Paints in powder form are distinguished by the creation of a particularly durable and stable coating. But in order to distribute it over the surface, you need to work using special technology. Powder painting equipment is required. The features of the process and the rules for choosing a gun and other devices for painting will be discussed in detail below.
Advantages and disadvantages of powder coating
The demand for powder compositions for painting work is the creation of a durable coating that can withstand negative environmental factors and last a long time. At the same time, painting material is saved, and the product is environmentally friendly. This is due to the fact that the composition does not contain harmful substances, such as thinners, and consumption is also slow. Particles of powder that fall off during painting can be collected and reused.
The following advantages of this material can be highlighted:
- There is no untidy smell;
- The dry composition does not have the property of spontaneous combustion;
- If you don’t like the result, the layer can be repainted without difficulty;
- You need to apply one layer;
- The composition is distributed evenly over the base;
- No priming required;
- They do not rust and withstand changes in temperature.
The technical process also has some disadvantages:
- Not suitable for wood and plastic;
- To coat large items, a large drying oven is needed;
- It is difficult to create a thin coating;
- High price.
There are no harmful substances such as thinners in the composition, and consumption is also slow.
Equipment
According to the operating principles, equipment is usually divided into several types:
- Electrostatic. Allows you to obtain ultra-thin coatings - in the range of 30-250 microns. Also, using electrostatic devices, you can process parts of any shape. The equipment is not labor-intensive and economical to maintain. If desired, changing the paint will not take much time. It is also worth noting that there is no need to preheat the products. The main disadvantage of electrostatic devices is their high cost.
- Tribostatic. Systems of this type operate without a particle generator. During the spraying process, a charge is formed due to the friction of particles of paint and varnish material against each other. A significant disadvantage of tribostatic devices is the difficulty in providing sufficient charge, which is why adjustment of the primary paint is often necessary. It should also be noted that the quality of charging depends on the level of humidity, the rapid decrease in charge during operation and the not very active deposition of powder.
- Fluidized. Equipment of this type is designed for layer-by-layer application of paint. This approach ensures sufficient layer thickness (approximately 250 microns). Moreover, the technology allows you to largely control the thickness of the spraying. In addition, preparatory work and further operation of the coating are inexpensive. The disadvantages of fluidized equipment include: increased paint consumption, the requirement for preheating and drying of the part, and the requirement for a simple shape of the surface to be treated. In addition, the metal must be resistant to high temperatures.
Advice! Powder paints, although not classified as substances that require increased safety measures, still contain some dangerous substances. These include lead, cadmium, triglycylisocyanurate hardener, allergens, epoxy resins. Therefore, before working with powder formulations, you should protect your respiratory system.
Methods of working with powder paint
Powder painting equipment can be used in different ways. So there are several ways to apply an unusual coloring composition to a surface. The following work options can be distinguished:
- Typically, the electrostatic application technique is used; in a special apparatus, the powder particles are charged, and the base that will be painted remains neutral. This is how an electric field is generated so that the particles attach to the surface and a reliable adhesion is created. Then the object should be heated to 200 degrees in a special oven; under the high-temperature influence, the top layer of the base melts, and the paint is reliably absorbed into it. The charge gradually disappears;
- The second option begins with heating the base until the powder particles are transferred to the metal. Their contact with a heated surface leads to melting, sometimes it is necessary to reheat the base. This depends on the paint chosen;
- Another method is used for thermoplastic paints. Powder coating equipment that contains a propane burning chamber. Powder particles are heated in advance and released onto the base, clinging securely to it. The method is considered new, for this reason it is rarely used.
The first method is more common since there are different types of powder painting equipment, and they can be used at home. For the second method, you need to set the heating temperature correctly, the third is still little known.
Powder painting equipment can be used in different ways.
Types of dry paints
Dry paints contain various pigments, resins, fillers and other additives.
Powdered dyes are now used in many areas, and their number is growing as the industry rapidly develops. Powder paints can be divided into two groups - thermosetting and thermoplastic.
The former includes a thermosetting film former. During painting, a uniform layer is formed during chemical reactions and melting of its particles.
This group includes epoxy paint, polyurethane and polyester, which contains resin.
Polyester dyes are good for painting items in the yard of a house, for example, for a playground, since weather conditions do not affect it in any way, the paint holds well.
Epoxy enamels are also very resistant, do not dissolve, but can turn yellow if the painted product is overheated.
Due to excess ultraviolet radiation, the topmost layer of such paint is destroyed. But polyester-epoxy paint does not turn yellow from excess heat and light, although they have a similar composition and can withstand higher degrees.
Acrylate dry paint is needed for objects that are actively used. It can withstand alkalis and high temperatures, and is also durable and retains its brightness for a long time.
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Polyurethane powder dye has a shine. It is best used on items that are subject to wear and tear and are constantly subject to friction to protect and preserve them.
And the dye also has an attractive feature - it can be used to create the effect of compressed silk, which looks good in the interior.
This paint is waterproof and does not react to solvents, liquid fuels and various mineral oils.
Thermoplastic dyes are more natural, but less durable. Most often they are used for installation inside and outside the house, as well as for painting various products and objects to protect them from damage and corrosion.
This paint is sometimes used to paint interior items and even parts of washing machines and dishwashers to prevent the action of detergent.
Criterias of choice
An important step is the selection of a dye; the construction market offers a large number of options from various manufacturers; the chosen paint determines the quality that will be obtained after painting.
The following criteria must be taken into account when choosing:
- Resistance to mechanical stress;
- Temperature resistance, the layer must withstand high temperatures and heating processes;
- Electrical insulating characteristics, often polymer-based products are considered dielectrics, and they are used as a protective layer against electrical influences;
- Resistant to chemicals if detergents, gasoline, etc. are used on the metal base. facilities;
- Resistant to corrosion, so exposure to chemicals and water is required.
There may be other differences in the appearance of the coating:
- A smooth layer is created by most compositions;
- Textured, you can get different textures, an example is orange peel;
- Colorless, used to protect the base;
- Tinted, with their help you can create the effect of a different material - bronze, metal, etc.;
- Coatings of different gloss levels, glossy or semi-gloss, etc.
An important step is the selection of a dye; the construction market offers a large number of options from various manufacturers.
Electrostatic spray gun
An electrostatic powder gun functions as follows: powder paint is supplied through one channel, and compressed air, which must be dry and clean, is supplied through the other.
Inside the gun, the particles of the dye are charged at a power of 60-70 kW, which gives them the opportunity to be attached to the surface. This is how coloring occurs. Almost all powder paints are effectively charged, ensuring high-quality coating.
The electrostatic method has its drawbacks, among which it is worth noting the emergence of an electric field between the spray gun and the surface being treated. This reduces the quality of powder paint spraying on surfaces with complex terrain. At the same time, the thickness of the coating decreases.
This effect is called the reverse ionization effect. To avoid creating one when painting, you should extremely accurately calculate the distance from the nozzle of the spray gun to the surface, be sure to take into account the electrostatic characteristics of the powder paint, properly ground the device and regulate the current.
The essence of technology
Technologically, the use of this type of paintwork material differs from standard painting, when brushes and rollers are used. The composition is applied in the form of a dry mixture, and not in liquid form. So, to understand the essence of the work, two main stages of painting will be considered:
- The powder coating is transferred to the base;
- The effect is permanent.
When a charged powder is sprayed using equipment for polymer painting. It is applied to the base with a different type of charge. This is how the coloring matter settles on the surface.
However, such a distribution is not enough to ensure reliable coverage. A consolidation step is required. A heating method is used to make the paint “boil” on the base. A special camera is required for this purpose. As a result of melting, the layer is firmly fixed to the base.
A heating method is used to make the paint “boil” on the base.
Camera
Carrying out the work will be impossible without a special camera. This is where most of the entire process is performed. The powder coating chamber is needed for air purification (recovery process), in addition, it is due to it that the material can be reused. Here, paint that does not reach the surface being treated is sent to filters and then discarded.
Such equipment can have different sizes. Which one to choose should be decided individually in each case, having previously determined which products you plan to work with.
Powder painting equipment: selection and self-production
Some of the equipment can be made with your own hands, but this is often too difficult and time-consuming. For this reason, it is still better to purchase some devices ready-made rather than try to create homemade versions.
Some of the equipment can be made with your own hands, but this is often too difficult and time-consuming.
Spray
The application stage is the most important; the final result depends on how the layer is laid. Therefore, it is recommended to use ready-made guns to obtain a beautiful and reliable coating. The electrostatic gun is popular; it allows you to cover any type of surface, the product consumption is low.
There is also a tribostatic type, but its use requires more paint, and it is difficult to regulate the temperature required to start the application process.
All devices must be grounded.
Therefore, it is recommended to use ready-made guns to obtain a beautiful and reliable coating.
Painting chamber
The camera can be replaced by an ordinary space, which must be clean, the entrance must be covered with a film covering. But this option is for one-time use. If painting will be done frequently, then more thorough equipment will be made:
- A suitable frame structure is being welded;
- Iron sheets are installed on the outer walls; the inside walls are covered with heat-insulating sheets;
- To make it easier to collect the remaining paint after work, it is advisable to make a lattice floor covering;
- Forced ventilation is created.
If painting is done frequently, then more thorough equipment will be made.
Bake
The oven must reach high temperatures to a certain level. You can do it yourself, but the process is complex and requires skill and the availability of many materials. Therefore, it is better not to resort to such a solution.
The oven must reach high temperatures to a certain level.
Spray guns
Powder dye is a solid mass that consists of many small particles. It does not need to be kneaded and therefore, as mentioned above, this dye has become very popular.
At first, this paint was made for the oil industry as a coating like varnish. It was needed to make enterprises safer and free of fire hazards.
But gradually it flowed into everyday life and is now used for painting cars and other things.
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There are two ways to paint objects with dry paint - spraying or dipping.
The first method is accessible to almost everyone, the second is more problematic, since it is needed for very large objects and products - up to several meters in length and width.
After painting, the item should be dried in the oven so that the paint adheres better. This method requires large dimensions of the room for painting; doing it yourself is problematic.
But to paint anything at home, you need to use a paint gun, which can be easily purchased at a hardware store.
There are two types of such guns - tribostatic and electrostatic. The first type is simpler - the paint simply comes out of its container to be sprayed onto the surface.
However, this device can only spray epoxy paint. If you use other types of dry dyes, then you need to mix them with various solvents and mixtures.
The second type of pistols is electrostatic. This device has a more complex design than the first one.
The principle of its operation is the creation of an electrostatic field in which a low-frequency signal penetrates the electrode and forms a field, after which paint particles are sprayed. The electrostatic gun is suitable for almost all types of dry paint.
Depending on the above characteristics, you need to make your choice, but you must remember that such equipment is not cheap.
If you don’t plan to do any grandiose coatings with dry paint yourself, then you can purchase a tribostatic gun.
It contains paint in a 0.5 liter container; you can change it if necessary. Although its design is quite simple, it can serve you for a long time and paints small and medium-sized objects well.
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True, one of its disadvantages is that the parts that make it up quickly become unusable, but they can be replaced.
If you need to paint large volumes, then electrostatic guns are suitable - they paint even better than the first ones, the layer is more even, but they paint medium and small products with a complex design worse.
Powder coating lines: automatic and semi-automatic
Lines for powder coating are automatic, manual and semi-automatic. The latter are cheaper compared to automatic ones, but they are more difficult to work with, although the effect is good.
The automatic option, as the name implies, allows you to minimize manual labor, but they will be expensive.
Lines for powder coating are automatic, manual and semi-automatic.
Business organization
These works in specialized centers today are quite expensive. If you want to try yourself in this business, then if you have financial resources, you can start. Of course, not everyone can afford a powder coating line (automated system), but thanks to our recommendations, you will be able to replace some elements with other tools at first.
Start with small items. These can be plaster figurines, ceramic dishes and much more. Try painting something in your home first (start with something you don't mind ruining). Gradually you will develop the necessary skills and dexterity, then you will be able to accept orders from friends. However, you shouldn’t expect much income if you rely only on one-time orders from individuals.
The best case scenario involves the presence of large start-up capital. In this case, you can immediately purchase the necessary equipment and hire workers. Clients should be sought among enterprises engaged in the production of metal products. Only the presence of such customers will allow your business to exist and develop.
What to look for when choosing powder coating equipment
Powder coating installations can often require a lot of space to be fully applied, which is why it is important to estimate the size before purchasing a line. The following points are also taken into account:
- The type of products that will be painted, if they are small, then the use of large equipment will not be required;
- The choice between a gas and electric oven is not fundamental; it is made based on the preferences of the master;
- An electrostatic spray gun is preferable for large objects, and a tribostatic one for small ones.
Before purchasing a line, you need to estimate the size in advance.
To apply modern powder paint, you will need several devices. They should be selected based on the volume of work, financial capabilities and working conditions.
Tribostatic spray gun
A tribostatic powder gun or spray gun works on the principle of multiple collisions and friction of powder paint particles, as a result of which they are charged. This process occurs in a special unit of the gun, where the particles actively interact with each other.
Since the use of current is eliminated during charging, there is no electric field, which means there is no reverse ionization effect.
This gives the following advantage: powder paint freely penetrates into all hard-to-reach places of the relief and porous surface and is evenly distributed, which guarantees the quality of spraying. It also becomes possible to paint the surface multiple times, achieving a layer of the desired thickness.
Among the disadvantages of the tribostatic painting method, one should note a limited selection of paints, mandatory sandblasting of metals before painting, and low productivity. And the tribostatic powder gun itself has proven itself to be a very capricious device in operation.
Equipment and use of tribostatic sprayer
Powder paint appeared on the market not so long ago, but has successfully gained fans due to the success of its application. It allows you to create a high-quality and durable coating with a special mass (powder). This powder is easy to work with; you do not need to mix it or perform any complex actions with it. Initially, this paint was intended for oil refining production, but then it gained popularity in other areas, in particular small-scale production.
- it is convenient for working with objects of various configurations (both small and large);
- it is easy to use and operate;
- has high impact resistance;
- It is possible to regulate the application of a certain layer of paint in thickness.
You can buy a tribostatic gun in the following configuration: pneumatic gun, material tank, sprayer. The simplicity of the design determines the high properties of powder painting and high performance. The tribo sprayer is easy to adjust the spraying speed and has no electrical elements.
The tribostatic gun is offered to buy with various parameters depending on the customer’s needs. The average nominal productivity is 2.5 square meters per minute, air flow is no more than 3 cubic meters per hour, weight is no more than 1 kg.
Design Feature
The design varies depending on the type of equipment used, since tribostatic guns generally have fewer components. This is a working handle, a tank or funnel, a nut, the inner rod of the tribostatic barrel and the body of this barrel. The gun itself is connected to the compressor. Electrostatic guns are somewhat more complex in their design, since there is a housing with a control panel, a paint tank, a converter with a power supply, a spark gap, an electrode with a nozzle, and cables.
Important. For electrostatic guns, it does not matter what type of powder paint is used.
It can be polyurethane or polyester powder. The painting efficiency will be the same.
