How to choose the correct spray gun

With so many different variables to consider when purchasing a spray gun for your project, it can often be difficult to know where to start.  You’ll find a huge range of different spray guns available, whether they be airless, gravity fed, suction, or pressure fed, but you’ll need to choose the one to best suit your requirements.

What is a spray gun?

Spray guns are similar to airbrushes but they generally use larger equipment and are used to cover bigger surface areas with an even coating of liquid. You’ll find hand-held as well as automated spray guns with interchangeable heads that allow for different patterns of spray, as well as high-end guns which can be customised and completely rebuilt. Every air gun has an air compressor, paint basin and nozzle. When you press the trigger, the compressed air and paint is mixed to break down the paint particles.  This is then released from the spray gun in a fine spray to cover your surface. We’ve highlighted a few of the most important variables to consider when picking the right spray gun.

 

HVLP, LVLP or conventional?

High volume low pressure (HVLP) guns allow a higher proportion of paint or coating to reach the target surface. Not only does this reduce the amount of materials you’re using (and wastage of materials), it also helps to prevent unnecessary over-spray. These types of guns are often used for architectural coatings, interior decor or furniture finishing.

Low volume low pressure (LVLP) guns are practically identical to HVLP guns but are among the best and most efficient guns on the market. This is because they minimise paint wastage and operate at a lower pressure, using a lower volume of air than HVLP guns. This decreases the amount of air consumed whilst increasing the proportion of air that reaches your target surface. However one disadvantage of LVLP guns is that they are normally more expensive than other types of spray gun.

 

Select the right nozzle for the job

There are a wide range of different nozzle types to choose from, but the three most common are flat stream, hollow cone and full cone nozzles. The type you choose will depend on the project you are working on – for example, for a fine finish over a larger area, a full cone nozzle may be the best option, whilst for a smaller area and a more precise result, you may be best selecting a flat stream nozzle.

 

Consider the CFM rating

You might see the CFM rating mentioned on spray guns and wonder exactly what that is. The amount of air needed to complete a project is measured in cubic feet per minute or CFM for short. This amount can vary greatly but all compressors will have a CFM rating, normally shown in the following way:

16CFM@ 90 PSI

This rating is the output level of the compressor tank, so the actual CFM at the gun can vary depending on the diameter and length of hose and fittings you use. Using a shorter, larger diamater hose and eliminating fittings means you will get more CFM at the gun for more precise results.

Consider the viscosity of your paint

Whilst viscosity is generally measured as low, medium or high, you may want to check technical information for your paint as a specific spray gun may be recommended. Some guns are more suited to heavy viscosity coatings. Generally speaking, the finish you are looking for will affect your choice of gun. Bear in mind that a conventional gun uses twice as much paint as an HVLP gun.

What are your production requirements?

In other words, how fast do you need your gun to spray?  Using larger air caps and fluid nozzles can speed up your productivity. The higher the CFM of the air cap, the heavier the viscosity of coating it is able to atomise.  For high volume painting projects, using a pressure pot to feed your spray gun is ideal, giving you greater air pressure control. For the ability to paint continuously, a diaphragm or fluid transfer pump may be best. Low viscosity paints and small scale projects can use a gravity or syphon feed spray gun. In some cases, you may find an airless spray gun is the best option.

Lastly, consider the diversity of your gun

Think about how often you are going to use your gun and the types of projects you will be working on. When it comes to spray guns for sale, it is often worth investing more in a high quality gun such as a Graco spray gun, as these generally have more choice of fluid nozzles and air caps, and can usually be totally rebuilt. Lower cost guns suffer from limited set ups and are often not rebuildable.

To find out more about choosing the correct spray gun for your requirements, call one of our sales support technicians on 01302 856666 or contact us here.  We’d love to help!

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