Powder coating is a modern surface finishing process used in many industries. A dry powder coating is electrostatically applied to the workpiece to be coated and then baked at high temperatures. This method offers numerous advantages, including an extremely durable and uniform surface, high environmental friendliness due to the elimination of solvents, and efficient use of the material, as excess powder can be recovered and reused. Powder coating is used in a wide range of industries, from the automotive and construction industries to household appliances and furniture, and impresses with its versatility, durability, and aesthetic quality.

Powder coatings are specialized coating materials used in powder coating. They consist of finely ground particles, typically containing resins, pigments, fillers, and various additives. These particles are applied to a conductive substrate using an electrostatic process. Once the powder is applied to the surface, the workpiece is placed in an oven, where the particles melt and cure into a uniform, durable coating.

Powder coatings offer numerous advantages over traditional liquid coatings, including:

1. Environmental friendliness : Powder coatings do not contain solvents, making them a more environmentally friendly alternative.
2. Efficiency : Excess powder can be recovered and reused, minimizing material consumption.
3. Durability and resistance : Powder coatings are very robust and offer excellent resistance to scratches, chipping, chemicals and weathering.
4. Uniform coating : The powder adheres evenly to the surface, resulting in a uniform and high-quality final coating.

These properties make powder coatings and the powder coating process widely used in many industries, from automotive parts to furniture, household appliances and architectural components.

Our technical data sheets provide useful information about powder coatings, their processing, test results, and other useful information at a glance. Feel free to download the data sheets you're interested in. You can find the relevant data sheet directly on the product page, or all data sheets are listed below:

Primer (100 series)

• Matt grey
• Mixed powder

Clear Coat Colorless (110 Series)

• Shine
• Dull matt
• Metallic
• Anti-graffiti

Metallic shades (210 series)

• Shine
• Frosted
• Fine structure

RAL colors (120 series)

• Highly weatherproof (130 series)
• High gloss
• Shine
• Silky shine
• Satin matt
• Frosted
• Dull matt
• Fine structure

Special colors

• Heat-stable (510 series)
• Glazes (310 series)
• Wrinkle effect (322 series)
• Chrome effect
• Croco Effect (322 Series)
• Fluorescent colors (120 series)

Most powder coatings require temperatures of 180°C. The time the objects spend in the curing oven is approximately 15 to 20 minutes from the object temperature on the surface. Primers require less time; 15 minutes at 180°C are sufficient. The powder can be gelled and then baked with the topcoat to save time. Heat-resistant powder coatings require a higher curing temperature of up to 200°C and a longer time in the oven.

Detailed information on the respective powder coating series can be found in the technical data sheets.

Most powder coatings can be applied using the corona and tribo application methods. Metallic coatings require verification of their suitability for the tribo process. We have already described these two application methods in more detail in our blog posts.

Note for multi-layer systems: For inexpensive coating devices on which no settings (current/voltage) can be changed, it must be checked whether a multi-layer structure is possible.

Before coating, all residues of grease, oil, scale, and oxidation products must be completely removed from the surface to be coated. Depending on the workpiece and project requirements, it may be advisable to blast and/or prime the workpiece. Further information can be found in the technical data sheets.

General information

This section provides processing recommendations and information on the properties of metallic effect powder coatings. Detailed information at a glance, such as curing temperatures and other information, can be found in the technical data sheets. Metallic effects are created by the light reflection, light absorption, and specular effect of the metallic effect pigments contained in the coating. Different color and/or effect impressions are achieved through type, quantity, and orientation. In addition to the processing parameters common to all powder coatings, which are beyond the control of the powder coating suppliers, the following points must be observed with metallic effect powder coatings. "Non-bonded" (dry blend) metallic effect powder coatings are often more sensitive than "bonded" metallic effect powder coatings.

Preparation

Generally speaking, coating with metallic powder coatings is more demanding than applying solid colors, such as RAL powder coatings. Therefore, the optimal settings for the coating system should be determined and noted in advance tests so that they can be adjusted later during the coating process. It is recommended that the same spray guns be used every time. Powder coatings are manufactured industrially and are therefore subject to certain raw material and production fluctuations. Despite the most careful work procedures, differences in color or effect between different batches cannot be avoided. We therefore recommend that a prior incoming goods inspection be carried out under standardized conditions. However, an assessment according to the guidelines for RAL powder coatings is not applicable to metallic effect powder coatings. Therefore, object-specific workpieces should be coated with the same batch.

application

To avoid unacceptable color/effect differences, we recommend identifying these areas at the beginning and then continuously monitoring them during the coating process. If necessary, problem areas of the workpiece should be "pre-coated." Recoating these areas may lead to color/effect variations, which could detract from the overall appearance. Further information can also be found in the technical data sheets.

Recovery

Continuous dosing of fresh powder. A consistent ratio of fresh powder to recycled powder is desirable for all metallic effect powder coatings.

Generally

The glazes are transparent, colored powder coatings, so the substrate is crucial for the color result. Light-colored surfaces make the color more radiant and bright; for a "candy effect," we recommend our Chrome Effect Powder. The color of a glaze always depends heavily on the layer thickness; thicker layers generally produce richer, more intense colors. Layer thickness differences of even 20 μm result in a visual color difference and therefore do not constitute a defect.

application

When using the glaze in a multi-layer system, such as with our Candy Set, multiple coats are required. First, the primer is baked or gelled, followed by the base coat for the glaze. Chrome effect powder is often used for this. After this layer is baked, the glaze is applied. The multi-layer structure increases the layer thickness, making it more difficult to achieve adhesion between the powder coatings if the coating equipment is not properly adjusted.

With inexpensive equipment, it's possible that settings cannot be changed, making processing impossible. However, "hot coating" can be used with simple equipment. Here, the workpieces are not cooled after the baking process, but are immediately coated while still "hot." The powder coating adheres to the hot surface and can be baked again once all areas have been evenly coated. For complex geometries, it's recommended that the most difficult areas be coated first.

The cleaning ability and chemical resistance depends on several factors:

• Composition of the powder coating
• Type and concentration of cleaning agents or chemicals
• Type and exposure conditions of the contamination

When cleaning, it is essential to follow the manufacturer's data sheet (powder coating and cleaning agent) and the applicable regulations of the various associations (e.g., GRM, GSB, Qualicoat). Abrasive cleaning agents are not recommended. Soiling should be removed as quickly as possible to avoid permanent damage to the surface. For demanding applications, a suitable transparent overcoat can improve cleanability, chemical resistance, and protection against mechanical stress.

A few basic principles should be observed when powder coating to achieve the best possible results. We've provided a clear overview of the most important powder coating tips:

application

We recommend always ensuring proper grounding of parts. Pre-coating is always recommended for complex geometries. Post-coating may result in clouding, fading, and backspray (overcoating). For parts that are to be coated on both sides, coat the main visible surface last. Settings, such as high voltage, conveying, dosing, or purge air, as well as the distance to the workpieces, should not be changed during the coating process, if possible or available.

Defect patterns in powder coating

In powder coating, various errors can cause visual impairment in the paint film. A common mistake is overcoating, which can result in a so-called "orange peel" effect. Due to a lack of coating thickness measurements, the optimal coating thickness of the paint on the substrate surface can only be estimated. Experienced powder coaters have different techniques for using the powder gun when spraying the surface. This allows for a more precise layer thickness. Spray robots achieve the most homogeneous surface through precise adjustments.

Powder coatings

The layer thickness for a "single coat" of metallic and RAL powder coatings should be neither too thick nor too thin, between 80-100 μm and a maximum of 120 μm (can vary depending on the powder type). Excessive layer thicknesses often lead to visual impairment. Powder coatings with a smooth surface texture develop an "orange peel" effect, a textured/dented surface. If possible, only powder coatings from the same production batch should be used for a single coating application. To do this, it is important to correctly estimate the required quantity; the theoretical yield for each powder coating can be found in the product description or on the technical data sheets. When overcoating (e.g., with transparent coatings, repair paints), it should be noted that this can lead to a change in the overall appearance.

Packaging and transport

For storage and transport of coated workpieces, select suitable, non-abrasive packaging material. Direct contact between coated parts must be avoided.