How To Choose A Spray Gun: Professional Advice

• What is the difference between an electric spray gun and a pneumatic
• Our combat kit: FIAC COSMOS 2.4 plus MIOL 80–864
• How to choose a gun for a pneumatic spray gun using spray technology
• How to choose a compressor
• Electric spray gun: manual or floor
• Characteristics of electric spray guns

The first atomizers appeared at the end of the nineteenth century. It is interesting that they were used in medicine - for treating open wounds with various preparations, as well as for inhalation of the throat and upper respiratory tract. The invention turned out to be incredibly successful and quite versatile, so its author, American Alain DeVilbiss, left medicine and organized the production of spray guns. Alain and his son patented a manual spray gun for industrial and domestic use in 1907.

As you can see, this tool has a long history. For many years, it has been appreciated not only by furniture makers, industrial painters and auto repair workers, but also by builders engaged in finishing work. Earlier in our country there were no household spray guns, almost none. You probably saw how at one time women from the housing office whitewashed the entrances with spray guns with a hand pump and a long metal fishing rod. Do you remember the Soviet vacuum cleaners that work on blowing, they also came with a plastic nozzle in the form of a lid? We connect a half-liter can of paint and …

Now everything is a little different, the tool has noticeably evolved, it has become more functional, more productive and more technological. Modern sprayers allow you to quickly carry out a huge amount of painting work, in addition, they provide the highest quality of the finished coating. If you need a smooth, evenly painted surface, then there is no alternative to the spray gun at all. Neither a roller (even with the smallest velor coat), let alone a brush, will give such a result. An indispensable spray gun will be when processing large areas or when painting profile, curved, volumetric parts.

At the moment, there are many options for a paint sprayer, which differ not only in price, but also in a special design, different principles of action. Accordingly, their purpose is different. All spray guns fall into two main categories:

1. Pneumatic.
2. Electric motor, airless.

What is the difference between an electric spray gun and a pneumatic

Let's be honest, they don't have much in common. Here it is in the design, and in the principles of work. A spray gun that runs on compressed air is called pneumatic. Naturally, a compressor with a receiver is needed for its operation. Through a hose, a spray nozzle in the form of a gun with a tank is attached to the compressor - in fact, this is the spray gun. The compressor, using electricity, pumps air and supplies it to the spray gun. Pressurized air breaks the paint into tiny particles and pushes it out of the nozzle, forming a so-called torch.

A properly selected, high-quality "compressor-spray gun" kit costs a lot of money, so pneumatic spray guns are mainly used by professionals.

An electric spray gun (more precisely, it will be called "with an electric motor") does not form compressed air, paint is sprayed simply under pressure - using a built-in pump. Naturally, paints and varnishes cannot be properly shredded due to lack of air flow. The quality of the coating performed by such a device is significantly inferior to the result available when using even the cheapest pneumatic analogues. True, in return we get a compact, inexpensive, easy-to-maintain instrument that does not require any additional equipment or air purification means. He is able to seriously make life easier for a home craftsman who periodically encounters painting work. The vast majority of experts consider electric spray guns to be household.

In fairness, we note that there are electric spray guns with a mini-compressor. This is a kind of intermediate option. Here, the compressed air flow is also used for the spraying process. The compressor is clearly designed for the performance of your pistol, it is made in a separate casing, they are connected with a special factory high-pressure hose. The spray gun that we hold in our hands is much lighter than the usual monoblock electric model (no electric motor). Such copies are close to traditional pneumatics in terms of painting quality, however, they are not cheap - the price tag starts at 500 conventional units. Be careful, through television (all sorts of "shopping from the couch") are now actively spreading low-grade stylization for this class of professional instrument.

Our combat kit: FIAC COSMOS 2.4 plus MIOL 80–864

At one time, our team also faced a question of choice. We decided not to play roulette, and followed the example of our more experienced comrades - we bought a decent, one might say, typical Italian mid-level compressor FIAC COSMOS 2.4. He was paired with a simple high-pressure pistol from a well-known Kharkov company - MIOL 80-864. The set turned out to be well balanced, there has never been a case when the compressor shuts down for a "resume", or a thermal relay has triggered due to overheating. Its productivity of 240 l / min easily covers the "gluttony" of the pistol, which is estimated at 75-210 liters per minute.

There were doubts about the capacity of the receiver - which one to take, 24 or 50 liters. As usual, we made a choice in favor of compactness, low weight - and did not regret it. The COSMOS 2.4 model is only 65 cm in length, 30 kg in weight, good ergonomics, and very easy to transport across the floors of our facilities. Despite the minimum volume of the receiver, the pressure of 4–6 bar (the working pressure of our pistol) COSMOS 2.4 keeps stable, without failures during active parsing, since its automation is set to a range of 6 to 8 bar. The developers of the company "Fiats" used not the weakest engine (1.5 kW), but it works stably and not too loudly. Its aluminum casing with pronounced ribs dissipates heat well, and the built-in fan contributes to this. It is quite natural that the Italian apparatus has an understandable pressure regulation, a high-quality pressure gauge,really working safety valve, sensitive thermal protection. Our compressor has one drawback: after a work shift, several drops of oil are found on the floor - apparently, some kind of gasket "sweats". But we decided not to intrude on the motor, because it has not let us down for several years in a row, we just always underlay something.

A little about the MIOL 80–864 pistol. We don't paint cars, we don't varnish windows / doors, so we didn't bother too much and bought an inexpensive high-pressure spray. But the quality of the coating that it allows you to get will completely and completely suit any builder. At the same time, it works quite quickly, hiding power is good, a small percentage of paint transfer does not scare us (consumption is better than from a brush or roller). It is lightweight, maneuverable, it fits well in the hand, however, it lacks a little rubber or something similar on the handle. Sometimes you want to have a larger tank (the kit comes with a 0.6 liter tank), but logic dictates that then you will need to hold more paint in your working hand. Manufacturers installed a nozzle on the pistol with a diameter of 1.5 mm, and it completely satisfies us, we don't see any sense in buying other sizes. We spray with this gun not only water-soluble paints, varnishes, but also more viscous materials - primers, drying oil, sometimes enamels. In general, we thought that we were buying a disposable ("break down - throw out - buy more") pistol in order to understand the principles of working with a spray gun, but it has been making us happy for several years.

From the very beginning, the compressor and the gun were connected with a polyurethane twisted hose MIOL 81-333. However, he turned out to be not entirely convenient for work "on site", he was constantly confused and strove to catch hold of something. As a result, it was replaced with a regular straight hose from old stocks. The problem has been fixed.

Our pneumatic kit turned out to be very budgetary. He copes with all the tasks set easily, the best for construction is not needed. Basically, all maintenance is reduced to dumping moisture from the receiver and regular cleaning of the gun (in time no longer than washing or preserving the roller). Now it's hard for me to understand how some people who are seriously involved in repairs do without a spray gun.

How to choose a gun for a pneumatic spray gun using spray technology

If in spray guns with electric motors the manufacturer balanced the performance of the pistol and the injection motor in a single monoblock tool, then in the case of pneumatics we can independently choose (have to choose) both the parameters of the spray gun and the characteristics of the compressor. What is most interesting, the main part is the spray gun (pistol), and based on its performance, the compressor is selected.

There are three types of spray guns, depending on the working pressure and the volume of consumed air. They were simply named: HP, HVLP, LVLP.

HP technology (an abbreviation from English for "big pressure") is used in instruments of a low price level. At the moment, for a number of reasons, it has receded into the background, or more precisely, into the background. What is its peculiarity? The main thing is a high level of working pressure, reaching 5–6 bar, with a relatively low air flow. Such a spray gun allows you to paint quickly, but high pressure is an obstacle to perfect quality. The main disadvantage of HP technology is the low percentage of material transfer. An interesting term, isn't it? It means in what percentage the paint gets on the object, and how much it evaporates with the air stream. So, these devices carry no more than 45-50% of paints and varnishes, the rest we throw out under pressure, as they say, to the wind. It turns outthat not only is expensive paint wasted, but the air in the work area is also polluted. As a result, in some countries, environmental organizations have banned the use of such spray guns. These tools are good for their simplicity and budget cost. High pressure guns are perfect for most repair and construction jobs involving spraying of various compounds.

HVLP technology ("high air pressure - low pressure") - is considered to be the most effective. The air at the inlet to the gun is under high pressure, and at the outlet it is sufficiently discharged (0.7–1 bar). The ink transfer coefficient rises to over 65%, and of course the quality of the work also improves. All this is due to the excellent stability of the torch, the specific design of the spray gun, its high-tech nozzle and special air channels. HVLP pistols are very economical, but they are also expensive.

Pneumatic spray guns LVLP ("little air - low pressure") have the best transfer - up to 80%, respectively, the loss in the form of fog is reduced to 20%. At the same time, they do not require a large amount of air, so the requirements for compressor performance are not the most stringent. You only need about 180-200 liters per minute. Oddly enough, the speed of work will not suffer, the quality of spraying will also be excellent.

There are a few more nuances. For example, the location of the container for paints and varnishes. The top location of the tank gives a good weight distribution and speed of work. The containers located on top have a small volume (up to one liter), they are usually made of nylon or plastic, often transparent (they allow you to control the level of the material). The lower tanks are larger (1 liter or more), they are often made of metal. During the break, the gun can be placed on such a container.

Spray gun manufacturers often offer replaceable nozzles of different diameters - from 1 to 3 mm. For spraying building mixes, nozzles with a hole up to 6–7 mm can be used. Depending on the type of sprayed material, its grain size and viscosity, in fact, the nozzle is selected. Nozzles with an orifice of 1.4–1.7 mm are considered universal.

It is worth paying attention to the possibility of adjustments that affect the spraying process. This is limiting the stroke of the needle (the amount of paint supply), setting the parameters of the outgoing air, adjusting the shape of the torch. Some models are equipped with a pressure gauge.

How to choose a compressor

The compressor is the most important part of a pneumatic spray gun, so in order to assemble a truly capable kit, you need to competently approach its choice. There are several indicators by which compressors differ from each other, some of them are traditional for most models, while others make us think seriously.

The engine power of most compressors on the market ranges from 1.2 to 1.8 kW. This is quite enough to ensure good performance of the entire unit. The motors on average compressors are even outwardly very similar, one might say, identical. Unclean manufacturers may declare clearly overpowered, although their compressors do not actually deliver more pressure or more air. They are driven by the desire to make the product more buyable, they should not spend extra money for non-existent or unnecessary watts.

The receiver volume of 24-50 liters is already a tradition. For construction purposes, this is what you need - the accumulated air will be enough for most types of work, while the apparatus remains moderately compact and light. But if the compressor will be used in some kind of production, in intensive mode, then the budget option may not be enough - you need to pay attention to the larger volume of the receiver (100-500 liters). In fact, a larger receiver can compensate / increase the overall compressor capacity to some extent.

Operating pressure. Usually, there is no need to choose here - the vast majority of compressors compress the air in the receiver to 8 bar, after which the automation turns it off. Manufacturers set the lower threshold (switch-on threshold) at 6 bar, when this indicator is reached, the motor switches on and "pumps" the missing volume of air into the receiver. More advanced units pump 10 or more bars.

Performance. And here is more attentive. This concept reflects how many liters of compressed air the compressor produces per minute. Why is this so important? We have already said that guns differ in spraying technology, for normal operation they need a different amount of air, different pressure. Let's say HVLP spray guns "consume" a lot of air (180 to 550 l / min). If the compressor is selected incorrectly, then the pressure drops too quickly, even with the constantly running engine, it “floats” at the outlet - the quality of atomization deteriorates noticeably. We'll have to take frequent swap breaks. If the motor seems to cope, but works at the limit, then it may overheat and, again, turn off the automation (thermal relay), in addition, we have premature wear of the piston group.

Interestingly, manufacturers indicate inlet performance (how much air is sucked in). In practice, air losses occur during compression, and they amount to 35%. Experts believe that for a guaranteed correct calculation (the actual volume of air at the outlet), we must multiply the declared performance by a factor of 0.65–0.7. It turns out that the common 206x0.65 = 133.9 l / min. Most manufacturers are a little more loyal in this matter, they offer to do the calculation with increased productivity - at least 15% of the pistol's gluttony.

One conclusion suggests itself: compressor performance is the most important indicator that must be taken into account with a margin.

Important compressor options include: the presence of an automatic shutdown in case of overload, pressure adjustments with a pressure gauge and a safety valve, built-in filters and cooling fans, an ergonomic layout with comfortable handles and wheels (for compact mobile models).

Electric spray gun: manual or floor

Electric (airless) sprayers are available in both manual and floor versions. A manual spray gun is the most affordable and most common version of this class of power tools. Because of its characteristic sound and vibration, it is also called the “buzzing pistol”. In this case, the entire unit is arranged in one unit, consisting of a motor with a piston pump, a pistol grip, a reservoir and a spray nozzle (valve, nozzle …). Many companies produce such a tool, some of them have succeeded more, some less, but the fact remains that these are household spray guns for work from the category of "do it yourself". The firm "Bosch" did not deceive the consumer and sells all its painting tools in green "household" cases. The vast majority of hand held electric spray guns have relatively low paint consumption (transfer) efficiency,spray quality is often poor. However, we cannot but be won over by the high speed of painting works, ease of use, compactness and low price of such a tool.

Floor spray guns are produced by a limited number of companies: Campbell Hausfeld, Wagner, Earlex. Such units are distinguished by high technical characteristics inherent in a professional tool. They have a more powerful and heavier motor (you don't need to hold it in your hands), a productive pump, an extended set of adjustments, a greater margin of safety, which allows you to use the tool for commercial purposes - for painting serious volumes (wooden and metal structures, ceilings, walls …) … We only control the gun connected to the high pressure hose - the power unit and the reservoir are mounted separately on the bed (for example, the Wagner Paint Crew model).

Characteristics of electric spray guns

As we already said, the developers have already balanced the main indicators of the tool related to performance, they all turned out to be plus or minus similar. It makes no sense to choose specific specimens based on minor differences in engine power or pump operating pressure. Believe me, extra watts will not play a role, but the rest is worth understanding in detail.

First of all, when choosing an electric spray gun, pay attention to what formulations it is intended for spraying. Some of them can work only with water-soluble painting materials, others are more versatile, they can easily cope with solvent-based paints and varnishes, oils, viscous compounds.

The presence of adjustments is a very important position. Most hand-held electric spray guns have a minimum of regulatory options. As a rule, this is a rough setting of the volume of supply of the painting material and the shape of the torch (Black & Decker BDPS200 or "Fiolent" KR1-260). More advanced models can have electronic adjustment of the feed, the ability to preset the working pressure, change the speed of the piston, several spray modes. Floor standing sprayers are usually more functional (Earlex HV500 SprayPort).

Pay attention to the type of tank. The most convenient will be transparent plastic tanks located at the bottom - they have a larger volume and allow you to control the amount of remaining liquid (BOSCH PFS 65). For extensive work, the built-in tanks will be too small, so it makes sense to look at models with the possibility of drawing paint from a free-standing tank. By the way, floor spray guns have large tanks of 7-10 liters or suck the composition directly from the bucket (Wagner ProjectPRO 117).

Some manufacturers make special extensions for their spray guns or long guns, sometimes with a swivel mechanism. This makes it possible to paint most surfaces without ladders and scaffolds. Imagine that you need to process the ceiling, but you need to keep the tool at a short distance from the plane. Speaking of distance, there are spray guns with a laser designator showing the working distance - very convenient for beginners. Here again the company "Wagner" distinguished itself (model Wide Shot).

Floor sprayers may have different hose lengths - from 1.5 meters (Miol HVLP 79-560 - shoulder-mounted version) to 60 meters, sometimes this difference greatly affects convenience and productivity. The paint composition can be transported over a limited distance. For example, the DP Airless DP-6820 can feed material 30 meters horizontally and 15 meters up.

It is very important how high-quality plastic is used for the manufacture of the spray gun, how many metal parts the manufacturers used (it is better if the needle is made of metal), how well all the elements of the tool fit, especially the movable ones. There are usually no repair kits for electric spray guns, a breakdown will immediately entail a replacement tool.

The vibration of a handheld electric spray gun can be very strong. Before buying, turn on the tool, take the opportunity to compare several models, this will also allow you to decide on the correct ergonomics of the product for you. Pay attention to the weight of the tool.

Give preference to products of a well-known, time-tested brand. Overpaying for a brand will likely save you the hassle and downtime.

We all love to paint, because it is at this stage that the objects of our works acquire their special features, a finished look. The sprayer is the tool that will bring true pleasure from work, you just need to choose the right one for your specific purposes.