How to choose the best spray gun without the help of a consultant? First, you need to understand the basic characteristics of the tool and determine the planned frequency of use.
For a rare car paint job, there is no point in an expensive spray gun. Here, an inexpensive model with an HVLP spray system will also cope.
Another thing, if you are going to paint seriously – here you need to think carefully.
Spray gun systems- HP, HVLP or LVLP
You should start by choosing a spray system. Currently, there are the following variants of paint sprayers:
Each technology has both advantages and disadvantages.
HP paint guns have long been the only tool for painting in auto repair shops.
They consume a relatively small amount of air and operate at an inlet pressure of only 3-4 atmospheres.
The absence of the need for a productive and expensive compressor is a clear advantage, but what about the disadvantages?
The main thing to remember is that the “HP” spray system allows you to transfer from 30 to 45 % of the paint to the product.
Everything else (about 55-70%) goes into the paint mist, which does not fall on the surface of the paint.
HVLP paint sprayers are superior to their predecessors (HP) in efficiency at the cost of more air consumption, and therefore a more productive and expensive compressor.
Most often, models require an inlet pressure of 2-4. 5 atmospheres, and spraying takes place with a pressure of up to 0.7 atm.
The low output rate contributes to a greater transfer of paint and varnish materials-65-70%.
An important feature of using “HVLP” tools is the need to apply paint at a distance of 10-15 cm, which requires a well – “stuffed hand”.
The HVLP spray system is a modification of the HVLP in order to reduce the amount of air consumed.
High performance, the percentage of paint transfer-65-70% and not such serious requirements as those of HVLP paint sprayers make such a tool a desirable purchase for many craftsmen.
Like HVLP, it is perfect for painting a car, both periodically and permanently. LVMP is most often recommended for finishing work.
LVLP or HTE pulverizers are the leaders in the amount of paint transferred to the surface to be painted – from 70% and above.
The minimum losses are achieved by technological features. The instruments use an inlet pressure of 1.6-2 atm and spray at 0.7-1.2 atm. Due to this, it was possible to obtain a smaller spray torch than that of HVLP spray guns, but at the same time reduce the amount of air consumed.
This type of gun is great for applying any paint materials, but it also has disadvantages.
A smaller torch and a lower spray speed all reduce the speed of operation, which may not be acceptable when the tool is constantly used, for example, in a car service station.
What to choose? Someone will decide that HP is not suitable at all, and LVLP is best. But don’t jump to conclusions.
HP paint sprayers are most often purchased because of the low cost.
Many choose them under the condition of using inexpensive equipment, low compressor costs and cheap paint and varnish materials.
In this case, the extra paint consumption can be compensated by other savings.
As mentioned earlier, LVLP spray guns are more economical in terms of paint consumption, but they leave their mark on the speed of operation, which is not very profitable for large volumes.
HVLP and LVMP systems – something average and optimal:
They are chosen both for one-time (periodic) work and for permanent use for professional purposes.
How to choose the right nozzle size
For absolute beginners in the use of pneumatic paint sprayers, we explain that the nozzle is the most important element of the tool that forms the spray torch.
The part has holes with different diameters to adjust to the viscosity of different materials.
There are certain recommendations for choosing:
- 2 mm-suitable for a local painting
- 3-1.6 mm-solution for base, varnish, water-soluble paints
- 4-1.7 mm-for varnish and acrylic
- 6-2.2 mm-for priming
- 5-3 mm-spray liquid putty
Let’s pay attention to the fact that many masters choose one optimal size and after getting a certain experience; they use it with different types of materials.
The exception is the primer and putty, which need a large diameter of the nozzle.
The nozzle can be monolithic and replaceable. The second option is preferable for those who are going to use the spray gun for several types of work.
What should be the tank of the spray gun?
The spray system and the size of the nozzle are undoubtedly the basis for choice.
But the differences between modern models of spray guns do not end there. A lot of questions are raised by the choice of a tank for the tool.
Let’s start with the location. Where should the tank be located for convenient operation? Here everything is individual:
The tank is at the bottom: When the lower position of the spray gun is freely placed on the surface, and the container itself for paint and varnish materials does not interfere with the visibility of the master.
The tank is on top: Even once in front of your eyes, the top tank will not be a hindrance for some, while others will consider this feature a significant disadvantage.
A special feature of this type is the complete consumption of paint-without any residue.
The tank on the side: Among the premium segment, you can also find such models.
Most often, the tank is not just on the side, but the tool provides for the possibility of installing the tank in any position. The design eliminates any loss in spray quality.
The volume of the tank is selected depending on individual preferences – the larger, the longer you can work, but the tool becomes heavier. Again, you should choose something that will allow you to work more comfortably.
The material of the tank: There are a few important points here:
Plastic barrels of the spray gun weighs less and load the master. They clearly show the remnants of paint. They are perfect for water-based and acrylic paints. Therefore, they are chosen most often.
Metal barrels of the spray gun is selected as necessary. When using solvent-based paint materials, the master simply has no other choice.
Consider all of the above and for sure choose the best tank option for your needs.
One, two or three – how many spray guns to use
Currently, there are models of spray guns recommended for various purposes. Many masters get a separate tool for the base, applying varnish or primer. Of course, this is convenient, but not necessarily.
There are many examples of craftsmen who use one spray gun for many types of work. However, here you will need to develop the skill for high-quality use of the spray gun.
Which compressor is suitable for a spray gun?
Experts advise you to choose a compressor for the tool and not vice versa.
Exceptions can only be made if you buy ready-made kits, for example, the FUBAG MASTER KIT compressor with a whole set of tools.
If you need to choose the best option for your spray gun you should follow several important rules:
- The output capacity of the compressor (!) must exceed the average airflow rate of the spray gun by at least 20%.
- The compressor pressure must exceed the maximum operating pressure of the paint sprayer by 2 atm.
- For an ordinary master, the volume of the receiver 24-50 is quite enough.
We have listed the generalized recommendations. If you want to accurately calculate the necessary parameters for a specific tool, use our article “How to choose an air compressor for a garage”. It contains all the necessary formulas and calculations.
Practical tips for using a spray gun
Having decided on which spray gun to choose for painting a car, you can safely take and use the tool.
But how to set it up correctly? How do I test the paint sprayer to eliminate the possibility of problems? In addition to the above material, we decided to add some practical tips.
How to set up a spray gun for painting cars
Before you start working, you should correctly set the necessary adjustments. The following functional parts can be used for this purpose:
- Air supply regulator
- Paint supply regulator
- The controller shape of the flame
- Air pressure regulator (optional or compressor setting is used))
Of course, there are no universal instructions for adjustment. Each master adjusts the tool to suit himself, ensuring maximum efficiency.
The main thing is to understand in time when to fix the setting. And there are key pointers here.
For air supply:
- The excessive air supply can be determined by dry paintwork and over-dusting.
- If there is a lack of air, visible drops will appear, due to poor splitting of the paintwork.
Experienced craftsmen regulate the air supply through the pressure regulator, which is installed at the junction of the hose and the spray gun.
This allows you to set more accurate values and remember the optimal modes.
If there is no adjustment adapter, you can use the compressor pressure regulator.
However, this will be more difficult, because for every meter of the hose there is an additional pressure reduction.
And one more important point. To adjust the pressure, the paint supply and the torch regulator are often completely unscrewed. And the pressure itself is tested during a test spray, which we will talk about later.
For the paint supply:
A weak supply will significantly slow down the working process, which is unacceptable in conditions of a large volume of work, for example, in a car service station.
The reverse value can cause a lack of air and cause a lot of problems.
Together with the feed rate of paint to increase the flow of air. This will speed up the process, but do not forget that you will have to move much faster if you want to get a uniform coating.
What do experienced craftsmen do? Specialists often twist the regulator to the maximum and adjust the speed of their own movements.
And this is clear because they need to cope with the task as quickly as possible.
Note that in addition to this, they also slightly divert the spray gun from the surface.
With proper skill, this will allow you to effectively apply paint and varnish materials without smudges.
For the torch shape:
- A small torch guarantees an overly saturated spray that is sure to cause drips. To prevent this, usually reduce the speed of the paint supply.
- The larger the torch, the faster the work, and the application is more uniform.
The torch setting is selected based on the tasks performed. Please note that on many spray guns, you can change the angle of the torch.
Setting up the spray gun experimentally
Prepare the masking paper and adjust the spray gun according to the following recommendations:
- Set the pressure on the regulator when the trigger is pressed in accordance with the manufacturer’s recommendations (if you are a beginner, then any in the available range).
- Using the torch control, expand it to the maximum value (unscrew it completely), and then reduce it slightly.
- Fully tighten the regulator of the paint. Then use it to set the desired value. For the fitting, we recommend making 2 full turns of the regulator.
Electric spray guns for a car painting
The electric spray gun is a fairly new device on the market. This is a fully balanced, often automatic complex.
For it to work, you only need access to the power supply network. All the necessary equipment (compressor, spray handle, colorful glass) is assembled in fairly compact units.
Until recently, the main drawback of the electric spray gun was called a large mass and a small convenience of operation.
But today, models are produced that do not cause almost any inconvenience.
An ideal option for a beginner is an electric spray gun, the compressor unit of which is hung on the backpack straps-unloading behind the operator’s back (or on the shoulder).
The modern electric spray gun offers a number of convenient features:
- long continuous operation thanks to the use of a diaphragm compressor;
- high-performance models with a reciprocating compressor;
- high overall reliability and durability;
- a variety of the range of used paints, lacquers, primers;
- High productivity of work.
In addition, the electric spray gun allows you to not fully use the working mixture and quickly change the containers.
You need to choose such a device based on the nozzle diameter, available adjustments, and the nature of paint consumption.
In general, the tool of this class does not offer high flexibility and versatility, but it allows you to perform the necessary operations with the help of a single device without complex settings.
How many spray guns do you need to have?
Many awtomalar buy multiple guns for different materials and purposes.
There are sprayers recommended for the base, primer or varnish. The ideal option is when you can afford three guns.
In this case, you will not have any problems with getting paint particles into the varnish that was sprayed before.
To purchase three spray guns, of course, is not necessary. Many awtomalar having one spray gun with a 1.6 nozzle put all the materials from the paint to the primer.
This requires more effort and time to clean the tool well after spraying different materials.
Be sure to pay attention to the parameters that are suitable for your compressor when choosing a spray gun.
Or after buying a spray gun, choose a compressor for the gun. The main parameter of the compressor is the supply of a certain volume of material at constant pressure, during the use of the tool.
There is a basic rule of good compressor performance: it should produce 2 times more cubic units per minute than the spray gun needs at a given pressure.
If the compressor performance is not sufficient, you will not get a good spray, then the compressor will give out an insufficient amount of air.
Hoses and fittings are also important when choosing a spray gun. When using a 1/4-inch diameter hose, the normal air passage will not be possible.
Choose a good hose with a diameter of 3/8 and built-in fittings with a good transmission effect. These preparations significantly improve the passage of air in the hose.
Tutorial for beginners: how to paint a car with your own hands
It is better to paint the car in a well-lit place if this happens in the garage – the car should not be showered with dust, cobwebs, dirt. The stages of preparation for painting look like this.
- The housing is thoroughly washed, all dust, traces of bitumen, grease are removed. Only use special solvents or White Spirit.
- Bumpers, lighting equipment, decorative elements, wheel protection in the arches and other parts that are not subject to paint are dismantled.
- The condition of the coating is being studied. All defects (chips, cracks) are marked with chalk or acrylic paint.
- In the marked areas of paint with a screwdriver to break the metal region trimmed by sandpaper with grain size 60-80, ensuring a smooth transition to the undamaged paint surface.
- The defective areas are putty-filled. To do this, a finishing mixture is used, it must be smoothed, achieving a flat surface, as little as possible protruding above the undamaged paint.
- After the putty dries (according to the manufacturer’s instructions), it is sanded with skins from 120 to 600, perfectly aligning the defect area with the surface of the undamaged paint.
Important! At the final stage of sanding, in case of the excessive zeal of the performer, it may be necessary to apply an additional layer of putty to level the surface.
Before painting, you should protect all unnecessary areas with masking tape, newspapers or film.
The entire surface of the body is evenly sanded with grain 1200 to a matte finish. After that, dust is cleaned, wiped with White Spirit, followed by drying. The car is ready for painting.
Popular breakdowns and repair methods
Most likely, the reason is not a factory defect, but the inexperience of the user.
Try to adjust the device using the adjusting screw. Attach a small sheet of watman to the wall and try to improvise with the paint, gradually opening the screw.
Adjust the feed of the paintwork without squeezing the trigger of the gun.
The screw creates barriers to the movement of the needle, does not allow it to open the exit hole for the paint composition.
If the adjustment of the pressure supply has not changed the situation, you need to check whether the needle is dirty.
Try to clean the needle and nozzle, repeat the test on the watman. If the reason is a damaged grid, you need to change it.
Sometimes the spray gun refuses to work when the outlet opening for the paint composition is fully opened.
This may mean that you may be using an excessively viscous substance.
If large lumps are visible in the mass, rub the paint composition, and then strain on a vibrating screen.
Try to apply the paint to the watman already in a new consistency, adjusting the pressure with a screw.
Also, check the condition of the air supply. After pouring the paint into the tank and connecting it to the airline, gradually add air pressure. Do in parallel with the increase in pressure, periodic short “pryski” on the watman.
Carefully read all instructions for the storage and prevention of the device of a particular brand. Try to wash all the specified elements of the device immediately after work. Use the materials recommended by the manufacturer of your spray gun.
Construction and painting tools are gradually being improved. The usual brush and roller push back the spray gun, which allows you to evenly paint large areas in a short time.
The device is easy to use, but, like any technique, sometimes fails, ceases to perform its functions.
What should I do if the spray gun does not spray the paint properly? Why, instead of a uniform discharge of paint, do “spits” fly out of the nozzle or just air blows?
Adjust the size of the torch in the spray gun
First of all, you should adjust the optimal width of the spray gun torch. This depends directly on the surface area to be painted. If the car or part is completely covered with paint, the maximum width is set.
When processing a small area, the width of the torch is chosen small, having previously tested the quality of the spray on the watman.
This will allow you to apply the paint evenly and quickly. It must be remembered that by reducing the width of the torch, you need to simultaneously reduce the air pressure.
Accessories involved in painting
The modern industry produces special devices for the procedure of painting equipment.
The use of a spray gun and an airbrush provides an opportunity for motorists to transform the vehicle with their own hands so that the result of the efforts made is no worse than that of professionals.
The appropriate equipment is selected in accordance with the planned scope of work, i.e. it all depends on what you want to paint: the entire surface of the body or only a separate element of it.
The device of the universal spectrum of action is just a paint sprayer, the shape of which is very similar to a gun.
Table of paint consumption when painting a car with a spray gun
When painting, a very important skill is the ability to adjust the pressure. The outcome of all work will depend on how well the pressure regulator is set up.
In order not to waste money and save personal time, you should understand this issue thoroughly; take into account the recommendations of those who specialize in this issue.
Painting a car with an illiterate chosen pressure threatens to turn into a defective paint application. At the same time, they note:
The high pressure causes overspending of paint, streaks, spoiled work in general, which will have to be done again.
Too low pressure also affects the quality of the coating, in addition, it requires the use of a highly powerful compressor.
Adjust the air pressure
Choosing the optimal pressure supply is not easy. There are many parameters on which it depends: the model of the spray gun, the type of paint, the viscosity index.
On the vatman, from a distance of 25-30 cm in a horizontal position, several test bursts are made with simultaneous adjustment of the air pressure. Then the resulting prints are carefully examined:
- drops with streaks, large-the pressure is insufficient;
- the shape of the eight indicates that the pressure is too high;
- a print in the shape of a pear, banana, or crescent indicates a malfunction of the device or a clogged nozzle or airhead;
- The ideal shape is an elongated beautiful torch without streaks and drops.
Depending on the model of the device, the pressure regulator can be integrated into the handle or have a removable design.
If the regulator is removable, it opens at the connection point of the hose to the receiver.
If the regulator is built-in, the pressure is changed when the trigger is pressed.
Adjusting the air supply on the spray gun
Proper adjustment of the device involves several procedures:
- preparation of the coloring composition;
- setting the desired dosage of the paint supply (if necessary);
- regulation of the flow of air.
- The third point is more labor-intensive.
Begin to adjust the paint pressure after all the preliminary work with the coloring composition.
For experiments, you will need a sheet of watman or paper in A3 format and higher. It is fixed on the wall.
All this will be required solely for the implementation of the adjustment and will not be required during further work.
After that, the prepared coloring liquid is poured into the spray gun and pre-sprayed on a sheet of watman pinned to the wall.
The pressure settings are adjusted until the experimental surface is evenly covered with a thin layer and there are no streaks on it.
It is very difficult to find the ideal pressure without preliminary tests since the required value is selected from a number of parameters: the grade of the coloring composition, its viscosity, modification of the spray gun.
Therefore, the installation of the required pressure is carried out precisely by sampling-by equidistant air supply and evaluation of the covered surfaces.
When there is no release of paint in the form of fine dust, but at the same time drops of different gradations fall on the sheet of the watman, it makes sense to add air.
When the shape of the torch takes the shape of an eight on the surface, it signals an oversupply of air supply and increased pressure.
What parameters regulate the operation of the spray gun?
All modern varieties of pneumatic spray guns have three parameters that regulate the operation:
The following parameters depend on the value of the parameters: productivity, transfer coefficient, fineness of material spraying, uniformity of application.
Setting up the paint feed
After the torch width and air pressure are set, adjust the paint supply.
The adjustment screw, twisted to the stop, is released for 2 turns. When adjusting, it is not recommended to give a large feed, it is better to do it gradually during operation.
Otherwise, you can waste a lot of paint and spoil the surface of the car.
The adjusting screw acts as a stop for the needle, which partially covers the paint inlet.
Thus, it is convenient for the master to adjust the paint supply by opening the screw and pulling the trigger.
Operate with only the force of pressure on the trigger.
What is a pneumatic spray gun?
Explaining the essence of the device in a nutshell, a pneumatic spray gun can be described as a paint gun that operates on air pressure.
Delving into the details, you can see that this device can be of different shapes and sizes.
In addition to models of ordinary dimensions, you can find miniature spray guns with slightly reduced performance, but not the advantages that a pneumatic spray gun has.
The upper tank contributes to the natural supply of paint, due to the force of attraction, but the pistols with the lower location work on the principle of discharge, displacing the paintwork from the tank with air pressure.
On some devices, mainly of a miniature size, the tank can be located on the side in the upward direction and rotate 360°, ensuring the operation of the spray gun in any position.
There are also vacuum tanks, which are a structure made of a rigid frame with a lower hole and a soft container that contracts as the liquid is sucked and sprayed. This type of tank, as well, allows you to use the tool in all positions.