Painting jobs are often liked by many fans who take advantage of a weekend or even their vacation to get down to work and change the face of their home. For their part, professional painters or operators of various tasks such as blacksmithing, veneering, carpentry and others that involve the application of paint, always look for means and tools that make your task easier and increase productivity.
It is very true that current technology has developed numerous paint application devices that are leaving behind traditional brush and roller methods. Those involved in auto paint and sheet metal jobs, for example, have pneumatic paint sprayers that achieve a perfect finish in just a few hours. Like any pneumatic tool, paint sprayers only need the inevitable shop compressor to provide them with the air they need to function.
It is worth wondering if paint sprayers They are also marketed as power tools, so that they are accessible to other users (for example, at home) who do not have a compressor and do not want to buy or rent it for a painting job. In that case, this article will give us good news, because here we will know the paint sprayers electrical systems Or simply paint spray guns that we can acquire commercially at a reasonable cost.
How does an electric paint sprayer work?
The secret of everything sprayer is to produce the atomization of the fluid to be sprayed, that is, to convert it into small droplets that are what form a fan spray pattern.
There are various ways to achieve atomization of this fluid, in our case, paint or related materials. Thus, while pneumatic sprayers Injecting compressed air into the paint, the electric guns pump the paint at high pressure by means of a motor, expelling it quickly through a nozzle.
The following figure shows the atomization process produced by a electric spray gun.
The high pressure forces the paint through the device’s small nozzle, emerging as a solid stream (known as a “foil”) at high speed. When that solid jet collides with air it begins to disintegrate, initially breaking up into fragments and ultimately into very small droplets that form the fan-shaped pattern.
The advantages of electric paint sprayers There are several, but professionals and amateurs point out these three as the main ones:
- Speed: They are faster than tires, so more jobs can be completed in less time and with less labor, without relying on a compressor. Compared to traditional methods, they are up to 10 times faster than brushes and rollers.
- Quality: produce a uniform coat of paint on all types of surfaces, leaving a consistent, high-quality finish.
- Versatility: They can be used for a wide range of cladding materials, including indoor and outdoor jobs, and can be easily transported from one location to another.
What is an electrical paint sprayer system?
Like any system, it is to be expected that it involves several components in addition to the spray gun proper. To this end, this illustrative video shows us one by one those components.
Now let’s complement the video, taking a closer look at each of the elements that we have just seen.
- Air cap retainer
- Air cap
- Lock lever
- Control of the amount of paint
- Trigger unit
- Handle to hang on the wall
- Filter cover
- Container for paint
- Connection for power cord
The system is completed with the delivery of one or more replacement nozzles, a brush, a nozzle cleaning needle or awl with its corresponding «T» adapter and a paint viscosity measuring container, which we will see later. why and how it should be used.
Of all these components, we are going to deal with a little more than two: the motor and the nozzle.
Depending on the manufacturer, the motors that include the electric paint sprayers They can be of three types: universal, alternating current or direct current, in the latter case, with or without brushes.
Universal motors are the most economical, but due to the high number of revolutions per minute they present (between 10,000 and 20,000), and despite being cooled by a fan, they have the shortest useful life. On the other hand, AC motors, although they last longer, require a constant and permanent power source to function properly, and can overheat if used under certain circumstances.
Therefore, DC motors are generally preferred, which better withstand power fluctuations because they can operate at variable speeds. Within these, we have models of sprayers equipped with motors with carbon brushes and models brushless, that is to say, equipped with brushless motors. The latter are heavier and more expensive, but offer a number of advantages and reduced maintenance compared to their brushed pairs.
Although the vast majority of electric paint sprayers They are models with cable, we will also find cordless cordless sprayers, which, like many other electric tools, have comfortably established themselves on the market. In Machines and Tools we have already pointed out the particularities of corded and cordless tools, and in this article we present a summary of this, according to which each user will be able to choose the technology of their convenience.
This small interchangeable piece shown in the figure below has a great role in the system, since:
- Determine the fluid flow, that is, the amount of paint applied.
- It determines the spray pattern (fan width), so selecting the correct tip is an important decision.
Commonly made from high quality tungsten carbide, the nozzles are rated in terms of orifice size. The amount of paint that flows through the sprayer depends on nozzle size and pressure setting. There are different nozzle sizes depending on the type of paint to be used. For example, lacquers, stains, and enamels are lightweight coatings that are sprayed with small diameter nozzles, while latex exterior paints are much denser coatings that require larger diameter nozzles.
Some sprayers They are designed to accommodate one or two specific nozzle diameters, typically 2 and 2.5mm, for less viscous and more viscous paints, respectively. These diameters are suitable for solvent and waterborne paints, varnishes, primers, clearcoats, wood protectants, and vehicle undercoats and topcoats. However, these diameters should not be used to spray acidic and alkaline substances, materials that contain particles, latex paints, or paints that do not drip or splatter.
a) Material dilutions
Even when using the proper nozzles, most paints must be thinned out before spraying. Since the label on the paint can does not always contain instructions for dilution, some paint manufacturers sprayers They include a viscosity meter in their system to guide the user on how to achieve the proper viscosity.
The technique of using the viscosity meter is simple. First, the paint is placed in an appropriate container and gently shaken until it is properly mixed. The viscosity meter shown in the figure below is then completely immersed in the paint container, then lifted to allow the paint to drain out of its hole.
A stopwatch measures the time it takes for the paint to flow through the hole in the meter. As soon as the continuous flow is interrupted, the stopwatch stops. This is the drip time measured in seconds, which should be adjusted to the one described in the following table.
If not, the paint is thinned again and the measurement process is repeated until the recommended drip time is achieved.
b) Spray patterns
Depending on the orientation of the surface to be painted and the amount of paint to be used, the spray guns they offer us several alternatives.
On the one hand, the air cap-nozzle unit can be adjusted to achieve three different spray formats. Simply loosen the air cap retainer and rotate the air cap to the desired position, as shown in this figure.
In this way, we achieve three different spray patterns:
TO – Horizontal fan jet: for vertical surfaces.
B – Vertical fan jet: for horizontal surfaces.
C – Circular jet: for corners and edges, as well as hard-to-reach surfaces.
It is also possible to regulate the amount of paint that we want to apply. To do this, turn to the right (more quantity) or left (less quantity) the knob indicated with the green ring in the following figure.
When is it recommended to use an electric paint sprayer?
In accordance with all the benefits and advantages that we have just pointed out, the use of a paint spray gun it is better suited for some occasions than others. If we are undecided, we can consult the following infographic recommended by the experts that will serve as guidance.