Low Pressure (HVLP)
This is another type of air spray method to solve overspray problem from ordinary spray. It focus about deliver paint to surface object in high volume but use less air pressure. Using ordinary pressure might make overspray that it can't provide good surface quality. Therefore, HVLP decrease air pressure and increase paint volume to reduce the spray mist and give larger material droplets
HVLP Spray gun in industrial coating.
HVLP spray gun in architectural coating.
Example of Spray Pattern for Air Spray
Air spray provide spray pattern with tulip mark. Usually, it can be adjust to spray in vertical pattern or horizontal pattern which depend on job requirement whether fine spray or HVLP.
Spray Pattern from Air Spray Gun
Type of Air Spray Gun
Air Spray - Gravity Type
Material container are installed directly above spray gun. Fluid will be flowed to nozzle by gravity force. The connector gate between container and gun are open automatically by trigger. If trigger is activated, material will be flowed and mix with air flow then spray out automatically. This are spray gun type is applicable to use with a few material paint quantity but it is high solid material. For example, using with metallic paint. Especially, most of spray gun which use auto-body shop are gravity type.
Air Spray - Suction Type
Material container are installed directly below spray gun. Fluid will be sucked up to nozzle by suction tube. The connector gate between container and gun are open automatically by trigger. If trigger is activated, material will be suck up and mix with air flow then spray out automatically. This air spray gun type is applicable to use with a few material paint quantity and low solid.
Air Spray - Pressure Type
This type must use with feeding pump or pressure tank because the material is high viscosity than gravity type and use a huge material quantity more than gravity type and suction type. So it is regular for mass production type.
Feeding pump and pressure tank must be designed to use with Air Spray method only.
Example of Feeding unit by pump type and pressure tank type
Feeding unit
There have 2 common types of feeding units. 1st type is feeding pump that material container are separated each other and feed to spray gun by using suction tube suck material from container and deliver to spray gun. The advantage is simply changing color. 2nd type is pressure tank that container unit and feeding unit are installed in the same unit. There have agitator which installed within tank. No need to stir material paint like feeding pump. It can be use material quantity more than feeding pump but it is suitable to use only 1 color for long working period.