Choosing the Right Paint Gun

SAMES KREMLIN automatic spray gun

Paint guns can be either manual or automatic.

Manual paint guns

Manual paint guns are used by an operator, generally in workshops and in the construction industry, to paint small batches of parts.

These are most often low-pressure guns (around 6 bar). They are often made of aluminum to reduce their weight, making them easier to handle and less tiring for the operator to use.

Automatic paint guns

Automatic paint guns are designed to be integrated into automated paint stations on mass production lines.

They are powered by compressed air and can be used to paint parts of all sizes.

PREVOST spray gun

There are several types of spraying systems available, and it’s important to determine which one suits your needs before choosing a model.

Low-pressure electric guns

These guns have a small compressor and therefore only need an electrical power supply to operate. 

They are mainly intended for occasional work on small surfaces.

Advantages:

• Lightweight and easy to handle, they are popular with DIY enthusiasts.
• Although very basic, they are very efficient and inexpensive.
• They do not require an external compressor to operate.

Disadvantages:

• They are only suitable for small surfaces.
• Heavy body paints (acrylic, glycerol) need to be diluted with water or white spirit.

Pneumatic or air guns

These use compressed air to spray paint and must be connected to an external compressor or compressed air network. 

In terms of how the gun receives the paint, there are a few different options. In gravity fed and conventional suction fed paint guns, paint is transferred from a cup attached to the gun to the nozzle. Pressure fed guns receive the paint via a hose connected to a pump or pressurized tank.

Advantages:

• Inexpensive technology that has been tried and tested

Disadvantages:

• High fogging or misting effect (overspray created during application and deposited on unprotected surfaces)

HVLP and LVLP guns

HVLP guns

HVLP (high volume low pressure) guns spray paint at low pressures (around 0.7 bar) using a high volume of air (8.5-40 m3/h). Spraying is smoother with this type of gun than with conventional paint guns, resulting in less overspray, better adhesion of the paint to the surface, and less product waste.

HVLP guns are designed for small-scale work.

Advantages:

• They are very efficient.
• They provide a better finish than high-pressure guns.
• They produce little misting or overspray.
• They reduce paint waste and therefore save money.
• Since they produce less mist, they reduce pollution, make site clean-up faster, and limit toxic waste disposal costs.

Disadvantages:

• They are mainly suitable for small surfaces.

LVLP guns

LVLP (low volume low pressure) guns use less air volume and lower pressure than HVLP guns. They spray paint at low pressures but are not limited to 0.7 bar like HVLP guns.

Advantages:

• They provide better atomization than HVLP guns for products that are difficult to coat.
• They are suitable for water-based products.
• They spray faster.
• They provide a better finish.
• They use less air.
• They are more suitable for large surfaces.

Airless guns

These guns do not use compressed air at all. Spraying is achieved with an external high-pressure pump that forces the paint to pass at very high pressures (up to 300 bar) directly through a small orifice in the spray nozzle.

The pumps can be fed from a reservoir or draw the paint directly from a paint can.

Advantages:

• They are cost-effective.
• They are easy to handle and offer comfortable working conditions.
• They can be used to spray a variety of products (paint, varnish, acrylic, dispersion paint, latex, etc.).
• They are suitable for large paint jobs (buildings, naval equipment).
• They allow you to apply a lot of paint in a short time.

Aircoat or air-assisted guns

These are specially designed for spraying solvent-based products such as varnish. They combine the airless spraying method with medium pressure. They use a small amount of compressed air to spray, reducing paint waste.

Advantages:

• They reduce paint and air consumption.
• They provide better quality finishes.
• They can be used to spray small areas.

DEVILBISS paint gun

There are three ways of feeding paint to pneumatic paint guns, and therefore three gun configurations.

Pressure fed  

With pressure fed guns, the paint is fed under pressure through a hose before being sprayed. Pressure fed guns have one connection for compressed air and a second for the paint hose.

Advantages:

• They can paint in any direction.
• They are suitable for large paint volumes.

Disadvantages:

• They require an external pressurized paint supply.

Sucion fed 

With suction fed guns, the paint is held in a reservoir (cup) located beneath the gun and is sucked up to the gun’s tip before being sprayed. This type of gun has been used for many years in the automotive industry.

Disadvantages:

• The compressed air pressure must be high in order to suck the paint out of its reservoir. Therefore, this configuration is not available for low-pressure systems, which offer a better finish.
• Since these guns require more air pressure than a gravity fed gun, they are not energy-efficient.

Gravity fed

The paint is stored in a reservoir (cup) located above the gun. The paint in the cup descends with the pull of gravity. This system ensures that the gun can use all the paint in the reservoir. The disadvantage of this type of feeding system is that it only works if the gun is oriented so that the paint flows correctly. It is therefore not possible to paint in all directions.

Advantages:

• These guns are ideal for small jobs and precision work.

Disadvantages:

• They do not work with viscous and heavy body products unless they are diluted.
• They are not suitable for large-scale jobs.
• It is not possible to paint in certain directions (upwards, etc.).

GRACO paint gun

There are several factors to consider when choosing a paint gun.

Type of product to be sprayed

First of all, you should choose your paint gun based on the type of product you want to spray.

• For varnishes and wood stains, opt for aircoat guns, specially designed for spraying thin, glossy products. This type of paint gun is particularly suitable for the automotive industry. 

• For conventional paints, acrylics, or latexes, as well as for heavy body, viscous products such as coatings or glue, you can choose any airless gun. This type of gun is particularly well-suited for construction industry painters.

High or low pressure?

The pressure needed for a paint gun depends on the type of work you plan to do.

• For one-off jobs on small surfaces, low-pressure guns are best. HLVP guns are recommended for small surfaces and are ideal for woodworkers and cabinetmakers.
• For painting large surfaces, opt for a high-pressure gun.

Flow rate

To paint or varnish a piece of furniture, you’ll need a low flow rate. On the other hand, to repaint the facade of a building, for example, you’ll need a high flow rate. Some paint gun models may have a non-adjustable flow rate. Paint guns without adjustable flow rates are not recommended because they are less versatile and cannot be used for various jobs requiring different flow rates.

Reservoir size

Reservoir size is important to consider for guns with a reservoir or cup attached to them. A larger cup will allow you to hold more paint and paint for longer periods of time. However, the gun will also be heavier, making it more tiring to use.

The spray nozzle

EXITFLEX spray nozzle

The spray nozzle is the part of the gun that sprays the paint (or other product). The nozzle can be easily changed since it needs to be adapted to the product being applied (viscosity, etc.). Flat or fan jet nozzles can be fixed or adjustable. Adjustable nozzles are recommended as they allow you to change the spraying direction.