Question 1

What are the Types of Spray Guns?

Accepted Answer

1. Classification by basic use

(1) Make-up spray gun
Spray gun make-up is a very popular technology of make-up, mainly using the spray gun to make-up and a small spray gun through a certain air flow to make the cosmetics more extreme attached to the skin, so as to create a uniform and bright feeling.
(2) Paint spray gun
The pressure spray gun coating is mainly supplied by another booster tank. This advantage is increasing the pressure of the booster tank, facilitating the supply of coating to several spray guns at the same time, which is more convenient and practical. The pressure difference generated at the nozzle of the spray gun will push the paint out of the tank, thus atomizing to form certain particles for spraying, and the coating can be more closely attached to the surface of the object to be coated.
What are the types of spray guns? Different types have different functions!

2. Classification by ways of coating supply mode

(1) Gravity spray gun
The coating tank of this kind of spray gun is located at the upper part of the spray gun. The negative pressure principle is used to mix and atomize the coating and air to adhere to the surface of the coated object.
(2) Suction spray gun
The coating tank of this kind of spray gun is located at the lower part of the spray gun, and the spray nozzle of the coating generally protrudes forward more than the central hole of the air cap, so compressed air is required to make it spray out from the spray nozzle around. Let it form a certain negative pressure in the front end of the coating nozzle to suck the coating out of the coating tank and atomize it.
(3) Pressure spray gun
This kind of paint spray gun is mainly used for painting. After spraying the air cap at the front of the spray gun under pressure, a low pressure area is formed, which is lower than atmospheric pressure.

3. Classification by ways of work

(1) Conventional air spray gun
This kind of traditional air spraying can bring the best atomization effect, so many people still like to use this kind of spray gun, especially the adjustment of the spray gun can be very flexible.
(2) Airless spray gun
This kind of spray gun is widely used in the spraying of metal, wood plastic, ceramics and other substrate surfaces because of its advantages of non-rebound coating and high coating efficiency.

(3) LVMP spray gun
The advantages of HVLP spray gun are better atomization effect, faster transmission efficiency and less air consumption than the ordinary spray gun.
(4) Air-assisted airless spray gun
In a certain field, air-assisted airless spraying technology is more and more popular. It can form a thicker film, and the spraying effect is excellent. Compared with traditional air spraying, it can save 30% coating and has lower overspray, less atomization effect.

These are the different types of spray guns. According to our different needs, different working methods, coating supply methods and basic uses, we can choose the right spray guns, so that our work can be promoted and get twice the result with half the effort.

Question 2

Pneumatic Spray Gun Use and Maintenance Methods

Accepted Answer

The spray gun is a kind of equipment which uses the rapid release of liquid or compressed air as the power. As the most widely used and simple efficiency equipment in modern spraying process, pneumatic spray gun is an indispensable equipment in the whole spraying industry. If you want to play the best function of the spray gun, it’s not enough to just master the operation essentials, and you should also pay attention to the usual maintenance, so how to maintain the pneumatic spray gun? What are the maintenance skills?

Introduction to the use of pneumatic spray gun

1. The spraying distance between the spray gun nozzle and the surface to be coated should be 30-60 cm. If the spraying distance is too close, the coating will disperse poorly and pile up. If the spraying distance is too far, the coating will be too thin and thick, and the flying dust may adhere to the membrane surface.

2. The moving speed of the pneumatic spray gun should be 3-4 m/s. If it is too fast or too slow, uniform coating cannot be obtained.

3. The operation of the spray gun shall be perpendicular to the surface to be coated, so it shall rely on arm action rather than wrist action when spraying, because arm action spraying can achieve the purpose of being equal and vertical, wrist action will produce arc action with wrist as the fulcrum, making spraying uneven.

4. The spraying sequence is usually from left to right, then from right to left, from top to bottom, and then from bottom to top, until the whole spraying surface is finished. At the same time, when spraying, it is necessary to make the spraying surface of the latter stroke overlap the width of the spraying surface of the previous stroke by 1/3~1/2. In order to make the coating film uniform and dense without missing spraying, the spraying thickness is generally controlled by one Chinese character “十”, one and a half “十” or two “十”. Generally, one horizontal and one vertical line sprayed on the entire surface shall be a Chinese character “十”.

Sharing of spray gun maintenance methods

1. Check the sealing book of needle valve, gasket and air valve gasket frequently for leakage. If there is leakage, replace it in time. Oil the sealing gasket frequently to make it soft and easy to slide.

2. The pneumatic spray gun should not be disassembled at any time. Attention must be paid to that rectangular parts should not be filled with garbage and coating, air cap and nozzles must not be any damage, after assembly to adjust to the initial appearance, pull the trigger to test the effect of air and coating spraying.

3. The screw threads of the air cap of the gun, the adjustment knob for the amount of coating discharge and the adjustment knob for the air cap shall be oiled frequently to ensure flexible movement; The spray gun thimble and the spring of the air valve part shall also be coated with oil to prevent rust and facilitate sliding.

4. Before using the pneumatic spray gun, a comprehensive inspection shall be carried out to ensure that the spray gun can be used only when it is in good condition.

5. The pneumatic spray gun shall not collide with the coated objects or fall to the ground during use, otherwise it will cause permanent damage and cannot be used.

6. During the suspension of work, the head of the pneumatic spray gun shall be immersed in the solvent to prevent the coating from drying and blocking the nozzle; However, the entire pneumatic spray gun shall not be completely immersed in the solvent, which will damage the sealing gasket of each part and cause air leakage and coating leakage.

7. The pneumatic spray gun shall be cleaned in time after use, otherwise the coating channel will be blocked (especially 2K coating), and it will be difficult to clean or even unable to use in the future. After cleaning the pneumatic spray gun, connect the coating pipe and compressed air tube for trial spraying, and adjust the fan surface of the pneumatic spray gun. The fan angle of the manual air spray gun is 70-80 degrees. If there is any problem, ask for repair service in time.

Question 3

What is the Difference between Hvlp and Airless Sprayers?

Accepted Answer

In HVLP( "high capacity, low pressure"), the paint is atomized by the air extracted from the air compressor or turbine pump, while in airless sprayers,high pressure and tight extrusion cut the paint into particles, since the piston pressurizes the material from a orifice, which is smaller than the nozzle of HVLP.

The Differences Between HVLP and Airless Spraying Machine

When it comes to difference between hvlp and airless sprayer, airless sprayers are designed for large, relatively flat surfaces, such as walls, tanks, bins, and siding. By comparison, HVLP is suitable for exquisite finish and higher precision required by the contractor, such as handrail, door, cabinet work and window frame.＂HVLP can replace electric brush and airless sprayers the roller.＂　He said. ＂They are actually complementary to each other.＂

The product transfer rate of airless sprayer is only 50%, while HVLP can reach at most 90%. But airless units are more powerful, while HVLP production,not the production of it, is high.

Unlike the airless sprayer,HVLP sprayer has a second control knob for adjusting the air flow, so that the user can better control the of the fan. Due to its less overspray, HVLP is a good choice, when expensive coatings are used.

HVLP finish looks better. Compared with particles pushed by airless sprayer, the atomized particles of HVLP are smaller and more uniform. The difference does not matter when painting dry walls with latex wall paint. But when using HVLP to spray varnish or enamel paint, you can see a finer, smoother surface. Otherwise, the painter may ＂fight＂with the terrible "orange surface", which is a mottled surface texture appearance, rather than a smooth surface.

HVLP paint spray gun is also very convenient for decoration. But airless sprayer units are better for mass work, such as the exterior walls of houses. The airless equipment will finish the loading and unloading of one can of paint at the rate of 0.5-2 gallons per minute, which is much quicker than HVLP, which will do at the rate of 15 or 20 ounce per minute. Speed is a big factor.

Coarse grinding powder, such as flat or enamel emulsion paint, is not suitable for HVLP. They can be brushed, rolled or painted with airless units. The finer the grinding, the more favorable the paint is for spraying.

Turbine HVLP and HVLP connected to the air compressor vary in cost and performance. The turbine works in the opposite way to the vacuum cleaner and is lighter than the compressor model. In addition, their heated air can speed up the drying.It's much easier to just install the turbine unit and plug in.

Question 4

Can you Paint a Car with a HVLP Sprayer?

Accepted Answer

HVLP (High Volume Low Pressure) air spray gun is a new type of spray gun with large flow and low pressure. Its main features are as follows： high painting rate, low cost of paint and less pollution. The painting rate of HVLP spray is 2-3 times of that of air spray. The painting rate of common air spray gun is 30%, wasting 0.7L per liter paint due to flying paint, while that of HVLP spray is 60%, wasting less than 0.4L per liter paint, which helps to reduce the cost of coating and pollution, and improves the environment of the workplace and product quality. The fan surface is even, so it is very easy to get the effect close to the mirror surface when applied to the surface construction of what usually requires high-level decoration, such as the limousines. It is especially suitable for spraying metallic flash paint with obvious, uniform flash effect and good side view effect.

The compressed air pressure is low. Generally, the air pressure measured at the nozzle should not exceed 0.07MPa. With rotary air cap, each gun can be equipped with different air cap, nozzle and thimble to meet the requirements of different occasions. Due to the high painting rate of HVLP system, the nozzle with smaller aperture can be used. HVLP spray gun can be equipped with a variety of air sources, which can be supplied by multiple spray guns in the center, or by a single spray gun independently.

The paint utilization rate of traditional air spray gun is about 30%, with great waste. It not only increases the economic cost, but also seriously pollutes the air and water environment, and damages the health of the construction workers because of the massive emission of VOC, benzene, formaldehyde and other toxic and harmful substances. For the operation that often needs to change the construction point, the air compressor used in the traditional air spraying is large in volume and heavy in weight, and the transportation of equipment will also cause many inconveniences.

Good hvlp spray gun can greatly reduce flying mist and rebound (over spraying), reduce paint and solvent emissions, and greatly improve paint utilization. At the same time, it can keep the working environment clean and the construction personnel healthy. In addition, the electric HVLP spraying machine without bulky air compressor is easy to carry and move, making it convenient to change the construction site frequently.

HVLP spray gun can reduce painting work

One of the biggest benefits of HVLP spray gun is that it can reduce the pain of painting. This is large because they have less "overspray", a phenomenon in which excess paint accumulates on and around the sprayed surface. The HVLP spray gun is applied in a way that avoids the accumulation of this excess coating on the surface.

As a side benefit, reducing overspray means that car paint professionals will need to spend less time to reduce overspray. This process sometimes involves the use of solvents and special tools to remove excess solvents. It takes time and a lot of care.

Saving money on supply and labor is a big advantage of HVLP spray gun. Due to these two reasons, we hope that you use this kind of nozzle in your car painting business.

HVLP spray gun provides better transfer efficiency during car painting

HVLP spray gun not only can better finish the work of painting different car surfaces, but also has better "transfer efficiency". The term refers to the amount of paint sprayed from the spray gun and then stuck to the car surface. The high-pressure delivery system will cause the paint to bounce back from the car, while HVLP spray gun has not so many problems. This difference may be as high as 65% of the transfer efficiency of HVLP and 25% of the transfer efficiency of high-pressure gun.

HVLP paint sprayer for cars will spray less paint into the air, which is more beneficial to your health

When using all kinds of spray guns in automobile spray painting industry, a fine drop of paint will be released, and inhalation of this kind of paint is very harmful to people's health. That's why car paint professionals wear breathing systems when they work on cars. And paint residue in the air means safety is still a concern even after work is done.

Compared with the high-pressure spray gun, the HVLP spray gun sprays less paint into the air, which not only reduces the amount of paint that the face mask needs to clean, but also reduces the amount of paint left behind. In general, this is a great advantage for you and an important reason to use HVLP spray gun. When using HVLP spray guns, keep painting in a well ventilated area and use the respiratory system.

Question 5

How Do you Mix Paint to Spray a Car?

Accepted Answer

Many car repair shops can repaint your vehicle, but a large fee will be charged for this service. If you want to make a beautiful new look for your car, but you don't want to spend more money, then painting by yourself may be a good choice. This will require some knowledge of automotive spray paint gun and mixing methods. However, with the basic knowledge, this smooth new coating will not be too far away.

Get the right supplies

Buy a mixing bucket or cup. It's worth buying containers that are specifically designed to mix car paint. They not only tolerate the re-use of irritating chemicals better, but also have markings, which are valuable when measuring paint.

If you are looking for a quick and cheap option, choose a single-stage coating. Choosing the paint you are going to use is more than just choosing a pleasant color. Different kinds of coatings can accomplish different tasks. The single-stage coating is a coating that can be used independently without additional primer or finishing layer. A good comparison is nail polish. You can apply as many layers as you want, and you don't need any other layers.

It is recommended that a single coating be used for basic colors such as red, blue or yellow. They dry to a smooth surface and are easy to prepare, so they are perfect for novice artists. But please note that these are rarely used to smear the whole car.

If you want more lasting effect, please choose a two-stage painting method. Two-stage or primer/ clearcoat coating will involve at least two coats (one primer, one clearcoat). The primer provides color, while the clear coat provides additional protection against scratches.

The two-stage method tends to produce more metallic luster. If this, as well as better protection, attracts you, then choose a composite coat.

Mix single stage coating

Collect your paint and other required materials. Single stage coatings usually require a mixture of three basic substances. The paint itself will determine the color of the mixture. "Retarding agent" or "diluent" is used to dilute the coating to avoid solid lumps or "orange peel" in the coating.

Hardener will help your paint dry and easy to finish. Pour your material into a mixing container. The technical information of the coating will inform you of the proportion of materials you need, with a series of three numbers. For example, the standard mix ratio for single-stage coatings is 8 / 1 / 1 mixture. That is to say, for every 8 parts of the coating, add one diluent and one hardener.

If you are using a china paint gun cup, there will be a score corresponding to this ratio. Therefore, you can paint the cup to leve' 8'and use diluent to reach'9' and then use hardener to top it to ' 10'. Mix the paint evenly. Paint sticks can be purchased from any shop, any solid wood or old tools will be enough to mix the mixture. Complete thoroughly to create the appropriate consistency. No matter what you use to mix the paint, it will be damaged, so choose something you can't miss. Test paint with spray gun. Add a small amount of paint to the spray gun and leave a disposable surface to test the suitability of the new mixed paint. If the paint does not flow well from the spray gun, add more thinner to increase the flow. If you spray the surface and see that the paint is running, or there is a problem with drying, it indicates that more curing agent is needed.

Mix two-stage coating

Collect different paints and other materials. Primer coating and transparent coating shall be matched with other substances. The primer coating will be paired with a reducer or diluent to ensure best optimum viscosity. Clear coat paint must be used in combination with hardener before it is applied to the car surface. Mix your materials in a mixing container. Please read through the technical information you purchased earlier to determine the proportion of each coating. The ratio of primer coating to reducing agent is always 1/1. Therefore, your container, preferably a mixing bucket, should be semi coated and semi diluent. The clear coat coating will be a little more complicated. Depending on the brand, the ratio of transparent coating to curing agent is usually 4 / 1 or 2 / 1. Mix your compounds thoroughly. Use a paint stick or similar tool and stir the contents until they look smooth. Don't worry about the first complete correct consistency, you will have the opportunity to test the texture before painting the car and further mix if necessary.

Spray the test coating on a safe surface. Put small samples of the two coat layers into the spray gun and apply on the optional items. Wood or old equipment is best. The viscosity of the primer should be checked as this contributes the most to the colour of the vehicle. Although the transparent coating is colorless, it will produce a coveted luster. Both should flow smoothly from the gun.

Question 6

How Do you Spray Paint a Car Step by Step?

Accepted Answer

The process flow of automobile paint is a relatively important link in the process of automobile painting. When we ensure the quality of automobile paint, we should also pay attention to the selection of automobile paint process.

The process of car painting

Clean and dry the whole car.

2. Find out the oil defects of the whole car shell, such as pits, dimples, wavy lines, peeling off, paint falling and rusty parts.

3. The pit requires the sheet metal to be repaired and reshaped with a repair machine. If there are wheel corners, lines and arcs, they should be restored and treated, and then the paint can be applied.

4. It is required to dismantle the obstructions before sheet metal construction.

5. Stick and protect the plastic parts on the body with paper tape. Such as headlights, middle net, decorative strips, glass, etc.

6. Use 60 × paper for the defective parts of the body or put 40 × dry paper on the grinding head of the dry mill, and grind the defective parts into feathery edges.

7. Use a blowgun or wet towel to clean all the return routes.

8. Use a scraper to scratch the sheet metal tools for the first time, and do not scratch too thick each time. Note: only the bare iron part needs to be scratched, and the bare iron part must be covered completely.

9. When scraping and coating the atomic ash, every scraping and coating must be smooth, flat and not too thick. After scraping, bake it with infrared baking lamp. When baking, do not be too close. Keep a certain distance. After drying, polish it with water grinding and dry grinding. The terrazzo is polished with 60 × water paper and special base plate. Dry grinding is to use 40 × sandpaper of dry grinding disc to grind on the dry grinding head at a constant speed. The grinding must be done by hand. Straighten the hand, and repeatedly feel if there is any pit. If there is, a second scraping is necessary.

10. Clean the water and dust on the body surface before the second time of scraping. The second scraping method is the same as above.

11. It is very strict and critical when grinding with atomic ash. To achieve the desired effect, close cooperation between eyes and hands is needed.

12. After all the defects of the car body are filled with atomic ash, carry out strict inspection to ensure that the car body is exactly the same as the original car body before spraying the primer. If any part fails to meet the requirements, the primer cannot be applied. The primer can only be applied after meeting the requirements.

13. When spraying the primer, dry the water on the car body with a blow gun. If the water is not dried, the next step cannot be carried out. Note: water is most likely to accumulate on the body, especially at the sealing strip and anti friction strip. Check carefully before construction to avoid quality problems.

14. Stick and protect, after the previous step is strictly completed. The materials used for sticking and protecting are tape, newspaper and special cover paper. According to the present requirements, generally, 4S stores do not use newspapers, but use special masking paper for strict and standardized sticking and protection. In the process of sticking, the constructors must be careful. The primer construction can be carried out after the completion of sticking and protecting.

15. Spraying primer is the base of spraying the surface, it is necessary to continuously practice shooting skills and techniques. Basic spraying skills: the spray gun must be perpendicular to the car body. When spraying primer, the air pressure should not be too high, generally 3-4pa. The gun shouldn’t move in an arc.

16. After spraying the primer, clean the auto spray gun with banana water and diluent, and put it back to the original position.

17. After the primer is sprayed, remove all the masking paper on the vehicle body. This kind of masking paper cannot be reused. After removal, it will be thrown to the designated place. It is not allowed to place it randomly, which will affect the image and operation of the workshop.

18. The primer shall be dried with red infrared drying lamp and paint baking room, and polished after cooling.

Question 7

Operation of Spray Gun

Accepted Answer

In the process of spraying, improper operation of spray gun will affect the spraying effect of the product. Good spraying effect is shown in: 1. The coating distribution is average. 2. The coating should not be too thick or too thin.

Several problems to be noticed in spraying:

The distance between the spray gun nozzle set and the coating is called the gun distance. The smaller the gun distance is, the greater the spraying pressure is, and the greater the impact of air pressure on the product, the coating will be uneven, resulting in the problem of too thick coating. The larger the gun distance is, the smaller the spraying pressure is, and the coating is easy to lose, so that the coated part of the spray material is too little, and the coating cannot reach the specified thickness.

The spray fan is vertical to the coated surface. When manually operating the spray gun, the spraying width shall not be too large, otherwise, the problem of average coating will occur. The purpose of spray gun operation shall always be parallel to the surface to be coated and vertical to the spray fan. If the operation rate is unstable, the coating thickness will be uneven. If the operation rate is too fast, the coating will be too thin. If the operation rate is too slow, the coating will be too thick.

In a word, when using the spraying equipment, we should make sure that the strength is moderate, and the distance is appropriate, so that we can get the desired coating effect. After the construction, some unfinished things also need to be improved, such as the cleaning of the coating and the help appliances, and the remaining coating materials should be blocked and retained after use. These problems should be paid attention to.

The key points to be paid attention to in the operation of the spray gun include: the moving speed of the spray gun, the control of the trigger, the distance between the guns and the position of holding the gun, etc.

Here is the description:

1. Movement speed of spray gun
In the primer spray gun spraying operation, the moving speed of the spray gun has a great influence on the coating effect.

(1) If the manual spray gun moves too fast, the coating on the surface will be thin and dry with poor leveling and coarseness;
(2) If the moving speed of the manual spray gun is slow, the coating on the surface is sure to be late, and it is easy to produce the phenomenon of sagging.
(3) The best moving speed of the spray gun is that after spraying, the surface coating of the coated object is full, uniform and wet. This needs to be controlled by operators with certain spraying experience.

2. Control of the trigger
The spray gun is controlled by the trigger. The deeper the trigger is pulled, the faster the liquid flows. In the process of traditional gun using, the trigger of electrostatic spraying equipment is always buckled, not half buckled. In order to avoid the accumulation of coating sprayed at the end of using gun, experienced sprayers should loosen the trigger slightly to reduce the coating supply.

3. The orientation of the spray gun to the substrate surface
The spray gun should be vertical to the substrate surface, or as vertical as possible. If the spray gun is a little askew, the result will surely cause the spray band to flow to one side, while the other side will appear dry and thin, lack of coating, which is extremely likely to cause stripe coating.

4. The interval between the spray gun and the surface of the base material
For the siphon spray gun, the optimum working interval is15~20cm. If the interval is too close, it may produce flow, and even cause the color inconsistent with the expected when spraying metallic flash coating or pearlescent coating. If it’s too far apart. More than 20cm, it may lead to dry spraying, over spraying and poor leveling of the coating. If the metallic flash paint is sprayed, the possibility of color change may also exist. The pressure spray gun can be far away from the base material. Generally, the best interval is 20 to 30 cm. These are the principles that must be followed during spraying construction.

5. Holding the gun
The spray gun is held by the palm, thumb, pinky and ring fingers. The middle finger and index finger pull the trigger. Some spray painters change the way of holding the gun from time to time when they work for a long time. Sometimes they only use their thumbs and palms with their little fingers, sometimes they use their ring fingers to hold the gun, and their middle and index fingers are used to pull the trigger. Electrostatic spraying equipment can alleviate fatigue and improve work efficiency.

Question 8

The First Use of An Automatic Spray Gun

Accepted Answer

For the first time, the automatic spray gun is often used to operate new tools. In a period of time when we use it, there will be a certain period to adapt the spray gun. Just like the newly purchased car, there will be a certain period of time for us to adapt to its different performance, and then we will drive more and more smoothly. What will happen to the new automatic spray gun?

1. A new automatic spray gun needs cleaning

When we buy a new batch of automatic spray gun, there is no need to rush to get the paint to spray the trial products. We should clean the inside of the spray guns, because there are some impurities in the new spray guns. Of course, we shouldn’t use clean water directly. We should wash it with thinner or the oily water. It is mainly because these are diluents when adjusting the paint concentration, so they are all feasible cleaning agents.

The main steps of cleaning are the same as that of spraying paint. Put thinner or the oily water in the paint bucket, with pneumatic diaphragm pump and supply it to the automatic spray gun. In this way, open the controller and spray it for about a few minutes.

2. Air pressure required for new automatic spray gun is not enough

When many customers take the spray gun back for testing, how can it not produce oil when it is turned on? It only produces gas. The main reason for this phenomenon is that the air pressure must not be enough. But the customer will say that the air pressure is enough. The air compressor comes out 0.6Mpa. Of course, if the air pressure is always this number, the spray gun can spray. Because the starting air pressure required by most automatic spray guns is 0.3-0.5mpa. So why is there no painting?

The main reason is that the gun needle is not opened, so the reason why it is not opened is the air pressure. To be precise, there is not enough water. We all know that the principle of pneumatic spray gun is to spray the liquid by compressed air atomization. Therefore, the speed of atomization and fan-shaped gas consumption is very large. When our gas storage tank is small, it cannot meet the normal operation of the spray gun at all times. Thus, there will be either no oil or stop after a while.

The solution is to change a larger size of air compressor or increase the size of the air tank, so that the air pressure and air volume of the air supply can be met normally, and the automatic spray gun can be used for spraying normally.

Question 9

Spray Gun Classification

Accepted Answer

According to the spray gun working principles, they can be divided into three categories:

① At the same time, the coating gravity and front vacuum suction gravity are used;

② The suction type of front-end vacuum suction is only used;

③ The coating pump delivers the coating to the pressure type at the front end of the nozzle.

In addition, according to the use of different types of coating, it can also be divided into primer spray gun, finish spray gun and miniature spray gun.

According to the different ways of coating supply, coating nozzle size, air usage amount and spray pattern, they can be divided into three types: suction type, gravity feed spray gun and pressure type.

Suction spray gun: the principle is to use high-speed air flow and make the spray gun partially vacuum, thus generating suction to suck the coating from the pot to the spray nozzle for atomization and spraying, mainly for a large area of spraying, the advantage is that the coating atomization is better, which can meet the thickness and glossiness requirements of the coating film.

The coating tank of the suction type spray gun is located in the lower part of the spray gun. The coating nozzle generally protrudes forward more slightly compared with the central hole of the air cap. Compressed air is ejected from the central hole of the air cap, namely around the coating nozzle, forming a negative pressure at the front end of the coating nozzle,

The coating is sucked out of the coating tank and atomize. The spray rate of the spray gun is obviously affected by the viscosity and density of the coating, and is closely related to the diameter of the coating nozzle. The suction spray gun is suitable for general discontinuous spraying operation.

Gravity feed spray gun: use gravity to lead the coating from the upper pot to the lower nozzle, and then spray it with the wind. The previous design is for small area repair, and now it has developed to full-scale spraying. The advantage is that the coating can be saved in small area repair.

The coating tank of the gravity feed spray gun is located at the upper part of the spray gun. The coating is ejected from the coating nozzle by its own gravity and the negative pressure formed at the front end of the coating nozzle and mixed with air for atomization. The basic structure of the spray gun is the same as that of the suction spray gun, but under the same spraying conditions, the spraying amount of the coating is larger than that of the suction spray gun.

The gravity feed spray gun is used in the spraying operation with less coating consumption and frequent color change. When there is a large amount of coating, a high-level coating tank can be set up to connect the spray gun with the hose. In this case, the spraying amount of the coating can be adjusted by changing the height of the coating tank.

Pressure spray gun: the pressure spray gun supplies coating from another coating booster tank (or coating pump), which can supply coating to several spray guns at the same time by increasing the pressure of the booster tank. The coating nozzle of the spray gun is located in the same plane with the central hole of the air cap, or is slightly concave compared with the central hole of the air cap, so there is no need to form negative pressure at the front end of the coating nozzle. The pressure spray gun is suitable for the continuous spraying with a large amount of coating.

Internal mixing spray gun: there are two air supply systems in the body of the internal mixed spray gun, i.e. the compressed air system used for mixing and atomizing the coating and the compressed air system for pressurizing coating in the coating container. The coating supply mode is the pressure type. The center hole of the air cap is long olive shaped, so the spray pattern is elliptical. The spray gun has no side air holes and auxiliary air holes and cannot adjust the spray pattern arbitrarily. The spray pattern is determined by the shape of the center hole of the air cap. To change the width of the spray pattern, the air cap must be replaced. Therefore, the internal mixing spray gun has no spray pattern adjustment mechanism, and the other adjustment mechanism is similar to the external mixing type spray gun.

Question 10

How to Choose Paint Spray Gun?

Accepted Answer

Paint spray gun

Paint spray gun -- just as the name suggests, "Spray" means the way it works, "paint" means the material for spraying. As a tool for spraying paint, it is a kind of coating equipment, used for surface treatment of products. The paint is atomized by compressed air into small paint drops, which is sprayed to the surface of the coated object under the driving of air flow. It is mainly composed of spray, nozzle, needle valve and gun shell, and meanwhile, connected to external air pressure device, such as pressure tank, pressure barrel, pump, etc. Compared with the traditional manual painting, the spray gun is more time-effective, more beautiful, 5-10 times higher in efficiency, with the coating being fine, smooth and even.

Selection of spray gun

In the selection of spray gun, in addition to the working conditions, the size and weight of the spray gun itself, the way of coating supply and the diameter of the coating nozzle should be considered.

(1) The size and weight of the gun itself. In consideration of reducing the labor intensity of the operator, small size is better, but the spray gun with small gun body also has adverse factors, such as small spraying amount and air amount, which slows down the operation speed of the spray gun, increases the spraying times, and reduces the operation efficiency, so it is not suitable for large-scale coating. However, when using large spray gun to spray small parts or tubular coating, the coating loss increases. Therefore, the large spray gun can be used for the flat large-scale coating, and the small spray gun is suitable for the coating with very different unevenness

(2) Coating dosage and supply mode. When spraying flat coating, due to small amount of paint and frequent color change, small gravity spray gun is recommended. However, it is not suitable for back-surface coating, since the amount of coating is a little larger, and color change is more frequent, especially when spraying the sides, it is better to use a suction type spray gun with a can less than 1 liter. However, when spraying the flat coating, the suction spray gun is not applicable. If it is a continuous operation with a large amount of paint and rare color change, the pressure feed type can be used with a paint booster tank with a capacity of 10-100 L, or when the amount of paint is larger, the pump and paint circulation pipeline are used to press the paint. The pressure spray gun, light in weight, does not have a cup or tank, and it is convenient to spray up and down, left and right. The disadvantage is that the cleaning work is more complex than the gravity type and suction type. The balance between the paint pressure and air pressure should have certain technology, but it is easy to master after being proficient.

(3) Nozzle diameter. The larger the spray gun nozzle set diameter is, the larger the spraying amount of coating will be, and the higher the viscosity of coating will be, the less the spraying amount of coating will be. Therefore, the spray gun with large nozzle diameter should be selected for the coating with high viscosity. The spraying amount of the pressure spray gun will increase with the increase of the pressure, so the pressure spray gun with small nozzle diameter can also be selected. When the appearance requirements of spraying primer are not high, and the coating film is required to be thick, the spray gun with large nozzle diameter can be selected; when there is a high requirement for atomization in spraying the finish paint, the smaller nozzle can be selected. When spraying the primer, if the low viscosity coating is used, the nozzle with smaller diameter can be selected.

Question 11

How to Choose the Appropriate Industrial Spray Gun？

Accepted Answer

There are four factors that should be considered when choosing the appropriate industrial gun: application, accessories, and price.

The object that will be sprayed determines the choosing of the type of spray gun and the size of the nozzle. For example, a large object needs the spray gun with big-size nozzle to ensure efficient work.
High-quality and appropriate spray gun accessories need to be considered due to some special requirements in some industrial fields. Accessories can help the industrial spray gun perform well.
Compare different industrial spray guns meet your needs within your budget, and find out the optimal type and purchase at the optimal price.

Question 12

How to Choose Car Paint Spray Gun for your Needs?

Accepted Answer

When you're repainting your car or you want to give your car a fresh coat, you’ll need a car paint spray gun. Considering the final effect appears in your car, you need to choose the right type of car paint spray gun and then use it in a proper way.

Make sure how often you are likely to use the car paint spray gun.
Choose a car paint spray gun with gravity feed since less air enters the paint and saving paint can be achieved.
Choose the right size of the tip of the car paint spray gun for your need. Check the details of the parameter or consult the supplier professional suggestions.
Choose a car paint spray gun that doesn't need much air pressure.
You can also choose a car paint spray gun with high working speed so that you can get the work done efficiently.

Question 13

What are the Parts of the Industrial Spray Gun?

Accepted Answer

An industrial spray gun consists of basic parts of aircap, flow regulator, nozzle, and tank (some types of industrial spray gun have a tank).

Aircap: this part works for mixing the air and paint, directly affecting the quality of the result and amount of the paint used.
Flow regulator: this part is used for adjusting the amount of paint coming out through the nozzle.
Nozzle: this part is where the paint comes out. Different sizes of nozzles are available to choose according to needs, and some industrial spray guns have interchangeable nozzles.

Spray Gun Accessories