What is the correct choice of the spray gun? It is a tool designed for use in the field of automotive painting. The principle of its operation is similar to the spray gun, that is, paint is sprayed due to the pressure of compressed air. Today there are many designs. Outwardly, of course, such tools are similar to each other, but if you look inside, you can see how different their paint supply systems are. Depending on the requirements for painting, you can choose one or another model of the tool.
Spray gun conveniently and quickly, you can paint the car or other metal, and wooden surfaces.
The selection of the spray gun should be carried out after the understanding of its device has been formed. Regardless of the model, such a device has mandatory systems:
The principle of operation of the spray gun is based on the ability to capture and carry air droplets of liquid paint in a jet of air.
- Air supply adjustment. Outflow pressure regulation depends on this system.
- Torch-shaped gearbox. This system regulates (during painting) the optimal shape of the sprayer.
In accordance with the technical characteristics of the spray gun has the following classes:
- High Transfer Efficiency is an abbreviation of HTE. The equipment having such marking has high transmission efficiency.
- Low Volume Low Pressure is an abbreviation of LVLP. This model spray gun has a low rate of pressure and volume.
- Reduced Pressure is an abbreviation of RP. Technique with reduced pressure.
- High Volume Low Pressure is an abbreviation of HVLP. Such marking indicates that the apparatus has a high working volume, but low pressure.
- High Pressure is an abbreviation for HP. High pressure equipment.
- Middle Pressure is an abbreviation of MP. Airbrush medium pressure.
- Low Volume Middle Pressure is an abbreviation of LVMP. Unit with low volume and medium pressure.
Each of the above systems has its own characteristics, which can be both positive and negative. This, in turn, can significantly affect the choice of such technology.Back to table of contents
High pressure system
The popularity of the High Pressure system is due to the ability of such a brand to give an output pressure of 1.5 atmospheres. It is possible to work with the indicator from 2.5 to 5 atmospheres, while there is a low air flow rate, which is 100-300 l / min.
The device spray gun.
The positive aspects of the system are as follows:
- The wide size of the torch allows you to evenly paint the surface.
- Terms of work in painting are significantly reduced.
- Such a system is different in that most of the paint is not used for its intended purpose. Approximately 2/3 of the material being painted simply flies away to nowhere due to the “rebound” from the working plane. This is a consequence of too much pressure. As a result, "haze" is formed and all surrounding objects become colored.
- Strong pressure contributes to air turbulence. As a result, light surrounding debris sticks to the work surface along with paint. Therefore, each painting is accompanied by subsequent grinding and polishing.
High Volume Low Pressure System
Classification spray guns.
Such models of spray guns have a special design of air channels, thanks to which (unlike the first analogues) 65% of the paint remains on the surface. The outlet pressure is about 0.7 atmospheres, and 2.5-3 atmospheres at the inlet.
This technology saves paint. The whole process of applying the material occurs at a distance of 12-15 cm.
- The opportunity to save on the consumption of materials.
- No adverse effects on the environment and human health.
- During operation, no mist is formed from paint.
- On the painted surface does not stick a lot of garbage.
Disadvantages of HVLP:
- For such a gun, a powerful compressor is needed, as it consumes from 360 liters of air per minute.
- The diameter of the duct is slightly increased.
- Due to the presence of a powerful compress, you should install additional filters to clean the air from the impurity of oil and moisture.
- Such a brand of technology requires skills in work, since it depends on the smoothness of movements whether stains will form on the surface.
- Low pressure leads to the fact that such a device does not reach some places for painting.
Low Volume Low Pressure System
Comparison of forms of spray paint.
This brand of spray guns is one of the latest developments. In general, such a system can be described as combining the previous two. It does not have those inconveniences that are present in the HVLP and HP.
The outlet pressure may have a mark of 0.7-1.2 atmospheres, while at the inlet this indicator may have a value of 1.5-2 atmospheres. When air consumption in 150-350 liters more than 65% of the paint remains on the surface, and not in the air. Such an apparatus can be operated at a distance of 20-30 cm, which is much more convenient from the point of view of hard-to-reach places.
Advantages of this marking:
- working air consumption is significantly reduced;
- a sufficient amount of paint is used for its intended purpose;
- This type of spray gun is practically insensitive to the pressure drop of the compressor.
There are no flaws in such a system.
The remaining systems are simply different combinations of the previous three.
Paint and varnish material can be fed into the instrument in two ways. In the first case, a hose attached to the equipment is involved. It increases the pressure. This method is convenient to work with large areas. In the second case, a special small tank is used. It is designed for a small amount of painting, as continuously with such a tool you can work only for an hour.Back to table of contents
Main selection criteria
The choice should correspond to the needs of the painter. Masters usually have at hand from 3 to 5 models.
The best option for home use is the Low Volume Low Pressure system tool. This takes into account a few more nuances:
- Power. Depending on the power, it is necessary to select the appropriate system. For example, the compressor of the HVLP system will not be able to provide the necessary volumes of air at low power technology.
- Cross section of a nozzle. In order to determine this parameter, you should know the performance of the selected model. If you use different nozzles for each layer (even with a difference of 0.1 mm), this will immediately become noticeable on the surface.
In addition, the viscosity of the working material will also affect the selectable part diameter:
- base coatings of the type "metallic" - 0.12-0.13 cm;
- lacquer materials and acrylic paints - 0.14-0.15 cm;
- acrylic soils - 0.15-0.17 cm;
- putty liquid consistency - 0.17-0.2 cm.
In addition, primers require their own nozzle. Therefore, in a professional workshop usually there are several sets available.
Factors to be paid to when choosing a tool:
- The model of the spray gun must have air consumption, which is not higher than the performance of the compressor.
- Price. Here we should build on our capabilities. But keep in mind: a well-known manufacturing company is a guarantee that the product complies with the specifications stated in the documents.
- Purpose of the tool. If you plan to use the spray gun for amateur purposes, then there is no point in acquiring highly powerful models. But if you are engaged in painting at a professional level, then the choice will be turned in a completely different direction.
- You can choose among hand, pneumatic or electric tools. In the first case, control comes at the expense of a manual drive, which makes such a tool popular. But the second option has a higher functionality. Despite the fact that the pneumatic spray gun is suitable for serious use, the paint consumption in it is large enough. As a compromise solution, you can choose a combined technique. But in this case, you should immediately be ready to pay a significant amount for it.
As for the latter, such a device works by plugging it into an outlet. It has good functionality, great for painting large surfaces.Back to table of contents
Recommendations for the acquisition of the gun
Depending on the scope of application should pay attention to the flow of paint and varnish material.
As mentioned above, a pump can be installed on the machine, which will supply paint to the hoses. This method is suitable for monochrome staining.
There may be lower and upper tanks. The first option is acceptable for work with great details, but the second option is convenient for the possibility of changing colors.
When choosing a spray gun should take into account personal preferences. For example, if there is a habit of working with a particular brand of manufacturer. Many try to buy the equipment of only one brand. Even at the stage of selection it is recommended to take the instrument in hand This will help to feel its convenience, because most often painting takes a long time, so the hands can quickly tire.