The Three P’s of Powder Coating
Powder coating is the cornerstone of colouring technology in the manufacturing world, thanks to its extreme versatility, exceptional coverage and ease of application. Everything from cars, trains and planes through to tables, chairs and lamps can benefit from powder coating and the three P’s of powder coating will explain exactly how!
Precision
Unlike traditional paint jobs, powder coating takes advantage of an extremely technical application process. Rather than swiping the paint from a brush onto a piece of metal, powder coated items are first treated to an electrostatic treatment which makes the metal positively charged. The powder is sprayed through an electrostatic spray gun which gives the particles a negative charge, making the two attracted to one another and forging a bond that is hard to unstick. This allows for precision accuracy during the application process, resulting in better more even coverage.
Performance
Another benefit of the aforementioned technical application is that powder coating creates a hard shell on the outside of the product rather than a soft one like paint would. This makes the colour extremely hardwearing and gives the material an added layer of resistance. Compared to paint which can chip or scuff fairly easily, powder coating is much more robust and less susceptible to erosion, meaning a long-lasting colour job that is unlikely to wear or tear or have a reduction in colour saturation.
Protection
Thanks to this strong outer coating that powder coating provides, products are better protected than they would be if left untreated or painted. Not only does this help to elongate the lifetime of the product but also makes it of higher quality generally. A bonus of choosing to powder coat items is that the powder contains no harmful chemicals or solvents, unlike paint and so businesses will be helping to protect their product, their customers and the environment.
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Tips for Powder Coating Maintenance
Although powder coating stands up time and time against wet paint applications, it still requires some care and maintenance to keep it in the best possible shape. Just how much attention a powder coated product requires will differ based on where the product spends the majority of time, the contaminants it encounters and the use of the product. Read on for tips and information on keeping your powder coated products in the best condition.
Limit Cleanings
Of course, everything requires cleaning but with a powder coated item, too much cleaning can cause excessive wear and premature erosion. In most cases, one clean at the start of each new season will be sufficient, focusing on all the hard to reach areas and nooks and crannies. In between these deeper cleans, a quick spray with antibacterial and wipe with a soft cloth will be sufficient enough to remove germs and dirt without affecting the coverage.
Use Gentle Agents
Whenever you do clean a powder coated item, it’s important to use a mild cleaning agent that isn’t overly acidic. Something like bleach for example, can chemically erode the powder, even if applied with a soft cloth and limited pressure is used. Instead, opt for something less intense in a soap format and try to avoid any cleaning agents with abrasives added to them.
Apply Protection
If your powder coated item is designed for use in high contact areas, you can protect them by applying a high-quality car wax to provide a barrier between high touch surfaces and the product. Like with a car, simply apply every three months, ensuring you get an even coverage. For outdoor items, opt for a wax that provides protection from UV rays to avoid fading.
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Powder Coating Process
The Process
What is Powder Coating?
Powder coating is a dry finishing method that has become hugely popular since its introduction in America in the 1960s. It now serves over 15% of the manufacturing finishing market and is used on an extremely wide array of items. More and more businesses are shifting to powder coating because of its high-quality, durable finish, maximised production, improved efficiencies and low environmental impact. Used for both embellishing and practical finishes, powder coatings variety of colours, textures and technological advancements have resulted in flawlessly performing items.
How Powder Coating Works
The Powder
Powder coatings are comprised of polymer resin systems, combined with curatives, pigments, levelling agents, flow moderators and other additives. These are mixed, cooled, and ground into a fine powder with a similar texture to flour.
Pre Application
Before an item can undergo the powder application it must first be treated to remove any debris and rust on the surface. At Finishing First UK Ltd, we use a phosphate wash, this effectively removes anything from the exterior whilst neutralising the PH and priming the metal for the powder.
The Application
A process called electrostatic spray deposition (ESD) is used to adhere the powder to the metal substrate. This uses a spray gun, which applies an electrostatic charge to the powder particles, which are then attracted to the grounded surface of the metal.
Curing
Once the powder has been applied, the item then undergoes the curing process. This is where the addition of heat causes the coating to ‘melt’ and chemically react to produce long molecular chains, resulting in high cross-link density. These chains are resistant to breakdown, which is what makes powder coated products so durable.
The Benefits of Powder Coating
Compared to traditional wet paint methods, powder coating can offer incredible benefits for the item:
Durable
Powder coating is resistant to chips, dings, corrosion and abrasions.
Versatile Applications
Can withstand extreme weather conditions and harsh environments and is used in a wide variety of industries.
Environmentally Friendly
Powder coating releases less hazardous waste and harmful gases (VOCs) into the atmosphere, and with our state of the art paint recycling feature, the paint overflow is reduced and our waste is drastically minimised.
Time Efficient
Without having to wait days for the paint to dry, items that are powder coated are ready to go immediately after the curing process.
To find out more about how we use this process to provide clients with exceptionally high-quality finished items, contact our team here.
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Does Stainless Steel Rust?
Stainless steel is a well-known corrosion-resistant alloy and with good reason. However, there are some cases where it seems that the stainless steel rusts. Was it actually stainless steel, or was this part manufactured from an inferior metal? Let’s find out.
Is Stainless Steel Rust Proof?
Stainless steel is highly corrosion-resistant, but it can rust under highly corrosive conditions. Stainless steel kitchenware is unlikely to rust when you use it only for cooking; clean it immediately afterward, and store it away from heat and humidity.
In jewelry, prolonged exposure to sweat and the oils in your skin might cause items to tarnish or rust if they also get nicked and dented. Here, it’s also essential to clean it regularly.
Why Stainless Steel Doesn’t Rust?
Well, it all has to do with the composition of the metal. Stainless steel is an alloy that is made up of iron and carbon with a few other trace elements mixed in. It’s this mixture that keeps stainless steel from rusting, as opposed to unprotected metals like wrought iron or mild steel.
To understand how stainless steel works, let me briefly explain to you the composition of this alloy.
What is stainless steel?
Stainless steel is a ferrous alloy of iron with carbon, copper, and chromium as its primary alloying materials. However, nickel and other trace elements could also be added. The chromium content in stainless steel is at least 11% but can be higher.
As the name suggests, stainless steel is resistant to stains in the form of rust and corrosion. This alloy is also completely recyclable and can be recovered entirely from construction sites. This durable metal doesn’t leak components when in contact with water. Thus its composition and physical attributes don’t change in wet environments.
Stainless steel is most often used in environments where high levels of hygiene are imperative, such as culinary and surgical applications.
What keeps stainless steel from rusting?
In short, it’s the high chrome content that keeps stainless steel from rusting. Here’s how that works:
Usually, steel and other ferrous alloys (metals containing iron) rust or corrode when they contact oxygen and moisture. In the case of stainless steel, chromium is more reactive than the other alloying elements. When in contact with oxygen, chromium reacts to form chromium oxide and an inert layer on the item’s surface. This layer acts as a protective barrier, preventing oxygen from reaching the alloy underneath.
When stainless steel gets scratched, nicked, or dented, this protective chromium oxide layer gets damaged, allowing oxygen to reach the layers underneath. Here, the protective chromium oxide layer gets restored again through another round of reactions with oxygen. In this sense, stainless steel is self-healing.
As you can see it is the alloying element that changes the property of the steel including the magnetic property of stainless steel.
To prevent stainless steel from rusting under normal usage conditions, it’s a good idea to clean it regularly. Wiping it down with mild detergent and a clean cloth would suffice. Be sure to dry it properly afterward. Scrubbing stainless steel with steel wool or steel wire could cause rust formation – more in this in the next section.
What grade of stainless steel will not rust?
Surgical-grade stainless steel is the most corrosion-resistant version of this alloy. This is 316 stainless steel, the second most commonly used stainless steel on the market. The most popular form of stainless steel is 304 stainless steel. These two alloys are identical, except that 316 stainless steel contains molybdenum, enhancing its corrosion resistance. This form of stainless steel is suitable for use in marine and chloride-exposed environments, where the risk of corrosion is highest.
What Can Cause Stainless Steel to Rust?
Exposure to highly corrosive environments, such as seawater and other harsh chemicals, can cause stainless steel to rust. There are also cases where stainless steel rusts seemingly in the absence of these environments. Here’s why:
When the local chromium content in stainless steel is high enough to counteract the corrosive environment (i.e., greater than 11%), the stainless steel will not rust. When you scrub down a kitchen sink with steel wool, steel particles break off and remain in the sink. If these aren’t cleaned off and the surface dried thoroughly, the localized raw steel content increases, diluting the chromium content. In effect, in the spots where this wire contacts the sink, you have pockets of non-stainless steel. This exposes the iron in the alloy to oxygen attack, leading to pockets of rust forming.
Rust is a reaction between oxygen and iron, forming iron oxide. Iron oxide is less dense than iron, so it expands and spalls off. Basically, there isn’t enough space for all the iron oxide molecules to remain where they’re formed. When these molecules spall off, they expose a new layer of iron atoms to oxygen, in effect allowing the process to continue until some intervention occurs.
You can enhance the rust-resistant property by powder coating stainless steel that are exposed to harsh conditions.
How to Remove Rust from Stainless Steel?
It’s easy to clean rust off stainless steel and return the item to its pristine, stainless condition.
First, all the rust (iron oxide) should be cleaned off. Here, vigorous scrubbing with a wire brush would suffice. For small areas, you could use a sandpaper to remove the rust.
For larger areas, consider using a power tool like angle grinder with rust removal disc to get rid of stubborn rust.
Next, the area must be thoroughly cleaned to remove all traces of the rust-causing steel particles. A solvent wiped on with a clean cloth is usually the best method to go about this.
Finally keep your stainless steel jewelry, cookware, knifes, tools etc. clean and dry to stop is from rusting again.
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Can You Powder Coat Aluminum?
Powder coating is a widely used application, protecting metals from corrosion and improving their aesthetic appeal. Can aluminum be powder coated? Is it necessary since aluminum is already corrosion resistant?
Can Aluminum Be Powder Coated?
Yes, aluminum can be powder coated. Some manufacturers warn that the powder coating process could harm the metal’s integrity, but this depends on the powder coating methods being used. When carried out correctly, powder coating will not harm aluminum, and the resultant finish will improve the part’s corrosion resistance, wear resistance, and aesthetic properties.
Why Powder Coat Aluminum?
Aluminum is a lightweight metal widely used in both aesthetic and functional applications. While aluminum is naturally corrosion-resistant, some applications call for additional corrosion protection, achieved through powder coating. This process could also improve the metal’s wear resistance, change the color and surface finish, and create a reflective surface.
Aluminum Powder Coating Process
The powder coating process consists of three main parts: pretreatment, powder application, and curing. In this section, we break down each step and analyse essential factors that should be considered.
Pretreatment
During pretreatment, the part to be coated is cleaned in several stages to remove all dirt, grime, and impurities from the surface. This is an essential step since impurities could negatively affect the powder’s adhesion to the surface, ruining the outcome.
Power Washing
When encountering oxygen, a thin layer of aluminum oxide forms on the metal’s surface. For effective powder coating, this layer must be removed through power washing. This exposes the pure metal surface to be coated.
Aqueous Alkaline Cleaning
Next, the part would undergo aqueous alkaline cleaning. Here, the aluminum part is dipped in a solution containing between 2 and 5% sodium compounds. For effective cleaning, a soft-bristle brush is used to gently brush the surface, removing any impurities. This brush should have nylon bristles, not copper or steel since that could damage the surface.
Following this scrubbing, the part is rinsed using warm water or water under pressure. Next, it is dried thoroughly, preferably in a heated environment, ensuring that all excess water is removed from the surface.
Solvent Cleaning
Solvent cleaning follows, removing grease and oil from the part’s surface. Here, mineral spirits or similar cleaning chemicals are applied to the part using clean rags. Once properly wiped down, the part is rinsed again, using hot water or water under pressure, as before. The part is then dried in a heated environment, ensuring completely dry before commencing the next step.
Hand Cleaning
If any obvious dirt remains on the part, it can be cleaned by hand or by using a power tool. Again, the part should be rinsed and thoroughly dried before carrying out the next step.
Surface Preparation
Here, any remaining aluminum oxide is removed from the metal’s surface, and the surface is roughened to improve powder adhesion. To this end, one of two methods is generally used: sweep blasting and phosphate treatment.
Sweep Blasting
During sweep blasting, pressurized air is used to blast abrasive media at the metal’s surface. Aluminum or magnesium silicates are generally used, although various other abrasive media could be used.
Phosphate Treatment
During phosphate treatment, a phosphate solution is applied to the metal’s surface. This can be done through complete immersion, surface spraying, or soft bristle application. Aluminum reacts with this solution, converting the surface into crystalline phosphate coating, which improves powder coating adherence. The process requires between three and six minutes, after which the surface should be thoroughly rinsed with water and dried again. Powder coating should take place immediately after this to prevent any new dirt from attaching to the surface.
Powder Application
During powder coating, electrostatically charges powder particles are flung at the metal’s surface. The aluminum part to be coated is electrostatically grounded. This difference in charge creates attraction between the powder particles and the metal’s surface, allowing them to stick to the surface.
Curing
Once the desired coating thickness is achieved, curing takes place. Here, the part is heated to the desired curing temperature, usually between 350 and 400֯F (176 – 205֯C) for around 10 to 20 minutes. The curing temperature and duration depend on the powder used and the coating thickness.
Coating Thickness on Aluminum
Powder coating varies in thickness depending on the application. Smooth surface layers of between 2 and 4mm are typical. When applying powder coating layers thicker than this, you risk orange peel and pockmark effects. While this is generally not desired, some applications warrant this aesthetic sacrifice, given the extra coating thickness achieved.
Aluminum Powder Coating Colors
Powder coating is available in any color imaginable and in a variety of finishes. These include matt, gloss, satin, high-gloss, super matt, and textured. With the latest technological advances, color gradients are also available.
Does Powder Coating Weaken Aluminum?
While powder coating in itself doesn’t weaken aluminum, some pretreatment processes could. Sweep blasting, or sandblasting, could damage the metal’s surface, especially if the part in question is fragile. Some worry that the heat necessary for curing could damage the metal since aluminum anneals at far lower temperatures than stainless steel. This is unlikely, though, since aluminum anneals at 650֯F (343֯C), and powder coating curing generally requires a maximum of 400֯F (204֯C).
Powder Coating Aluminum vs. Anodising
Anodising is an electrochemical process used to improve aluminum’s corrosion resistance. To this end, it increases the aluminum oxide surface layer’s thickness. Anodised parts are easy to maintain through periodic cleaning with water and mild detergent.
Unlike other surface coatings, the anodised layer won’t peel or flake since it’s part of the metal and not just a coating. It is also impervious to sunlight and will thus not fade over time. However, the anodised layer is vulnerable to attack from acidic pollutants, common in urban areas.
Anodised coatings are translucent and are thus limited to matt or gloss finishes with no intended color variation. However, these finishes often vary in color between batches, causing unwanted color variation in architectural projects.
Powder coatings are available in various colors and finishes and are highly consistent between batches. Maintenance is simple – since powder coating is chemically resistant, it can be cleaned using industrial-grade chemicals. Dents and scuffs are also easily repaired using a liquid repair agent.
Both powder coating and anodising call for correct application. When misapplied, both methods are likely to produce poor surface finishes, with typical streaking and orange peel effect.
Aluminum Powder Coating vs. Paint
Powder coating and painting are the most commonly used surface protection for aluminum. Both are available in a variety of colors and finishes, and both are easily applied. That is where the similarity ends, however.
Powder coating is far thicker than paint. This means that powder coating offers more protection against environmental factors than paint does. It also has greater surface adhesion than paint, making it less likely to chip or flake.
Paint is inflexible. When the metal it’s painted onto vibrates or moves, tiny cracks form in the paint’s surface. This leads to chipping and flaking. Conversely, powder coating is flexible, allowing it to move with the metal. This flexibility makes it far less likely to chip or flake.
Powder coating’s flexibility allows it to absorb surface impacts, such as scratches, nicks, and dents, making it far more hard-wearing than paint.
Some types of paint offer a measure of corrosion resistance, but powder coating is inherently corrosion resistant. Here, again, it offers greater protection than paint.
Is It Better to Powder Coat or Paint Aluminum?
Powder coating outperforms paint in all aspects of surface protection. Since it is more hard-wearing and less likely to chip or flake, it also calls for far less maintenance and reapplication than paint.
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What is Powder Coating? Process & Uses
Powder coating revolutionised architecture, furniture manufacturing, and outdoor metal maintenance. This versatile coating protects metals and other materials from corrosion, dents, and scratches while elevating the surface finish. How does it work, though?
What is Powder Coating?
Powder coating is a surface treatment used to protect metals and other materials against potentially harmful environmental factors. This coating is applied electrostatically as a free-flowing powder and cured under heat or UV light. It can be applied to any material, but it is commonly used on steel, aluminum, and plastic.
Powder coating differs from traditional liquid paint, which is generally applied using an evaporating solvent. Though it is not as durable as Physical Vapor Deposition (PVD) coating due to its thickness, it provides excellent rust prevention, color uniformity and scratch protection.
Why Use Powder Coating?
Metals tend to corrode under normal usage conditions. Even stainless steel can rust under specific conditions. Here, it is helpful to apply a protective surface layer that is corrosion resistant and tough enough to withstand expected wear that the part in question may undergo.
Powder coating is a commonly used surface coating since it is tough, can vary in thickness, and comes in various colors and surface finishes. Areas where powder coating is advantageous include marine applications and roadways where de-icing salts are commonly applied.
Non-metallic materials sometimes require a protective surface layer too. These include plastics, carbon fiber, composites, and MDF (medium-density fiberboard). Here, the surface coating will usually protect the part in question from the sun or other harmful environmental factors.
How Does Powder Coating Work?
Powder coating is divided into three categories: thermoset, thermoplastic, and UV curable. While these categories differ in application and execution, they all have this in common: a powder is applied to a surface, which hardens under specific conditions. This creates an even, corrosion-resistant surface coat.
Types of Powder Coating
The three main types are,
- Thermoset
- Thermoplastic and
- UV Curable Coatings
Thermoset
Thermoset powder coating is most commonly used since it is generally the least expensive option and easy to apply. Thermoplastic powder coating is usually more expensive, although recent technological advancements enabled enormous cost reduction in the process.
Thermoplastic
Thermoplastic coating offers higher performance than thermoset. It is also less dense than thermoset powders. Thus you can use far less powder to achieve the same finish. Thermoplastic powders are also thicker and more flexible than thermoset powders. Here, thermoset powders, which are harder than their thermoplastic counterpart, offer greater scratch resistance. Conversely, thermoplastic powders offer greater impact resistance due to their superior flexibility, although these are less resistant to scratches.
Thermoplastic powders can be recycled since they become liquid again when reheated. Unfortunately, thermoset powders cannot be recycled since their set is final after the initial curing process.
UV curable
UV curable powder coating is similar to thermoplastic coating, except it cures under UV light instead of at high temperatures. The advantages here are legion. Since this process doesn’t require high temperatures, heat-sensitive materials such as wood and organic fibers can also be powder coated. The decreased heat requirements also translate into economic savings since you no longer require an oven on-site, reducing space and energy costs. UV powder coating also cures faster than the heat-sensitive thermoset and thermoplastic powders, decreasing turnaround times.
Each powder coating category has specific strengths and weaknesses. Thus the requirements of each application will determine the one best suited to that situation.
Powder Coating Process
The powder coating process requires three basic steps, regardless of the type of powder used: preparation, or pre-treatment, application, and curing. Here is an overview of each step.
Preparation
Preparation is essential for successful powder coating. All dirt, oil, and debris get cleaned off the part in question since these could hinder powder adhesion in later steps. This preparation step could consist of several steps in itself, depending on the material in question and the initial state of the part. The first step is generally physical cleaning, where the part is scrubbed, sand-blasted, or washed using a high-pressure spray. This reliably removes most of the physical dirt that could be present on the part.
Often, metallic parts are chemically treated in processes called phosphating and chromating. Here, the metals are dipped in corrosive acids for a predetermined, concise time, after which they’re rinsed and dipped in phosphate or chromate solutions. This improves the subsequent bond between the metal and powder, improving the surface finish and product performance. The phosphate and chromate solutions used aren’t environmentally friendly. For this reason, many coating services have replaced them with titanium zirconium silanes, which offer similar corrosion resistance and powder adhesion properties.
Heat-sensitive plastics and composite materials are often hydrophobic, have a low degree of wettability, and have low-energy surfaces. These aspects all negatively affect powder adhesion during the powder coating process. These materials undergo plasma treatment to overcome this challenge, which creates chemically active binding sites on the material’s surface. Now, this surface is wettable and hydrophilic, providing ideal conditions for powder adhesion.
Application
Powder application varies slightly depending on the material being coated. Generally, one of three application methods is used: electrostatic gun, electrostatic fluidized bed, or electrostatic, magnetic brush.
Electrostatic Gun
When powder coating metal objects, the powder is usually sprayed onto the object using an electrostatic gun, also called a corona gun, after the most common nozzle configuration. Here, the metal part is electrically grounded, while the spray nozzle imparts a negative electrostatic charge to the powder particles. The particles are shot towards the metal, either mechanically or through compressed air. Once airborne, they’re accelerated by the electrostatic attraction between the negatively charged particles and grounded metallic surface.
Various spray nozzle configurations are available, each suited to coating specific object shapes. This variety enables precise coating practices, minimising waste and optimising surface finish.
After coating, curing takes place – this is most commonly achieved through high heat. In some cases, the metallic part is heated before powder application. Here, the powder melts onto the surface, achieving a more uniform surface finish. When too much powder is applied in this manner, the powder could run down the surface, ironically creating a poor surface finish.
Electrostatic Fluidised Bed
A fluidised bed is essentially a tub of powder with air flowing through it. Aerated powder behaves like a fluid, which allows parts to be dipped into it. In a conventional fluidised bed, this part would be metallic and heated. When dipped into the bed, the powder melts and sticks to the part, after which conventional curing would take place.
An electrostatic fluidised bed is similar to a conventional fluidised bed, but it has more powder depth and an electrostatic charging medium added to the bed. This creates a cloud of electrostatically charged particles floating above the bed. The metallic part to be coated is grounded and passed through this cloud, causing the negatively charged particles to stick to its surface. This is followed by curing.
Electrostatic Magnetic Brush
Electrostatic magnetic brush, or EBM, coating is relatively new and works on similar principles as a copier machine. Here, the powder is applied to a flat surface using a roller. This application is highly accurate, allowing layer thicknesses between 5 and 100 micrometers, applied efficiently at great speed.
Curing
Curing differs depending on the type of powder used. Thermoplastic and thermoset powders both require heat to cure. Here, each powder requires exposure to a specific temperature for a set amount of time to attain the desired properties. Traditionally, thermoplastic powders were cured at 200֯C (390֯F) for ten minutes. Recently, a low-bake approach enabled adequate curing at 160֯C (320֯F) for ten minutes, decreasing production costs and rendering the process more environmentally friendly.
Since the low-bake approach necessitates the use of catalysts to ensure proper curing, they’re not as color-stable as their high-temperature cured counterparts.
UV, or ultraviolet, curing still requires heat for proper curing, but at far lower temperatures than thermoplastics and thermosets. UV powder coating curing times are far shorter than their traditional counterparts, requiring only one or two minutes at 110-130֯C (230-266֯F). UV powder coating applications use UV LED curing systems, which are more environmentally friendly than conventional curing ovens. Their high energy efficiency, paired with the low-temperature requirements and fast curing times of UV-cured powders, decrease production costs considerably compared to thermoplastic and thermoset applications.
Powder Coating Gun
Typically, powder coating applications use one of two powder coating guns: the tribo gun or the electrostatic gun, also known as the corona gun. The corona gun is most commonly used and works on imparting a negative electrostatic charge to the powder particles. After receiving the charge, these particles are shot at the part to be coated through compressed air or mechanical action.
The corona gun has various nozzle configurations, enabling the user to easily coat surfaces in multiple configurations in any orientation. A downside of using the corona gun is its affinity for back ionisation and the Faraday cage effect. Here, the charged powder particle fails to find a ground point on the surface to be coated and thus builds onto particles already stuck to the surface. This causes uneven coverage in what’s called the “orange peel effect.”
The tribo gun imparts a positive electrostatic charge to the powder particles through triboelectric friction. Here, the powder particles move through a Teflon tube inside the gun. Friction with this surface imparts the charge, which then causes the particles to be attracted to the grounded metal object to be coated. While the tribo gun requires a different powder type to the corona gun, it doesn’t suffer from the same weaknesses (back ionisation and the Faraday cage effect).
Benefits of Powder Coating
Powder coating provides better corrosion resistance, longer life, and better appearance than the traditional liquid-coating method. Here are some of the benefits of powder coating.
Rust Prevention
Powder coating is an excellent method to protect the steel pieces from rust. The coated layer prevents the atmosphere from coming into contact with the steel and eliminates the possibility of oxidisation. You can also coat metals such as brass, copper, bronze etc. to prevent them from oxidation. You can even powder coat stainless steel to enhance the rust resistance of the metal alloy.
Tougher Than Paint
Powder coating offers a tougher layer than conventional paint, rendering it more hard-wearing and thus suitable for a greater range of applications. This hard-wearing aspect also prolongs the surface coating’s useful lifespan compared to conventional paint. Powder coating layers can be thicker than paint since they won’t sag or run, adding to their toughness.
High-Quality Surface Finish
Paint is liable to the formation of pinholes. These tiny air bubbles burst as the paint dries, leaving tiny holes in the surface finish. Here, corrosive substances gain access to the material underneath, causing long-term damage and negating the protection offered by the paint. Since powder coating isn’t applied using a brush, there are no pinholes or other surface blemishes. This enhanced quality in the surface finish offers greater protection to the finished product.
Additionally, parts can be powder coated in any orientation since there is no difference between parts coated horizontally or vertically. This is opposed to traditional paint, where the orientation plays a vital role in the subsequent surface finish.
Wide Aesthetic Range
Powder coating comes in various colors and surface finishes. It is thus suitable for a wide range of architectural and aesthetic applications. This allows for designs that incorporate the structural strength of metals, paired with the aesthetic finish of any color and texture.
Various powder colors can be applied in a single layer and cured together, allowing for color blending and bleeding. These special effects are often hard to achieve using traditional paints.
No Volatile Compounds
Powder coating is just that – powder. There are no carrier liquids and thus no volatile organic compounds (VOC) that will evaporate during curing. This renders powder coating safer than traditional paint.
Recycling the Overspray
When applying powder coating or traditional paint using a spray gun, a large amount of material is likely wasted as “overspray.” This refers to the portion of material dispensed from the spray gun that never reaches the intended surface. In the case of traditional paint, this is wasted. However, in powder coating applications, this overspray can be collected and recycled, saving material and minimising waste.
Note that when various colors are mixed and applied to the same surface, the overspray may not be viable for recycling since the color balance will be incorrect.
Fast Curing Time
The curing time for powder coating is far shorter than that required for traditional paint. This is especially true in applications using UV curing or advanced low-bake thermosetting powders.
Disadvantages
Limited by Heat Curing
Powder coating applications that require heat curing can only be used on certain materials, mainly metals. The high temperatures required in this process rule out most polymers, composites, and MDF (medium-density fiberboard), since these materials aren’t heat resistant.
Thin Layers Don’t Always Cure Well.
While thick layers of powder coating cure smoothly and are easily applied, thin layers can be challenging. Since the powder’s particle size is quite large, thin layers often show the orange peel effect. Many applications call for a smooth surface finish, although the orange peel effect is desirable in some applications. This effect hides metal defects and renders the finished surface less prone to showing fingerprints, both of which are desirable in specific applications.
Powder Coating Has A Large Capital Outlay
Purchasing and maintaining the equipment needed for powder coating is expensive and often prohibitive. This is far more expensive than traditional paint, for which you only need a paintbrush and cleaning products.
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Want to see some of our recently completed projects including photos of the finished items? Click the button below to be take to our powder coating and wet paint specialist portfolio.
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