Powder coatings are well known in the architectural world for delivering tough, durable protection. Hopefully, by now you’re also aware that they deliver an improved environmental footprint over competing liquid coatings. There are, however, many myths and misconceptions about powder, its suitability to various applications, its technical performance and its role in assisting the architectural community in reaching ambitious sustainability goals.

With that in mind, we compiled a list of top ten ‘myths and mistakes’ covering the most common questions we are regularly asked, from specifiers, architects, and designers alike. Before diving in get into that, let’s start with a quick refresher on the basics.

Powder is essentially a type of performance paint, designed to deliver beautiful, tough protection to metal substrates, with the added bonus of an improved sustainability footprint. It’s a factory applied finish, usually applied to architectural aluminum and steel (powder coating for heat sensitive substrates like wood and MDF is also now available; more on that later). The coating is electrostatically applied and then cured in an oven resulting in an attractive, hard-working finish. There are multiple types of powder coating, with a wide variety of performance capabilities, from chemical and stain resistance, to long term exterior color and gloss retention, and corrosion protection. Due to the huge variety of technical performance possible, powder is also applied to a wide variety of architectural applications: from rebar and piping to curtain wall, windows, panels, façade elements, perforated panels, railing and fencing, as well as a multitude of interior applications in the monumental, commercial government, education, residential, retail and hospitality spaces.

Now that we have the basics covered, Let’s look at the most common questions we get asked about architectural grade performance powders.

1. How can you possibly put powder on a building façade? I put it on my bike/furniture/shelving – it’s not going to be durable like a performance liquid paint.

This is probably the most common misconception with powder. “Powder coating” is actually a generic term – it covers lots of different product types/chemistries that are suited to many different applications. We make all sorts of different powder coatings, and we certainly don’t put the same type of powder coating on the curtain wall or façade of a building as we do on a refrigerator or a bike! There are 3 different architectural grades of powder coating that are aligned with the architectural industry coating standards, the AAMA performance specifications:

Fluoropolymers: Superior performance FEVE Fluoropolymer powder, like IFS 500FP, will meet and exceed the performance requirements of AAMA 2605. In terms of technical performance, it is equivalent to 70% PVDF liquid paints and it also boasts an improved environmental footprint. Like PVDF paints, these powders are used for exterior applications like curtain wall, façade elements, windows etc. and come with a 20 year warranty when applied by a Registered Applicator to architectural aluminum.

Super Durable Polyesters: High performance super durable powders, like IFS 400SD, are designed for exterior applications and will meet and exceed the performance requirements of AAMA 2604. Super durable powders are often used in exterior applications like commercial storefront, low-rise curtain or window wall, windows, railing and come with a 10 year warranty when applied by a Registered Applicator to aluminum. In recent years, super durable powders have also been utilized on some interior applications, like mullions or areas where specifiers are worried about the potential for interior fade. These super durable polyester powders deliver excellent color and gloss retention when compared with a standard polyester powder (more commonly used on interior applications) and are also extremely competitively priced.

Standard Polyesters: Standard polyester powder coatings, such as IFS 300SP, are generally recommended for interior use within the design community. They will often meet and exceed the AAMA 2603 performance specification, which provides limited exterior durability, but in the architectural world are best suited to interiors.

Of course, other chemistries are also available, e.g. epoxy-based powders which are commonly used as powder primers, or urethanes, or even hybrid powders – but the above are most commonly seen in the architectural space.

2. I thought fluoropolymer coatings were just the realm of 70% PVDF liquid paints, is that not the case?

Just like liquid fluoropolymer coatings, powder fluoropolymer coatings will meet and exceed the performance requirements of the AAMA 2605 specification.  They may both perform in the same way, but where they differ is in the type of fluoropolymer resin used. As the name suggests, PVDF liquid paints use polyvinylidene difluoride (PVDF) fluoropolymer resin, which you might recognize from the “must contain minimum 70% PVDF resin content” line in your spec. Powder fluoropolymers, like IFS 500FP, use FEVE (fluoroethylene vinyl ether) resin. While both are fluoropolymers, the chemical structure is different. FEVE fluoropolymers use the carbon fluorine bond, which is extremely difficult to break, to deliver incredible long term weathering and durability. An added advantage of FEVE Fluoropolymers is that they often only require a single coat on aluminum – but deliver the same technical performance and film thickness as 2 or 3 coats of liquid PVDF.

3. I’m confused about the number of coats required. Please can you explain what I need and if performance is affected?

With powder it is pretty simple; it comes down to substrate. 99% of the time, over properly pretreated aluminum, powder is a single coat application. Color, location, special effects don’t matter– it is a single coat. Even mica/metallic effects are single coat with powder simply due to the different way we make them.

For steel, however, two coats of powder are usually recommended. This is due to the limitations of steel pretreatment compared to aluminum. In these cases, a powder primer is applied first. If corrosion is a concern, depending on the type steel used, a zinc rich powder primer can be utilized, plus the powder top coat.

It therefore goes without saying that the language around number of coats in the specification should reflect this.

4. With this in mind, are warranties available for architectural grade powder coatings on exterior applications?

Absolutely. 20 year warranties are available for fluoropolymer powders and 10 year warranties are available for super durable powders, if the powder is applied by a Registered Applicator to architectural aluminum. The warranties usually cover things like color and gloss retention, chalk etc. but it’s always worth checking exactly what the coater who is applying the powder and therefore offering the warranty promises.

5. What is a Registered Applicator and how do I find one?

There are many different types of powder coating applicators, from fabricators like SAPA and Kawneer, to OEMs like Construction Specialties and window companies like Sierra Pacific and Starline, in addition to professional custom coaters of all sorts of different sizes and capabilities. A Registered Applicator is one that has passed rigorous auditing and testing procedures to confirm that the coatings they apply meet or exceed the performance standards of the relevant AAMA coating specifications. They are also retested regularly to maintain this status and are authorized to offer a warranty. There are Registered Applicators all over the USA and beyond, and the number is growing all the time. Your powder supplier can provide a current list of Registered Applicators.

6. Why do powder coatings have a better sustainability footprint than liquid coatings?

Powder coatings offer many environmental advantages over traditional liquid performance coatings. They contain no solvents, which means they emit  negligible VOCs. They also require fewer coats and lower curing temperatures, which contributes to a reduced carbon footprint. Additionally, any overspray can often be reclaimed, reused or recycled, minimalizing waste. Powder does not required a chrome based pretreatment and a chrome based primer is never used. With IFS Coatings, manufacturers Environmental Product Declarations (EPDs) and Health Product Declarations (HPDs) for architectural grade powders are also available.

Specifiers often hold the key to moving the industry forward in terms of improved sustainability footprint. If the products with a better environmental footprint are not included in the project spec, then often there is simply no option to use them. As powder is known for its improved sustainability footprint when compared to equivalent liquid coatings, adding powder into the spec is easy to do and can reap multiple benefits, both environmental and financial.

7. I’m specifying powder for the first time – what should I watch out for in my specification wording?

Firstly, don’t take liquid out of your spec, add powder in. Make it about performance, which opens up the project to benefitting from sustainability advantages and potential cost advantages.  Many architectural firms have made powder their first performance coating of choice, followed by the equivalent performance liquid coating, signaling to the industry that sustainability is important. This is what drives change.

When it comes to wording, pay close attention to percentage of resin and number of coats. Most performance coating specs start with the number of coats. Remember, powder coatings typically achieve the same performance with fewer layers, so your spec language should reflect this.

Unlike PVDF liquid paints, which use 70% Fluoropolymer resin, FEVE Fluoropolymers use 100% Fluoropolymer resin. The resin is what gives the coating its durability and weatherability, so this is a major advantage. Most specs need to change the wording to reflect this.

Most reputable powder manufacturers will have guide specs and finishing language available, as well as experts happy to review and make suggestions to your specs. The Powder Coating Institute (PCI) also has a useful page which includes a three part guide spec: https://www.powdercoating.org/page/ArchitUse

8. Can I use powder on steel?

Yes, and it’s used regularly. Regardless of the type of steel, a powder primer is usually recommended. A zinc rich powder primer can be used if corrosion is a concern. After blasting and pretreatment, the powder coating is applied and cured in the same manner as on aluminum. It’s worth noting that like liquid paints, most companies do not provide a warranty for coatings on steel substrates.

9. Where aren’t powder coatings used in the architectural arena?

Generally speaking, wherever you can use liquid performance paints, such as 70% PVDF paint, you can use equivalent powders. However, the most common answer to this question is coil. At this moment, the economics of powder coating coil simply don’t match the economics of liquid coating coil, so it’s simply not done.

10. What’s new in powder coating?

There is so much happening in the world of powder that the architectural community can benefit from!

As well as the applications discussed above, rebar has benefited from powder coated protection for years. Functional Bonded Epoxy (FBE) green powders are widely used in this market and recent developments have seen a new dual layer, textured epoxy coating system designed to provide a DOT bridge engineer with an option to specify rebar that will provide a 100 year bridge design. The base layer is the same fusion bonded epoxy used on rebar since 1973 to provide the best corrosion resistance in the industry. The difference is the innovative, next generation textured top coat.  The top texture layer provides several benefits, including excellent concrete adhesion and additional field damage tolerance.

On the decorative side, incredible new colors include beautiful “blackened” looks, color changing effects and even previously difficult brights, all available in AAMA 2605 level powders.

Finally, in terms of substrate, low cure powders for heat sensitive substrates like wood and MDF are gaining traction across industries, delivering all the benefits of powder, from technical performance to an improved sustainable footprint, to industries from siding to cabinets, furniture and beyond.

This article barely scratched the surface of information and resources that are available to the design community. Interested in learning more? Attend educational lunch and learns, download the free e-books, talk to the experts, and ask for help! There’s a wealth of coating knowledge available to you and we’re ready to assist!