Industrial Powder Coating | A Guide to Finishing Roll Formed Parts
As industrial finishes go, powder coating has become a preferred choice in manufacturing.
A hard finish more durable than paint, it’s suitable for a wide range of metal items from auto parts to furniture components.
In this guide, we explore powder coating’s application process, its advantages over other coating methods, and a number of other topics, including:
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What Is Powder Coating & Why Do Metal Components Need It?
Powder coating is a dry process that uses electrostatic charges to fuse powder pigment blends to grounded metal parts. When cured, the powder creates a chemical bond, resulting in a finish that has many desirable qualities:
- Environmentally compliant
All these factors make powder coating an attractive choice for any manufacturing project where quality finishings are essential.
The Industrial Powder Coat Process
Just as with any finishing process, there are certain steps to follow for powder coating:
- Medium preparation – The powder, a polymer resin (typically polyester, polyurethane, epoxy or acrylic) is heated, mixed with pigment and hardeners, then cooled and ground into fine particles.
- Parts preparation – Arguably the most important step in any finishing process as parts need to be clean and dry for the finish to adhere properly. Any debris left on a part will affect adhesion of the powder coat. Poor surface prep negates all the time and energy spent further down the line to coat and cure the part.
- Coating the parts – In electrostatic spray deposition ESD (the most common application process) the powder is sprayed, imparting a positive charge as it is dispensed onto a grounded (negatively charged) part and forms a bond. Some powder coating providers using ESD will do their jobs in a batch booth, manually spraying pieces to contain the powder. Others, especially those with high-volume orders, use a conveyor system outfitted with “wagglers” to spray the parts.
- Curing the finish – With ESD coating, parts need to be heated in a powder curing oven, typically to 375°F for about 10 minutes, depending on the parts’ thickness. A lot like cookies, the thicker they are, the longer they need to bake in order to reach the proper internal temperature. As they heat, the powder coating goes through a chemical reaction, called crosslinking, melting and flowing together to create a strong bond to the part’s surface.
Once the parts have cooled, your manufacturer can package and ship them.
Ask your suppliers of powder-coated parts which spray method they’re using.
If their system is automated with wagglers, are they staffing the line with someone to check and spray parts in missed spots?
Popular Metals to Powder Coat
Powder coating has become ubiquitous wherever parts have traditionally been painted. Any metal that holds an electrostatic charge and tolerates high temperatures is fair game for powder coating – that includes:
- Steel alloys
- Stainless steel
- Electroplated steel
Roll Formed Parts Best Suited for Powder Coating Include:
Goodbye Gray: Advantages of Powder Coating Roll Formed Parts
Powder coated steel parts and components add visual flare – and a few other benefits – to your projects. Manufacturers often choose to powder coat their roll formed parts for a host of benefits, including:
The #1 reason for powder coating parts, especially steel, is to protect against wear, tear, and corrosion.
Because powder coat forms such a strong bond to metal surfaces, it holds up better than liquid coating options to:
- Dents & dings
Manufacturers have several testing methods to verify the durability of a powder coating.
|Pencil Hardness||AKA the Wolff-Wilborn test; checks a powder coat’s hardness using different graphite pencils. Results are based on the lowest hardness value of the pencil that marks the powder coating.|
|Solvent Rub||Tests chemical resistance by rubbing a solvent-soaked cloth across a powder coated surface.|
|Salt Spray||Artificially ages a powder coated component in a pressurized chamber with salt and water to test corrosion and weather resistance.|
Several types of powder coating materials are available to match different application environments:
- Thermoplastics – melt at high temperatures and are recyclable. They’re smoother, more flexible, and tend to hold up well to chemical exposure.
- Thermosets – create an irreversible chemical bond and aren’t recyclable, but the bond allows them to withstand high temperatures. They’re ideal for electronics and appliances.
All in all, there’s a powder coat type on the market for basically every part’s intended use, whether it’s indoor, outdoor, high temperature, or high traffic.
The overall aesthetic of a good powder coat finish is the #2 reason, behind durability, purchasers choose to have their parts powder coated.
Finishes can be made to match any color very precisely, using the L*a*b* scale.
They’re also available in different gloss levels:
Common textures include:
There’s even clear options so powder coated parts can stay gray, if that’s your preference.
Note: It’s possible to galvanize steel and then powder coat it for extra durability and performance.
Compared to other finishes, powder coating is highly flexible (especially thermoplastics). This makes it a great choice for parts exposed to bending or vibration.
Just as with durability, manufacturers have several methods to test coating flexibility:
- Slow deformation – bending the part to test the coat for cracking
- Fast deformation – directly smashing the part’s coat or the non-coated, or reverse side, to test impact resistance
All this testing ensures a part receives the right powder coat type for its application. If a part is more flexible than its finish and the coating cracks, the part could prematurely corrode.
The whole powder coating process, from prepped to coated, cured, cooled, and ready to pack, takes only minutes.
Powder coating is by far more time efficient than liquid coating, which requires multiple coats and long dry times.
While it’s initially more expensive than liquid coating, or even galvanizing, choosing to powder coat is an investment in long-term savings during the life of a part. The process’s advantages make up for the up-front higher cost.
Metal manufacturers that offer powder coating have the option to either “spray to waste” and throw out over-sprayed powder, or reclaim it to reuse it, lowering the overall cost.
The fast turnaround time means parts spend less time in inventory, thus saving money – another win.
And, in a matchup between powder coated steel and stainless steel, coating is the more cost-effective option for your anti-corrosion needs.
Since it’s a chemical process, powder coating adheres better than liquid coating. It leaves a physically clean finish without drips, and it cures fast so there’s no smudging.
They don’t contain solvents, so they emit little-to-no volatile organic compound (VOC) pollution into the atmosphere.
Following their cleanliness, powder coated materials are very “green” and have low environmental impact. They are non-toxic, and there are no special requirements for their disposal.
Remember the three R’s of sustainability:
- Reduce – It takes less powder than liquid to coat a part, so the amount of materials required is reduced.
- Reuse – Powder overspray may be retrieved and reused.
- Recycle – And, as powder coating suppliers make gains in technology, they’re improving the process of recycling powder coatings.
Industrial Powder Coating vs. Paint for Roll Formed Parts
Finishing is practically the last step in the manufacturing process – right before packaging. Yet choosing the right industrial finishing technique for your roll formed parts is just as important as the other decisions leading up to that point.
To Coat, or Not to Coat
First and foremost, not all roll formed parts require a coating. Depending on the part’s material and application, you may be better off foregoing coating altogether.
Two of the most economical industrial finishing options seem interchangeable, so how do you choose: powder coating vs. paint?
If you’re basing your material choice on corrosion resistance you’re probably looking at:
- Stainless steel
- Red metals (copper, brass, bronze)
These metals don’t always need a coating thanks to their natural corrosion resistance.
However, if you’re not making parts from the above materials, you most likely will need to give them a protective finish, even if it’s a clear coat.
The Pros & Cons of Powder Coating Vs. Painting
Powder coating has become the preferred technique for finishing metal parts since its adoption in the global manufacturing industry in the 1960s and ’70s. Meanwhile, cases still exist where spray painting is the preferred parts finishing method. Consider:
Spray Painting Cons
Since we’ve already covered the advantages of powder coating, let’s delve into why it was developed as an alternative to spray painting. The following list won’t cover all the problems with liquid-based painting, but it’s a start:
- Coatings aren’t durable – Spray-painted coatings are susceptible to wear and tear. They require touch-ups and full-on repainting much sooner and more often than powder coated parts.
- Long dry time – Spray painting requires several applications to achieve a nice, smooth finish – and between each coat you have to wait and let the pieces fully dry.
- Difficult to achieve even finish – Adding a second coating before the first is dry leads to bubbling, dripping, smearing, and smudging.
- Not environmentally friendly – Applying it releases toxic volatile organic compounds (VOCs) that are harmful to breathe. The vapors are also flammable.
OSHA has a lot to say about spray operations standards. Spray operations require proper area ventilation; personal eye, face, and respiratory protection; and precautionary measures to guard against fires.
Because they’re toxic, there are also federal and state laws regulating the disposal of liquid paints. Unlike powder coating, liquid paints can’t be collected for reuse after they’ve been sprayed.
- MESSY – Vaporized paint droplets go everywhere. Powder coat particles, on the other hand, only stick to parts based on electrostatic charge.
Industrial Paints & Coatings: Types of Metal Finishes
Metal finishes are a critical component of many industrial applications, serving to protect your industrial parts’ surface from corrosion and wear over time.
Along with powder coating and painting, there are several other types of metal finishes available for use in different situations. Here we’ll specifically look at the disadvantages of each:
An electrically-applied wet process where metal parts are dipped in a bath of paint, then cured in an oven
- Thinner and less durable than powder coating
- Typically not UV-stable, thus preferred for undercoating, especially in the automotive industry
- Usually only available in black or white
A hot-dip method where the part is submerged in molten zinc heated to 860-900 °F (460-480 °C); forms a uniform layer on the part.
- Weakness to high temperatures and moisture; zinc layer becomes brittle and porous
- More expensive than its finishing competitors
An electrochemical treatment immersing a part in a chemical bath and applying a direct current to the surface creating an oxide layer on the part’s surface.
- Parts can be easily scratched or damaged if not treated properly
- More expensive than some other types of finishes due to the specialized equipment and chemicals required to complete the process
Often combined with other types of finishes, such as painting or anodizing.
- Electroplating – part is placed in an electrolytic solution, with a negative charge applied to the part and positive charge applied to the metal being deposited
- Electroless plating – relies on the auto-catalytic reduction process of metal ions in an aqueous solution containing a chemical reducing agent
- Surfaces can be easily scratched or damaged due to the thin layer of metal applied
- May not be suitable for outdoor applications due to their limited resistance to UV rays
Removes surface imperfections and improves appearance; usually an aesthetic choice useful for parts already in use, removing oxidation and preventing further deterioration.
Ways to polish parts include:
- Mechanical polishing using abrasives
- Chemical polishing with acids or alkalis
- Time-consuming process depending on the size and shape of the part
- Can remove too much material from the surface and cause distortion or damage
Can You Powder Coat Aluminum? And 14 Other Powder Coating FAQs
When it comes to powder coating, there are often many questions about the process and what it entails.
Let’s look into some of the most frequently asked questions about powder coating so you can make an informed decision about whether or not this is the right metal finishing choice for your roll formed parts:
Can You Powder Coat Aluminum?
Yes! Powder coating provides a protective and decorative layer that helps to extend the life of the aluminum surface and prevents it from becoming damaged or corroded.
What’s the Difference Between Powder Coating and Painting?
Powder coating provides an even, durable finish without dripping that can also protect the surface from potential damage and help resist rust.
Additionally, powder coatings are usually more environmentally friendly than traditional wet paint methods since they don’t use solvents or hazardous materials during the application process.
Painting relies on liquid coatings instead of powders which require drying times as well as multiple applications for a thicker finish.
How Long Does Powder Coat Last?
The typical life of a properly applied powder coating is 15-20 years. Generally speaking, powder coatings are known to be resistant to damage from scratches, abrasion, weathering, chipping, and fading – making them a great choice for outdoor metal parts.
What Types of Metal Work Best with Powder Coatings?
Steel and aluminum are the most popular choices for powder coating due to their relatively low cost and durability. However, there are other metals such as brass, copper, and stainless steel that can also be powder coated with great results.
Is It Necessary To Prepare the Part’s Surface Before Applying Powder Coating?
Yes, parts prep is extremely necessary! Skipping it can lead to poor adhesion or other issues with your finished product.
Surface preparation should include cleaning the substrate to remove any contaminants and fully drying it before applying powder coat.
Can You Apply Clear Topcoat to Protect a Colored Powder Coating Finish?
Yes, clear topcoats are typically applied as a liquid or powder, and the type used will depend on your desired outcome. Liquid clear coats generally offer more UV protection than powder coatings, but they may require more time to apply and cure.
Clear powder coating finishes are also available when you want your parts to show off their natural colors.
What’s the Cost of Powder Coating?
Powder coating cost varies depending on the type and quality of materials used, as well as the size and complexity of your project.
It’s less expensive and quicker than plating and galvanizing. Compared to liquid paint, it’s more expensive but quicker and easier to apply.
It’s important to keep in mind that powder coatings are more durable and longer-lasting than traditional wet paint applications, so the added cost can often be worth it in the long run.
Are There Any Environmental Benefits Associated With Using Powder Coatings Vs. Liquid Paints/Coats?
Yes! Powder coatings don’t use solvents or hazardous materials during the application process, making them much more environmentally friendly than traditional wet paint methods.
And, since powder coating can be applied in a single layer without dripping, it requires less material and energy to apply than traditional painting methods.
Finally, because powder coatings provide an even and durable finish that resists rusting and fading, they have longer lifespans than other types of finishes which means fewer replacements over time – leading to fewer resources used for production.
Does Humidity Or Temperature Affect The Application Process For A Powdered Metal Finish?
Humidity and temperature can have a significant effect on the application process for a powdered metal finish.
When the relative humidity is too high, the powder coating may not be able to adhere properly, resulting in an uneven finish.
Similarly, when the temperature is too low, the powder particles won’t be able to bond together as quickly or easily, leading to a weaker finish.
Therefore, it’s important to carefully monitor the humidity and temperature levels during the application process in order to ensure that you’re getting the best possible results.
Does Powder Coating Require Any Special Equipment or Tools?
Powder coating requires certain specialized equipment, tools, and processes in order to achieve an even and durable finish:
- A line system to move the parts
- A cleaning process to prepare them
- A spray system to apply the powder coat
- An oven for curing the powder coating
- Other tools such as safety gear and media blasting equipment
Additionally, it’s important to use high-quality powder coatings that are specifically designed for application on metal surfaces in order to ensure a long-lasting and attractive finish.
What Colors & Textures are Available?
Powder coatings come in a wide variety of colors and textures to suit most project needs.
Finishes can be made to match any color very precisely, and there’s even clear options so powder coated steel can stay gray, if that’s your preference.
How Thick is Powder Coating on Parts?
Powder coating on parts is about 1-3 mm when it’s applied. It thins as it cures to about 1-2 mm.
How Long Does Powder Coating Take?
The actual powder coating is quick – taking only seconds. The overall turnaround time depends on how much conveyor is on the powder coating line and how many parts are being finished.
The whole process, from prepping parts, to spraying, to curing, is about 40 minutes.
Does Dahlstrom Powder Coat In-House?
Yes! We powder coat your roll formed parts in-house, offering you time and cost savings by keeping your parts manufacturing process all under one roof.
Parts Manufacturing: At the End of the Line
You’ve put a lot of thought and effort into your part’s use, design, and production. Finish the job strong by choosing the right industrial coating based on your part’s unique characteristics.
Depending on the application, some types of finishes may be more suitable than others. Keep in mind the part’s:
- Metal properties
- Useful life
- The finish’s cost-effectiveness
Ultimately, by taking all these factors into consideration when selecting a metal finish for your products or projects, you can be sure you’ve selected the best option for your needs. Because of its versatility, durability, and cost-effectiveness, we recommend powder coating.
Powder Coating Industrial Parts with Your Roll Former
If you want a one-stop solution for forming and finishing your parts, look no further. Dahlstrom Roll Form has the engineering, manufacturing, and finishing expertise to take your OEM parts from the drawing board to the bay doors all under one roof.
Let’s talk about your custom roll forming and powder coating needs. Book a meeting with us: