When painting a car, of any complexity, is coming up, for better and more economical painting, it is better to use an electric spray gun to paint the car. This device has the ability to adjust the paint supply speed, pressure and shape of the supplied jet. Distinctive features of an electric spray gun from a conventional one are: the ability to regulate paint consumption and the type of flow, not only in manual mode, but also automatically.
Types of electric spray guns
At the moment, there are quite a large number of types of spray guns on the equipment market for painting a car, and making a choice between them is quite difficult.
Basic parameters for selecting a spray gun
Types of electric spray guns
1. Depending on the work you will perform with it - applying primer, painting, applying varnish - you will need spray guns with different nozzles. If the viscosity of the coating used is 18-22 seconds, then you need nozzles with a diameter of 1.3-1.4 mm, and if the viscosity is 30-35 seconds, then the nozzle diameter is 1.6-1.8 mm; 2. There should be six holes on the spray head, except for the central one; 3. The spray gun must have two adjusting screws - for paint and air. 4. Location of the paint tank:
- The upper location of the paint tank enters the gun by gravity, under the influence of gravity, which ensures full use of the paint; it is lighter because it is made of plastic. But this tank has the following disadvantages: small volume (0.68 l) and paint can flow unevenly and slowly into the console, this slows down the work process and affects its quality.
- The lower location of the tank allows the paint to flow into the gun, for painting a car with an electric spray gun due to vacuum, a larger volume (1 l), uniform and quick application of paint. Disadvantages of this arrangement: the tank is heavy, made of aluminum, and paint is not fully used.
5. Package Contents: Many spray guns do not come with anything else except their main parts; you have to buy everything yourself. But more expensive models come with a paint filter, universal wrenches, and additional nozzles.
6. Cost of a spray gun; cheaper models can be used for one-time painting, or painting small volumes in inconspicuous places, since such models, as a rule, do not supply and distribute paint so well.
Depending on the parameters that you need, you can choose the brand of device for painting a car with an electric spray gun.
Choosing a tool - what to focus on
If you are going to purchase a paint sprayer, pay attention to the name. It usually begins with an abbreviation, according to which instruments are divided into three types :
- HP – models with high (in the range of 2.5-4) pressure, which is converted to low pressure at the outlet. This indicates that the tool will work with a large supply of air;
- HVLP, LVLP, RP are low-pressure tools, they consume a small volume of air and are economical in terms of paint and varnish consumption;
- MP, LVMP, HTE – devices with medium (0.8-1.2) pressure and are distinguished by their versatility.
Take a closer look at the size of the nozzle of an electric spray gun for painting a car - its small size ensures a fine-grained spray of the paint and vice versa. The attached instructions for using the tools provide complete information about the types of paints and the sizes of tool nozzles required for their application.
Popular models of electric spray guns today
- The WAGNER Project 115 is a 625W piston pump that delivers paint at a maximum speed of 0.8 l/min and a maximum pressure of 190 bar. Includes a 7.5 meter hose and a 9.5 liter paint tank. The WAGNER W 450 SE is a piston pump with a power of 110 W, paint is supplied at a maximum speed of 350 g/min, at a maximum pressure of 180 bar, a paint tank with a capacity of 0.8 l.
- Electric spray gun P PSP 1000 with a power of 1000W, has 2 adjustment modes, comes with a 4m long hose and a 0.9l paint tank.
- PSP 260 power 60W, productivity 260g/min, pressure 160bar, maximum paint viscosity that can be used 80 DIN/sec, tank volume 0.75l. The kit includes a measuring container for determining viscosity, a sleeve for circular spraying of paint with a diameter of 0.6 mm.
- Miol HVLP 79-560 power 600W, productivity 1650ml/min, pressure 0.13-0.7 bar, paint tank 1 liter.
- Bosch PFS 65 power 280W, productivity 130 l/min, paint capacity 0.60l.
For proper operation of the device for painting a car with an electric spray gun, you need to configure it. First, to set up the spray gun, you need to test it. It consists of the following tests:
- spray quality test;
- test for the correct shape of the torch imprint;
- test for uniform distribution of paint in a torch.
Spray gun test for spray quality
Spray quality test
It is carried out like this: we quickly carry out a spray gun, in paint spraying mode, along a sheet of paper or plywood at a constant and recommended distance for this type of air cap. We study the size of the droplets in the resulting strip. Do not try to achieve extremely fine droplets of equal size. Remember that the size of the droplets depends both on the force of atomization, which is associated with the air pressure supplied to the spray, and on the amount of pigment grinding.
A uniform distribution along the trail of droplets smaller than the rest can be considered normal. A print can also be considered normal when the size of the torch drops slightly decreases from the center of the print to the upper and lower areas of the strip.
Remember to use the lowest amount of air pressure required to achieve the desired atomization of the material. Excessively high pressure will lead to paint loss, more contamination of the spray booth, so-called “dry painting” and, ultimately, to poor paint quality.
Advantages of an electric spray gun
There is only one plus - the price. Such a tool can be bought for 1,500 rubles. This is much cheaper than professional car painting equipment. Even if you buy an electric spray gun for 15,000 rubles, it will still not be suitable for completely painting a car. An electric spray gun will make everyday work easier and help save time for builders, but for car painters it is almost useless.
However, even the low price of this equipment is not a clear advantage. The low quality of painting of body parts and the inability to work with materials of different consistencies greatly reduces the attractiveness of such equipment even for amateur motorists.
It is also useful to read: Rules for choosing a spray gun for painting a car
Torch imprint correctness test
Test of the correct shape of the torch imprint
Holding the spray gun motionless at a distance of 15-20 cm from a sheet of paper or plywood. “Turn on” it for about 1 second - until a well-defined torch imprint appears on the surface. Inspect the mark for any ridges or valleys that may cause uneven coloring. Carefully inspect the bottom and top of the print: if there is an excessive supply of ink, there will be ink splashing here.
Remember that in most cases the cause of an irregular spray pattern is not a damaged air cap or nozzle, but an unbalanced air to paint ratio. In particular, a torch with paint of low viscosity and a low solids content always spreads from the profile more easily than a high-viscosity material with a significant dry residue. A solution to this problem can be to reduce the air supply to create a torch by using the appropriate regulator of the spray gun. However, the best option in this case would be a general reduction in pressure at the inlet to the spray gun.
The second point that should not be forgotten when setting up a spray gun is the effect of an excess supply of paint on an incorrectly shaped torch. An interesting feature here is the following: in conventional type spray guns, excessive paint supply is expressed in an excessive concentration of material in the central part of the torch trace, while for HVLP and LVLP type spray guns (for example, with Trans-Tech spray technology from DeVILBISS) with excessive supply, the material tries concentrate on the sides of the torch.
The configuration of the torch is critically affected by damage and contamination of the air surface of the material nozzle and the inner surface of the main hole of the air head of the spray gun.
Damage and contamination here give rise to critical deformation of the atomization air jet, which is expressed in the formation of “banana-shaped” and “pear-shaped” profiles.
Test of uniformity of paint distribution in a torch
Turn the air cap of the spray gun or the entire spray gun so that the torch trail becomes horizontal. Place the spray gun at the recommended distance from the surface of the paper or plywood and spray the material until the paint flows downwards under the influence of gravity in the form of streams. Monitoring the relative flow speed of streams and the distance between them helps to make a conclusion about the uniformity or unevenness of the paint distribution in the torch.
In general, for high-quality and effective painting, you need an even distribution of the material or its distribution with a slight accumulation in the central part. However, we must remember that there are air caps that are specially designed to spray material with a high concentration in the center of the spray. Of course, adjusting the spray gun is not the only way to increase productivity and painting efficiency.
In particular, selecting the appropriate type of air cap for the spray gun is very important.
Setting up the spray gun before painting a car with an electric spray gun is regulated by three parameters:
- flame width
- air pressure
- paint supply
With the width of the torch, it is clear that if we are painting an entire car or a part of a car in its entirety, then we need to use the largest width, if the transition is narrow, then we need to reduce the width of the torch.
The paint supply can be kept completely open, because the adjustment screw only limits the travel of the needle, which locks the channel; for this, you don’t have to press the trigger to get the required amount of paint.
conclusions
You can paint a car yourself with an electric spray gun in several cases:
- The quality of the paint is not as important as its cost. This usually happens when repairing an old car or motorcycle. For example, if the old Niva is used as a workhorse in the country.
- It is necessary to touch up small details, perhaps in inconspicuous places.
- The paint layer is applied after straightening work, but then the film will be glued.
- A “liquid rubber” type material is applied to the body.
Read more:
How to choose a spray gun for repainting a car
Design and types of spray guns for water-based paint
Painting the ceiling with a spray gun
Painting plastic car - types of paints, instructions for work
Basic principles of painting a car fender
How to adjust the air supply on a spray gun?
To do this, you need to hang a sheet of thick paper on the wall. Pointing the spray gun at it and holding it at the working distance (recommended by the manufacturer), conduct a paint test, achieving a uniform spray by adjusting the air supply. Smoothly increasing the air supply, occasionally “puffing” the paper, we find the best option. If the paint does not break, you need to add air; if the torch configuration on the paper is in the shape of a figure eight, then this is excessive pressure. We need to find the average pressure at which the torch will be stretched.
We must remember that not only the adjustment of the spray gun, but also the accuracy of the preparation of paintwork materials is of considerable importance. And to do this, you need to read the technical data sheets of the material and follow the preparation proportions (control the viscosity).
What are the benefits of pneumatic spray guns?
Unlike household electric sprayers, pneumatic models use compressed air from a receiver, pumped into it by a powerful electric compressor. The operating principle of both types of devices is almost the same, but there are a number of differences in technical solutions.
In electric spray guns, air is pumped by a turbine and supplied directly to the hose. The turbines used in portable spray guns are not able to create high operating air pressure. Hence all the disadvantages of devices with direct air supply.
Pneumatic units first pump air into a receiver, which creates a pressure of more than 8 bar. High air pressure allows paint to be sprayed into a mist. This is the main advantage of professional painting systems.
On a note
The size of a spray gun drop depends not only on the air pressure created, but also on the degree of pigment grinding, i.e. on the characteristics of the paint itself, regardless of its consistency.
Another advantage of pneumatics is high safety. If an electric wire is suitable for portable spray guns, then in pneumatic installations the entire electrical part is located separately, and a long hose is connected to the spray gun.
The length of the supply hose can be as long as desired (within reason). This allows you to move freely around the part. At the same time, in the spray zone of the paint torch there are no electrical devices capable of generating a spark.
Did you know that...
...fire safety is a very important point when working in a paint booth. All automobile paints are produced on the basis of organic solvents, which are highly flammable substances. When spraying paint, the air in the work area is saturated with fumes, which can ignite from the slightest spark.
