Powder coating is a modern, progressive method of painting metal products. Powder paint guns create the most durable, resistant, and durable coating. If the technology of applying the material is observed, the coating can last up to 20 years.
Powder coating near me
The main difference between powder coating and all other types of paint and varnish materials is that it requires special equipment. These are a spray gun, a spray chamber, and a polymerization furnace.
The durability and uniformity of the final coating depend on the quality and correctness of the selection of devices. In this article, we will tell you how to choose a gun for painting metal products with powder.
Powder Paint Sprayer: How does a Gun Work and what types are there?
The name of powder coloring was given to the method of forming coatings with polymers that differ in increased properties in terms of decorative and protective parameters. For the first time, the technique was developed back in the 50s of the last century, but they did not think about pistols at that time.
At its core, the powder coating gun system is an alternative option for the use of liquid compositions on surfaces subjected to thermal treatment. A special gun for powder coating is the main tool that is used when performing this work.
What is the essence of powder coating?
Powder paint is usually sprayed on a clean metal surface. From an external source, the material particles receive an additional charge or electrification, in which the powder paint sprayer participates, occurs during friction.
The field using electrostatic particles contributes to the fact that the dye itself combines with the metal, which has the opposite charge. Particles that have not settled on the surface are collected inside the paint spraying chamber and electrostatic equipment. They can be used for repeated staining with a spray gun.
After the completion of the previous stages of work, the painted parts are placed inside a special chamber for polymerization.
Powder paints lead to the appearance of a monolithic structure of high quality, a surface layer is formed. This structure provides additional protection to the base material.
The coating is formed by using the method of heating the painted layer until it begins to melt. Further refinement contributes to hardening. For materials with thermal plasticity, on the contrary, cooling is carried out at this stage.
The result of processing is the appearance of a special film on the surface; a smooth and durable polymer coating is obtained. This means that it was possible to paint with powder.
The principle of operation and the necessary equipment
The essence of the operation of this equipment can be divided into three main steps:
- Paint is poured into the spray gun and equipment is connected to electrify the material particles. They receive a charge when passing through the channels of the atomizer.
- The processed part is grounded.
- Charged paint particles are applied to the metal surface.
In addition to the spray gun itself for powder painting, the processing line includes a certain set of nodes, the list of which is below.
- a container for powder coating.
- stands for fixing products, with mounting clips and hooks.
- automatic lines for moving the stands to the chamber for subsequent processing.
- the spray chamber.
- a cyclone for charging paint particles.
- unloading chamber.
- chamber for heating and polymerization of powder material.
- lighting devices.
- the compressor.
If we talk about the scheme of the powder paint gun itself, then it is as follows:
- The air supply channel.
- A line for feeding paint.
- Charging surfaces.
- Powder mixture.
- The head for spraying the finished composition on a metal surface.
Types of guns for powder coating
Powder coloring can be done in two ways: by immersion and by spraying the dye. The first option is a very complex technological process; therefore it is used only in production conditions for painting large-sized objects (profiled flooring, metal structures, and frames).
The method of spraying is carried out using a gun; this method is available for painting at home. The principles of the functioning of pistols allow us to divide them into several varieties.
Electrostatic Paint Gun
The electrostatic paint gun allows you to process surfaces regardless of what shape they have. Promotes the appearance of ultra-thin coatings, usually, their thickness reaches only 30-250 microns.
This is an economical option that will not be labor-intensive when engaged in maintenance. Therefore, such a gun is a leader in the modern market. If necessary, it will not take much time even to replace the paint.
When using such tools, it is not necessary to preheat the surface. Of the main disadvantages, it is worth noting the high cost, not everyone can apply such a powder coating.
The tribostatic gun is distinguished by the absence of a particle generator in the usual sense of the word. The formation of a charge is carried out due to the fact that the particles of the paint material rub against each other.
The difficulty of obtaining a sufficient amount of charge with paint is the main difficulty faced by owners of tribostatic devices when conducting coloring. It is required to carry out a clear adjustment of the primary paint.
The quality of charging strongly depends on the humidity level with which the tribostatic equipment operates. The powder precipitates too quickly, and the charge itself decreases when working on any type of surface.
This type of sprayer is designed to apply the paint in layers. Therefore, it is easy to gain sufficient thickness. It is usually at the level of 250 microns. Thanks to the use of technology, it is easier for the master to monitor what the thickness of the spray remains at any given time, using a spray gun.
Preparatory work, operation of the coating, and sprayer in this case are really cheap, do not require additional expenses. But this option also has disadvantages, including:
- the requirement for the presence of a simple form at the treated surface, on which the powder spraying process is organized;
- the need, in any case, to pre-heat the part with your own hands, and then dry it;
- increased paint consumption during surface treatment;
- this technology also requires the use of metal that is resistant to high temperatures.
Powder gun design
The spray gun for powder coating, of course, differs from its industrial counterpart in power, small dimensions, a paint hopper, and other parameters. At the same time, it makes it possible to perform a very diverse work on applying paint to many materials.
A standard powder gun consists of the following elements:
- hopper for powder coating,
- buttons for switching on,
- knobs for adjustment,
- power supply,
- grounding wires,
There are two main methods of applying powder paint using a powder gun – it is electrostatic and tribostatic.
The first method is considered the most effective and is suitable for epoxy, polyurethane, and polyester powder materials.
The second method is less productive and allows you to use only epoxy paint, while other powder materials can be used only after mixing with special additives.
Principles of applying powder paint
Powder coating is fundamentally different from the traditional liquid. Here, the process of applying the coloring substance does not occur in the form of a viscous substance (which is ejected from the nozzle of the spray gun under the influence of mechanical energy), but in the form of tiny particles of dry dye.
The particles adhere to the surface to be painted due to their electrification, as a result of which they acquire a charge different from that possessed by the surface. Then everything happens in accordance with the well-known Coulomb’s law on the attraction of dissimilar electric charges. The electrification force determines the strength of the coupling.
The acquisition of initially electrically neutral particles of a positive or negative charge can occur by two methods:
- Electrostatic, when a powder particle is charged from an external source. Therefore, powder guns that implement this principle are called electrostatic;
- From the kinetic energy of friction between adjacent particles that fly out of the nozzle of the paint gun at high speed. Since the tribostatic effect is used in this case, the pistols received the same name.
Regardless of the energy source that charges the powder, the uniformity of the charge level leads to the fact that the settling of the particles of the coloring substance occurs much more evenly, and is not associated with pressure drops of the compressor, the force of pulling the trigger and other factors.
In addition, dry powder paint is more environmentally friendly, since it does not contain toxic organic solvents. However, it is recommended to use a respirator when painting.
There are also limitations in the use of powder paints. For example, in order to increase the surface activity of the painted surface, it is recommended to heat it up to 150 … 200°C. Otherwise, the coupling force of dissimilar charges decreases, which will affect the durability.
How does a powder coating gun work?
Modern paint and varnish materials allow you to create a high-quality and durable coating on any surface, regardless of shape and texture. One of the most popular novelties can be called powder paint. This raw material is a solid, finely dispersed mass that does not require additional kneading. This type of paint has become a real breakthrough in the field of finishing coating. Initially, powder paint was developed for the oil refining industry as a paint and varnish coating (LCP) with an increased protection index. At the moment, powder paint is actively and universally used in everyday life and the automotive industry.
Safety rules at work
Paints in the form of powders are not among the materials that require safety measures when using them. But some dangerous substances are still present in their composition. This applies to resins-epoxides, allergens, cadmium, substances for curing. Before starting powder coloring, you should familiarize yourself with some rules, compliance with which will allow you to perform the work without harm to your own health:
- Before painting, it is necessary to inspect the powder gun for serviceability and operability.
- It is allowed to carry out painting only in rooms with good ventilation, it is impossible to spray paint in completely isolated places (windows must be open).
- In the room where the powder coating of metal is planned, it is necessary to check the grounding. Also, remember that at high temperatures there is a risk of paint ignition, so do not work near a fire.
- When starting work, be sure to wear personal protective equipment: rubber or cotton gloves, special glasses, a respirator, as well as protective clothing designed for protection during painting work.
Features of powder paint
The powder paint coating has a complex chemical structure. Such a strong and reliable raw material can be obtained by fusing two heat-resistant paints of different chemical compositions.
After being applied to the surface, the coating forms a layer of a protective film. The film is resistant to the external aggressive environment and allows you to keep the metal from corrosion.
That is why paint has become so widespread when painting a car. According to the type of raw materials, they can be divided into thermoplastic and thermoactive paint, which differ in composition and quality properties.
The paint does not react chemically with the metal, and the frozen film has the same chemical composition as the raw material. That is why the metal does not succumb to the negative consequences of applying paint.
The main active substances are polyamide and polyethylene. Paints do not require additional treatments, the addition of solvents and thickeners before use. The product form is a paste ready for use.
Advantages of powder paint:
- the coating is resistant to high temperatures and moisture;
- resistant to aggressive reagents;
- it has a protective vandal-proof crust that prevents minor mechanical damage, wiping, and burning out of paint.
- high price;
- the need to use specialized equipment.
How to choose a gun
In order to buy a paint gun that will perform the necessary tasks and serve for a long time, first decide which products you are going to paint. If it is a large number of products of a simple shape, it is better to buy an electrostatic gun. If you have to paint products of complex shape, then the ideal option is a tribostatic gun
But if you need to paint a huge number of parts of complex shape, it is better to install an automatic production line.
It is also necessary to determine which layer of the final coating should be. The tribostatic gun allows you to get a thicker coating.
Remember that tribostatics is much better at coping with hard-to-reach places and corners. But it is not suitable for long-term, continuous painting.
If after reading this article, you could not figure out which gun to choose for painting, then we advise you to consult a specialist for recommendations. He will be able to choose the necessary tool, taking into account all the features of production.
The use of pistols involves complete cleaning and degreasing of the painted surface. For the surface preparation process, there are specialized phosphate detergents. After degreasing, the surface is dried and heated.
Given that tribostatic pistols are usually used in everyday life when everything is ready, you can start mixing the coloring substance. If the paint is epoxy, then it does not require preparation.
Powder paints of other brands require mixing according to the instructions on the package. If the operating rules are followed, the powder coating looks perfectly smooth. And it also serves for a long period, despite external negative factors of influence.
Despite the fact that powder paints are harmless, working with them has certain nuances.
- Before you start painting, you need to wear clothes for painting work, protective glasses, a respirator and rubber gloves.
- Staining should be carried out in well-ventilated areas. It is advisable to carry out all work with paint materials on the street.
- Some paints contain flammable substances. Therefore, it is important not to work with powder paints near a fire.
- Before starting work, it is necessary to check the spray gun for serviceability. And it is also necessary to make a thorough adjustment of the airflow, setting the necessary spray parameters.
- If you plan to paint metal products, there must be grounding in the room. And also before starting work, metal parts must be degreased.
- When choosing paint for coloring, you should carefully familiarize yourself with its characteristics. After all, the density of matte and glossy coatings differs. And this can affect the operation of the sprayer.
- When painting, you need to make sure that the sprayer is at an angle of 90° with respect to the painted part.
Coloring with powder paints can facilitate the entire painting process. Buyers are only required to carefully prepare and carefully familiarize themselves with the parameters of the spray gun.