Liquid or powder coating: which one to prefer and why?

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Have you ever wondered what advantages a powder coating brings over a liquid one? Read on to clarify any doubts.

Right from the first phase, it is necessary to be clear about the end use of the item and consequently choose the correct materials and coatings to avoid nasty surprises. Coating a surface means improving it aesthetically and protecting it from wear, chemical agents, and weathering.

Powder coating is the process used to coat metal materials with a thin film of powder coating based on synthetic resins. The powder, previously negatively charged using an electrostatic gun, is sprayed onto the grounded metal surface to ensure perfect adhesion. Innovative technologies now also make powder coating of glass, ceramic and MDF artifacts possible.

Liquid coating is a process used to coat varied materials with a liquid film that loses solvent during the film-forming phase until it reaches the required polymerization level. Depending on the formulation technology, the film-forming phase requires a later cross-linking phase that can take place through the action of UV light, second components, or by simple remodelling of the original polymer. Liquid coatings can be applied in a variety of ways, from the most manual systems (brush) to more advanced and complex systems (e.g., robotic spraying, rollers, curtain coater).

Which is the best choice between powder coating and liquid coating?

We at RIPOL are convinced that, for metal protection, powder coatings offer far greater competitive advantages than liquid coatings. That is why we focus exclusively on the production of powder coatings, products that allow us to respect the environment and guarantee our customers a high-performance coating.

Increased resistance and durability

Powder coatings are ideal for metal substrates as they have a high resistance to UV light, weathering, and aggressive chemicals. A powder coating provides a thicker, homogeneous layer than can be achieved with a liquid coating and, as a result, it is not only more durable but also highly resistant to chipping, abrasion and scratching. Powder-coated substrates can last for decades.

The use of powder coatings also guarantees excellent edge coverage and the absence of any leaking spots in the coating.

Less coating waste

In the powder coating process, a recirculating powder that does not adhere to the substrate can be recovered with the use of suitable equipment, mixed with the virgin product and reintroduced into the coating cycle. This guarantees a reduction in overspray with an overall use of 95% or more.

During the film-forming phase, liquid coatings can lose up to 90% in weight with a high rate of volatile particles dispersing and, in the case of solvent-based coatings, VOC emissions. In addition, overspray cannot be recovered.

Cost reduction

Reducing overspray during powder coating results in less waste and consequently lower costs.

Environmental regulations concerning the dispersion of hazardous materials, such as solvents, require a quite onerous procedure to be followed in the management of emissions throughout the application, drying and residue disposal process. Producers and users of liquid coatings must be equipped with special burners capable of removing solvents or abatement filters, take compulsory safety measures for the presence of flammable liquids and set up a disposal plan for hazardous waste. Unusable powders at the end of the coating process also require dedicated disposal but, due to the absence of solvents, the costs are significantly lower than liquid paints.

Even in comparison with water-based liquid coatings, the powder coating solution has different costs and efficiencies that must be considered. Although water-based coatings have a lower VOC content than solvent-based ones, they require careful management of humidity, temperature and ventilation during application and drying.

When drying liquid coatings, the air exchange in the ovens is extremely high compared to powder coatings. This results in a decrease in thermal efficiency, safety level and, of course, a higher VOC reduction cost.

Higher productivity

Liquid coating, unlike powder coating, requires a mixing phase with other products (thinners, second components, accelerants, etc.) before use. This phase must be conducted carefully to avoid mistakes that could lead to defects in the final appearance of the workpiece. Furthermore, unlike liquid coating, which involves a solvent evaporation time and a drying time, powder coating only involves the polymerization phase. A huge time saving and, consequently, higher productivity with the use of powder coating.

Respecting the environment and reducing pollution

Powder coatings are the ideal solution for those who respect the environment: they contain no water, no solvents, no Volatile Organic Compounds (VOCs) are released and they are heavy metal-free. In addition, as they do not contain pollutants, they pose no threat to the health of operators either during production or coating.

Some kinds of liquid coatings contain solvents and are therefore highly polluting. Furthermore, very often, these types of coatings continue to emit VOCs even after application, resulting in the phenomenon of so-called indoor pollution. Water-based liquid coatings, on the other hand, while much less polluting than solvent-based ones, have a water content of more than 70 percent.

Ease and speed of application

Although powder coatings can only be used with industrial equipment, they are easy to apply, do not have to be spread and do not drop. In case of damaged areas before curing, the powder can be removed with the simple use of a compressed air gun and then applied again. In addition, powder coating involves fewer steps than liquid coating, thus enabling faster processing.

Finally, an important level of accuracy and experience of the coating contractor is essential for a successful liquid coating, while powder coatings require no special operator training.

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Do you still have doubts about using liquid or powder coatings on metals? Do you need further clarification? We are here to help you, contact us and we will clarify any further doubts.

How to avoid bubbles and porosity on powder coating applied to a cast metal surface

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Powder coating is a technique that provides an extremely durable coating. However, defects such as bubbles, pinholes, craters, or porosity can occur and, in addition to spoiling the coating’s aesthetic appearance, they can compromise its functionality, quality and durability over time. There are several reasons for these defects, but they can be avoided with a few tricks.

Substrate preparation

It is essential that the substrate is clean, dry and free of any contaminants before applying powder coating. This is especially true for exhaling substrates, such as steel castings, galvanized steel, aluminum and its alloys, as these metals can release entrapped gasses during curing. To achieve a clean and smooth surface that facilitates the coating film’s adhesion, removing all traces of oil, grease, rust, or other residues from the substrate is necessary.

Environmental conditions

Environmental conditions also affect the result of powder coating. If the environment where the application is done is too hot or too moist, this can create adverse conditions for the application.

The best conditions for application are a maximum temperature of 35°C and Humidity between 20-70 %.

Powder coating selection

Once the substrate has been prepared, the selection of a suitable powder coating becomes critical.

To achieve the best results on this type of substrate, it is important to use a quality powder coating that promotes outgassing and allows the entrapped gasses in the substrate to escape.

RIPOL’s OGF Series consists of powder coatings based on polyester resins (topcoat, single coat) and epoxy or epoxy-polyester (primer), formulated with enhanced outgassing characteristics for applications on exhalant substrates. These coatings are designed to mitigate the expulsion of gas during the powder coating curing process, preventing the generation of bubbles and promoting an optimal aesthetic result.

The OGF polyester series also offers excellent weathering, UV and good chemical resistance.

Coating Application

Finally, to achieve good coating distribution and adhesion, air pressure, electrostatic tension, distance and spray angle must be carefully adjusted, remembering to apply the coating in thin, even layers.

By carefully following all these steps, the powder coating will result in a smooth, homogeneous, defect-free and durable finish capable of meeting aesthetic and functional customer needs.

We encourage you to contact us for any questions or concerns about powder coating.

Corrosion, how to prevent it

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One of the most widely used materials in the industry sector is undoubtedly steel, a material that is easy to work with, very strong and light, but subject to deterioration if not adequately protected. The main reason for its deterioration is corrosion, a natural phenomenon that causes irreversible damage to a metal surface due to chemical or electrochemical reactions that can develop under adverse conditions such as rain, moisture, UV rays or contact with aggressive chemicals.

Corrosion can lead to the need to proceed with partial or, in extreme cases, total refurbishment of the item resulting in high monetary outlay as well as an unnecessary loss of time. Against this background, the choice of an anti-corrosion method that guarantees long-lasting protection becomes essential.

There are several criteria and products that can prevent corrosion, and the choice of method depends mainly on the environmental conditions to which the artifact will be exposed. For example, if it will be exposed to moisture or the exposure to corrosive agents such as salts or acids, it may be necessary to apply specific high-resistance coatings or use specific alloys; on the contrary, if it will be inside a heated building with a neutral atmosphere, such as a school, a low-protection coating system will be enough.

The application of a powder coating is certainly one of the most cost-effective solutions to protect and isolate steel from corrosive agents.  However, in an increasingly demanding and attentive market, it is necessary that the coating systems chosen are of high quality and able to meet the needs and expectations of its customers.

So how do you choose a quality product that can best protect a steel component?

QUALISTEELCOAT is a quality mark for coated steel that certifies protective coatings’ excellent wear resistance, durability and corrosion resistance. Holding this certification guarantees consumers that the product meets high-quality standards and has undergone rigorous testing to ensure optimal performance over time. The QUALISTEELCOAT license also establishes the expected lifetime of the coating.

RIPOL’s constant commitment to supplying quality products that are also recognized by external bodies has allowed the company to obtain, for the 7th consecutive year, QUALISTEELCOAT certification for the RIPOL Corrocare ABP primer used in combination with RIPOL 59L, 58L, 52L, 55R series finishes. RIPOL powder coating products have obtained QUALISTEELCOAT certification with a corrosivity category of C4H and C5H. This indicates that the products can be used in industrial areas and coastal areas with moderate salinity levels and in aggressive environments with high moisture levels, respectively with an expected lifetime of about 15-25 years.

In conclusion, choosing a quality coating product to protect a steel surface from corrosive agents is crucial to ensure durability and resistance over time. Therefore, choosing QUALISTEELCOAT-certified RIPOL powder coatings is a safe and responsible choice for those who wish to protect their steel products with a guaranteed, premium quality product.

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For further information or to test the product, please contact your local RIPOL sales representative.

Camouflage powder coating for military vehicles

RIPOL RAL 6031-F9 Matt Bronze Green is the new powder coating solution developed for the camouflage of military vehicles and military ground equipment

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RIPOL enriches its product portfolio with RIPOL RAL 6031-F9 Matt Bronze Green – code 61LV1G76312. The new coating is specifically formulated to meet the requirements of military standards to reduce the detection of surveillance and seeker systems in the visible and near-infrared spectral range, as it provides reflectance to the vehicle and perfect camouflage.

RIPOL RAL 6031-F9 is formulated to guarantee high mechanical resistance of all components, excellent colour stability, excellent surface hardness and perfect corrosion resistance even under extreme climatic conditions.

The new powder coating is a high-quality deep matt smooth polyester and can be used to powder-coat pre-treated steel and aluminum surfaces.

RIPOL RAL 6031-F9 Matt Bronze Green meets the requirements of Bundeswehr TL 8010-0002 Class IV Type 3, is approved according to the military equipment standard (VG 95211) and has been tested and approved by the Scientific Institute for Defence Materials and Supplies – Wehrwissenschaftliches Institut für Werk- und Betriebsstoffe (WIWeB).

The certified package also includes a pure epoxy matt primer 22LS1101120, available in brown-beige colour RAL 1011, to be used in a double-layer application to further improve the corrosion protection of the entire system.

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For further information or to test the product, please contact your local RIPOL sales representative.

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Change the look of your surfaces with RIPOL Clear-Sandy

RIPOL Clear-Sandy is the new fine-textured clearcoat that can change the look of a previously smooth-effect coated surface

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RIPOL Clear-Sandy – code 66RT3H04312 – is the new matt fine-textured clearcoat based on polyester resin, for coating interior and exterior surfaces.

Every coater is faced with the eternal dilemma of having to decide between buying a smooth effect or a fine-textured coat effect, with the result often of finding the warehouse full of similar products in both variants.

As of today, this is no longer necessary!

RIPOL Clear-Sandy is a unique coat that can change the look of a smooth powder-coated surface into a fine-textured surface, further improving its durability. Easy to use, RIPOL Clear-Sandy is a highly versatile finish suitable for treating any metal substrate.

The range of colours for a fine-textured finish has always been extremely limited compared to the endless options available for a smooth finish. From now on, withRIPOL Clear-Sandy there are no limits to colour: turning any smooth colour into a fine-textured finish has never been easier.

RIPOL’s new clearcoat is highly suitable for treating different materials such as glass, to provide an amazing satin ice effect or to easily turn the smooth powder-coated surface of a ceramic pot into a fine-textured effect. RIPOL’s innovative new finish can also be used as a topcoat over silkscreens and printings to protect them with an excellent aesthetic result. Ideal for indoor furniture or bicycles, it can be used for improving scratch and fingerprint resistance and increasing system durability.

RIPOL Clear-Sandy is an extremely weather-resistant powder coating. It offers superior protection against corrosion and abrasion as well as high levels of gloss retention and colour stability. Excellent resistance to yellowing ensures a long-lasting coating.

It can also be used to coat radiators, heating systems and industrial outdoor fabrications.

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For further information or to test the product, please contact your local RIPOL sales representative.

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New RIPOL’s ESD antistatic conductive powder coatings

RIPOL’s ESD antistatic and conductive Series includes a range of powder coatings specifically designed to meet requirements where sensitive electronic equipment must be protected from ESD (Electrostatic Discharge) due to static build-up. The coating acts as a protective film that will dissipate static charge occurring onto the surface. With RIPOL ESD coatings, valuable electronic components are kept safe in use or in storage.

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For further information please contact your local RIPOL sales representative.