When it comes time to paint, a wide range of possibilities opens up to the different tools offered today to spread the chosen paint or coating on the desired surface.
From the hand tools, like the always faithful Brush and the a little more sophisticated rollerEven the systems propelled by energy, both electric and pneumatic, the application of all these elements is vast and varied.
In Of Machines and Tools We have especially tackled the field of power painting tools and their accessories. In this way, we provide a broad introduction about electric paint sprayers and their maintenance, and we also present a very useful component such as the paint mixer and its applications.
Now we are going to turn our attention to the air operated painting tools, that is, those that generally have a pistol design and that need a compressor or a turbine to work, as we will see below.
The paint spray guns Or simply spray guns make it easy to finish any paint job in a fraction of the time and without worrying about dirty rollers, brush lines, dripping paint, or the hassle of trying to paint evenly various surfaces.
Depending, among other things, on the operating mechanism and the finish obtained, air-driven or pneumatic spray guns are subdivided into three groups:
- Conventional high pressure guns
- HVLP (High Volume Low Pressure) guns
- LVMP / LVLP Guns (Low Volume Medium Pressure / Low Volume Low Pressure)
In this video we will learn the differences between the three types of paint spray guns and what each should be used for.
Although the DIYer is often satisfied with a conventional gun that he will use a few times a year, the HVLP paint sprayers (“High volume and low pressure”) are much more desired by professionals who use them frequently and their cost is easily absorbed with the first jobs done.
So, let’s dive into the details about these highly sought after models to get to know them a little more.
What is an HVLP spray gun?
Intended for the professional user, HVLP paint guns are ideal paint spray equipment for use in touch-ups, finishing work, furniture staining, cabinet painting, and any detailed application where high precision, speed and precision are required. perfectly smooth finish.
And why are they ideal for this type of requirement? Because each of the working conditions of these devices brings its benefits:
- High volume: this means that a greater volume of paint comes out of the nozzle of the gun and hits the surface to be painted.
- Low pressure– This means that paint atomization is reduced, resulting in less overspray, less residue, and less contamination.
Therefore, if we combine these characteristics, the result is a more professional finish and a lower cost of painting.
In other words, and as we can see in the video, by employing a higher volume of paint and lower air pressure, HVLP guns can reliably control even distribution of paint. This will translate directly into savings, both in money by minimizing paint waste due to overspray and material splatter, and in time by not having to refine paint lines left by other devices.
How does an HVLP spray gun work?
The basic principle of HVLP guns is to “atomize” the paint, which means that when it comes in contact with the stream of air released by the gun, the paint separates into small particles as air is expelled from the tip.
All guns come equipped with unlimited paint fan build control from small to large (eg 180-250mm) as well as spray density controls from mist to thick coat. They also feature controls for air flow and paint volume, a paint reservoir of approximately 600 ml capacity, an air inlet and a nozzle that helps control the pressure and dispersion of the paint to be sprayed.
The operation is simple – when the gun trigger is pressed, the paint is released into the air stream, atomized and shot through the nozzle at the desired pressure and spray pattern. The result of a HVLP gun Properly configured it is a fast and even coat of paint, with very little material waste.
However. What is the paint drive mechanism on HVLP guns? Actually, this mechanism can be of two types:
Using an air compressor capable of producing about 25 psi to drive the paint. They are the most common because they are the cheapest, but depending on the work needs they may not be efficient enough.
Using a turbine system to produce large volumes of air, but with a lower pressure: approximately 6 psi. These types of sprayers They are more expensive, but also more efficient and since they do not require an air compressor to be purchased separately, they can save costs.
What are the applications of HVLP guns?
Precisely as it is the best-selling type of paint spray guns, the professional, industrial and even domestic application of the HVLP guns It is wide. Let’s look at some examples.
a) Car paint renewal
In this area, HVLP sprayers They have replaced the alternatives on the market and have become the best tool for auto body and paint shops. They can be used to spread the base coat in renovation of the original paint, as well as for the color coat and clear coat or varnish. Additionally, these guns are better suited than other options because no clear coat polishing is required. And while the HVLP sprayer It is indicated for professionals, DIY enthusiasts can also use it to renew their car paint in the home garage.
b) Marine finishes
Proper finish is essential for marine vessels because the coating provides corrosion protection and increases attractiveness. The HVLP sprayer It can work on metal surfaces and wooden surfaces. When the nozzle is properly adjusted, coverage of each surface is ideal. When using a HVLP gun For marine paint, it is important to ensure that the distance between the surface and the gun is minimum, about 10 cm. This will reduce overspray and provide good coverage. Reducing overspray will minimize the amount of paint particles in the air.
c) Painting of buildings
While the HVLP sprayers They are most popular for painting transportation structures, they can also be used for architectural work. They are ideal for painting different characteristics of buildings because the layer obtained is uniform. Additionally, almost all types of coatings can be applied, as long as the proper nozzle is used. For example, the HVLP gun can be used to apply even layers of caulk to drywall drywall. The device can be used for both indoor and outdoor applications, and once again, no overspray can lead to great savings.
d) Furniture finishing
This can be a tedious task because a high level of precision is required. Without the proper tools, the coatings will not be uniform and the visual effect will look lackluster. The HVLP sprayers They are suitable for this task because the paint is propelled at low pressure. This lower application pressure means that the gun can be held closer to the surface of the furniture and consequently the coating can be spread more precisely, giving better coverage than other alternative methods.
Advantages and disadvantages of HVLP guns
Like any tool, HVLP guns have a number of advantages, although they can also have their drawbacks. It is important to know both and then make an intelligent decision. In the following image we summarize the most relevant ones.
Do I need an HVLP spray gun for my job?
This is a question whose affirmative or negative answer will depend on a series of factors that we must consider beforehand.
Professionals know that the biggest cost in their industry is labor and time. The HVLP sprayers were precisely designed to save time, increase efficiency, reduce overspray and, thanks to the uniformity of the spread paint layer, minimize the possibility of having to spray an area more than once or dealing with unsightly splatters and lines . As if that weren’t enough, they have a long service life despite heavy use and this is due to the longevity provided by working at low pressure. However, like all technological advancements, good practice is required. The rookies of the HVLP guns they often complain of uneven “orange peel” finishes. But with enough experience, very soon you might even be surprised at how many uses an HVLP sprayer has.
The home user can start with a conventional high pressure gun and then evaluate, based on their requirements, whether it would be appropriate to replace it with an HVLP. Painting a house, for example, is one of the most embarrassing tasks that many DIY enthusiasts would rather not do on their own. But it is not necessary to spend a lot of money to acquire an HVLP pistol that adapts to the budget and needs of each user. This will make it possible to achieve identical or even better results than if you hired a professional painter to do the job.
It is also important to consider what type of coatings are to be sprayed. Both HVLP and conventional guns can handle a wide variety of materials, but high viscosity coatings such as lacquers, alkyd resins, sealants, etc., may require conventional guns instead of HVLPs.
Therefore, we must first consider the use, the frequency of use and the viscosity of the coating with which we will work. Once we have these options settled and we have decided on an HVLP pistol, a second stage will follow on how to select it correctly.
We will deal with it in a future article.