Powder Coating vs. Spray Painting

If you’ve worked in the metal fabrication industry dealing in appliances, aircraft, or vehicle assembly, you’d be familiar with the two most common methods for applying color finish to metal surfaces – powder coating and spray painting. 

The debate of powder coating vs. spray painting has raged on for some time now.

Some professionals swear by powder coating, citing critical key advantages like durability and resistance to degradation. The others insist that spray paint is versatile, dries faster, and is available in various color choices. 

That’s the focus of this article. We will do a spray paint vs. powder coating comparison, and hopefully, at the end of it, you’ll be able to choose the best metal finishing technique for your next project. 

What is Powder Coating, and How Does It Work?

Powder Coating is another method of applying a color finish to a surface, except that powder is used instead of paint.  

Whereas spray painting uses a sprayer and paint, the spray equipment used in powder coating is heated to the specific substrate to form a color coat. 

Powder coating comprises several ingredients: polyester, epoxy, acrylic, and polyurethane. Powder coating provides a thicker and more consistent finish than spray paint though it’s also available in spray cans that provide light-duty applications.

You may not know it, but you’ve probably encountered different household items and appliances with powder-coating finishes. 

These are everyday items like stoves, lamp vases, table lamps, refrigerators, and laundry machines. 

But powder coating process is generally applied in the automotive industry, especially on color-finished motor vehicles. 

Powder coating can be applied with thermoplastics or thermosets. Thermoplastic is a chemical-free process that uses heat to transform the powder into a thick, solid coat. 

Thermoset, conversely, is a chemical additive that interacts with the powder during the application to produce a solid coat. 

The outcomes of thermoplastic and thermoset powder coatings are pretty much the same. Both powder coating process require powder heating to achieve a color finish on a surface. 

What is Spray Painting, and How Does It Work?

Spray painting is the traditional, most common means of achieving a color finish on a surface. This process entails applying an aerosolized formula at high pressure using a pump or spraying device. 

The application techniques may differ slightly from one device to another (spray can, spray gun, or heavy-duty industrial sprayer). Still, in all cases, the result is a  consistent, even coat over a chosen surface.

Spray painting requires deliberate and adequate surface preparation before the paint can be applied. 

The surface should be cleaned thoroughly to remove any oils, dust, or old paint residues before it is treated to a wet blast of roughly 15-20 micrometers. 

The process involves various other steps like sanding and priming, pausing between each coat until s consistent, smooth finish is achieved. 

Advantages of Powder Coating Over Wet Spray Painting

So what makes powder coating great? How is it better than other color finish techniques, particularly spray paint? First, powder coats are more durable, meaning they’ll likely last longer on your surface than wet painting with spray cans or guns. 

Powder coating finishes are also more attractive and versatile, meaning they can be applied on nearly every surface and material. The benefits of powder coating are summarized below:

• Durability: Powder coating provides a thick attractive finish that lasts longer than ordinary coats of paint. In the powder vs. spray paint comparison, powder coating is the most durable. 

• Convenience and speed: With powder coating, you only need a single thick coat to achieve an efficient finish, while spray painting involves several steps and works best with thin coats.  

• Diversity: Powder coating allows you to create a unique finish by mixing and experimenting with powders of different colors before application. 

• Eco-friendliness: Unlike traditional paints, powder coats are not made with any toxic ingredients, and even if one of them does contain toxin wastes, they are not produced during application making this method friendly to the environment. 

• Consistency: Powder coating is more consistent because it does not drip, spread unevenly, or leave application marks on the surface. Also, with a bit of sanding, you can even paint over powder coats. 

Disadvantages Of Powder Coating

At this point, you could be thinking that powder coating is the most robust and flawless color application technique out there. This may be true, but powder coating does have a few drawbacks, as we can see below:

• Thick coats: Powder coating is best applied on metal surfaces, and even with that, you can only apply thick coats. In most cases, a single thick coat of dry powder is all you can apply. This may be limiting, and if you’re not a pro, achieving a smooth, flawless finish can be tricky. 

• Equipment requirements: The most significant disadvantage of using the powder coating technique in your project is the equipment requirements. Powder coating requires expensive, high-tech equipment like an industrial oven and an electrostatic booth beside the regular spray tools, and none of these are cost-effective. These requirements may not support DIY crafts and other smaller operations.  

• Color matching: It’s easy to mix liquid paint as you prepare to start your project, but the same cannot be said for powder coats because the colors are formulated with special production runs, which are then determined by the plastics used to make them. If you attempt to mix different colors while powder coating, you could end up with speckled patterns instead of a consistent color theme.  

• Minor surface limitations: Powder coating offers a durable and efficient finish on most surfaces like metal. However, despite its versatility, it’s not compatible with rubber surfaces that cannot withstand the electrostatic process and will melt instead. 

Advantages Of Spray painting

First, it was brushing, then rolling, and as the art of color finishing became more sophisticated, spray painting entered the scene, determined to give the two traditional methods a run for their money.

Now more and more people are into spray painting as brushing and rolling drop in popularity. So what makes spray painting more popular and preferable? 

• Self-drying. Spray paint is generally wet liquid paint. It dries independently, with no oven, no heaters, just a touch of nature. You can easily apply fine spray paint to materials or substrates that do not work with heat, such as rubber and fabric. 

• Color range. Paint can be applied in a wide range of colors, unlike powders. You can apply several colors simultaneously to create a perfect color combo, especially on signages and product assortments.

• Better texture: Spray paint works with thin coats, and thin coats of paint are known to create smooth, efficient finishes with good texture. This makes spray paint the ideal option for projects that require light touches.

• Affordability: Spray paint, along with the equipment and tools needed for the painting process, is relatively affordable, unlike powder coating, which is quite an investigation in itself. 

Disadvantages Of Spray painting

Just like powder coating, spray painting also has its share of weaknesses. For instance, spray painting lacks the same level of durability that powder coating provides. 

As time goes by, you’ll need to do some touch-ups to maintain your project, and in some cases, you’ll need to add a whole new coat of paint to revamp the surface. 

In addition, achieving an even coat with wet paint is tricky. It requires a delicate balancing act to maintain consistency with several thin layers of paint if you want a perfect project. 

You don’t endure such pains with powder coats which offer more efficient and durable coating with a single thick dry powder coat paint devoid of trace marks.

Spray Paint vs. Powder Coating: Which One Is Best?

Our spray painting vs. powder coating debate runs deeper.  

Having explored the strengths and weaknesses of these two paint application techniques, we now look at their overall features and performance on various materials and under different circumstances to try and determine which one should be used in different situations. 

 Cost Efficiency

You would think that spray painting is much cheaper compared to powder coats. After all, you only need spray paint and a piece of spraying equipment for this method. Besides, isn’t the average price of spray paint less than $50? That would make spray painting more efficient, right? Wrong. 

When economic factors are carefully considered, powder coating provides more efficiency. Yes, we mentioned that the process is costly, especially the equipment, which sometimes involves industrial machinery, making it unsuitable for small-scale projects. 

So what we mean by higher efficiency is that about 60–70%, or about two-thirds of the powder applied on the surface, actually lands on the substrate and serves the purpose intended. By comparison, paint, especially spray paint, can only produce a transfer efficiency of 30-35%, with nearly two-thirds of the paint sprayed going to waste. 

Even better is, with powder coats, the surplus that falls aside can be recycled and reused in the next powder coating services. This form of conservation cannot be achieved with spray paint which atomizes and dissolves in the air if it doesn’t land on the substrate. 

So while spray paint costs less than powder coat, the amount you’ll lose during the process sort of doubles up. The extra expense of powder coating may be worth it, but the decision depends on your project and your budget. 

Safety

Here’s yet another scenario where powder coating comes tops against spray paint. The process is much safer, thanks to the active ingredient, a polymer, which is largely inert and completely free of toxins. 

For spray paint, the main ingredients are toxic solvents and hazardous volatile organic compounds. You must always wear protective clothing and equipment while dealing with spray paint, while the same may not be necessary with powder coating. 

Powder coating is a much cleaner and safer process than spray painting though you should take care not to come into direct contact with the powder in case you develop a skin irritation or allergic reaction. 

In addition, spray paint is highly flammable and must be stored properly away from heat. If you cannot meet the storage demands required for spray paint, powder coating would be more preferable.

Environmental Factors

Unless you work with specialty paints indicating they are eco-friendly and free of toxins, this spray painting is generally unsafe. 

During application, the paint toxins and VOCs are released into the atmosphere and can cause health problems if inhaled. These concerns are non-existent with powder coating applications. 

The main ingredient in powder coating is a polymer that doesn’t contain any toxins, nor do you have to worry about unused portions emitting greenhouse gasses, especially those that end up in landfills.

Mechanical Convenience

Any professional automotive painter will tell you that greater strength and flexibility can be achieved with powder coating than in spray painting. Powder coats are more robust, thick, and durable. They’re not susceptible to scratches. They’re also more bendable and suitable for flexible items that change shape or those with moving parts. 

You can use powder coats on transportation equipment and general machinery. This color-finishing technology is also highly resistant to pebbles, flying debris, and other hazards that easily get thrown into moving vehicles. 

However, there are a few instances where the durable thick coats provided by powder coating may not be ideal. Such instances include adding color finish to specific items for aesthetic purposes,  not functionality. 

In such cases, you’ll need to work with thinner coats which are best achieved with spray paint. 

Productivity

Unlike spray paint which may take several hours or even days to cure fully, powder polymers take quite a short time to dry and cure on a surface. This is despite the technique of using only thick coats. Powder coating takes roughly 20-30 minutes to dry and cure before you can use the item. 

In addition, while you should wait for spray paint to cure before you can use your project, a powder-coated project can be used even before it cools from the oven. 

Powder coating is also the best option if you work in a facility where project demands have strict deadlines and time is not a luxury. However, spray painting is preferable if you have no scheduling limitations when working on a given project.

Reliability

When working with either spray paint or powder coats, you’re aiming for two objectives: durability and aesthetics. These two factors are crucial, especially with commercial products like automobiles or household appliances. 

You want to ensure that the color finish applied has high protective qualities to protect the metal surface from the elements as well as give the product an appealing look.

Naturally, metal is highly susceptible to corrosion and rust, caused mainly by exposure to water or moisture, and metal generally develops rust in spots. 

Excess rust can lead to the formation of holes within the metal surface which is why the coat of paint or powder should be solid enough to make the surface against corrosion resistance. 

The powder will generally offer this protection more so with heavy-duty parts guaranteeing superior, long-lasting protection. 

In addition, the polymer is highly resistant to the effects of chalking caused primarily by moisture, heat, and U.V. rays, so you don’t need to worry about discoloration on your metal surface. 

In comparison, wet paint undergoes a gradual breakdown of resins, resulting in fading if the object is exposed to the elements for long. The most durable powders that resist chalking are usually made from polyester.

Color Availability

Wet paints present a tremendous advantage with color matching. You can easily predict how the color theme will turn out even before you finish spray paint. 

This makes it possible to mix and match different paint colors accurately to achieve the desired color hue. It is one of the areas where powder coating trails, as it’s practically impossible to match color with this technique. 

You can precisely mix custom colors of liquid paint right on-site. For example, a mixture of blue and red will precisely give you a shade of purple, black and white will give you gray, etc. 

The same isn’t the case with custom powder coats. The colors undergo unique production runs largely determined by the plastics from which it is grounded. 

Powder coating has no solvent, so an attempt to blend yellow and green will only create a yellow and green speckle pattern, not blue.

This difficulty in color matching is why powder is typically produced in large batches of common colors. While it’s possible to order custom colors, it’s more expensive and time-consuming than wet paint.

Texture

Powder coating and spray painting work best with different types of textures. While you can achieve a smooth and glossy finish with both approaches, it’s much easier with liquid paint than with powder coats. 

Powder is more efficient with thick coats, so the texture you want to achieve depends on the project you’re working on. 

Compatibility with a Range of Substrates

Wet and spray paint does not require artificial heating processes to dry and cure. You don’t need to pass your spray-painted piece through the oven or electrostatic heating process.

You can easily spray paint fiberglass, plastics, and wood pieces and allow them to dry naturally, though you can make spray paint dry faster with other common methods, such as running a fan next to the object if time is not on your side.

With powder coating, binding, drying, and curing is best achieved with an electrically conductive source like an electrostatic gun. This makes it difficult to powder coat nonmetallic components since specialized processes for such projects are not readily available.

Equipment Requirements

You need electrostatic equipment and curing ovens to work with powder coats, yet spray painting only requires a spraying system and a good space to air dry.

The equipment requirements for powder coating may not be affordable for small-scale projects or businesses. 

To ascertain if investing in this equipment is worthwhile, consider the type of projects you’ll be working on and whether powder coating will be needed to meet those project specifications. 

If the high durability and functionality of these color coatings aren’t part of those specifications, consider investing in spray painting.

How Do You Apply Powder Coat Spray Paint?

As we have seen, powder coating entails applying plastic powder coating on a metal substrate. 

It’s then baked to a fluid form where it binds with the substrate. This color application technique has many advantages over spray painting. It’s environmentally friendly, provides thick layers and texture without drips and runs, and is easy to use. 

Although it comes with some drawbacks, powder coating isn’t a complex process, not for enterprising people who’re always looking for a new challenge. 

How you clean and prepare the surface and the tools you use determine whether you’ll create a professional or amateur outcome. 

If this is something you want to try in your next painting project, we could guide you through it. 

First, determine the type of material you want to paint with a powder coat, then choose the ideal powder for the finish. 

You’ll also need a thermoplastic or thermoset polymer powder that can bond to various base metals. 

Once the tools are ready, clean the surface you want to powder coat. Cleaning should be moderate or vigorous, depending on the condition of the substrate. 

Surfaces like cast iron or steel should be blasted to remove the excess mill and rust. If the surface has oil, grease, or old paint, use a chemical solvent and a little sanding to clean it up. 

For alloy metals like magnesium and aluminum, you can use a wire brush and chemical solvent to clean dirt.  

After surface preparation, it’s time to apply powder to the surface. Use a compressed air sprayer or a gun to electrostatically charge the powder material onto the metal object. 

After you’ve covered the entire surface, please resist the urge to brush or blow the powder coat until it cures to maintain consistency over the whole surface. 

The next step is to cure the metal object in a conventional oven at temperature ranges of 350° to 375° F (175° to 190° C). Note that using an oven is only recommended for smaller metal objects. 

If the project is larger, it’s preferable to use an infrared heat lamp or a similar flameless heat source is preferable. Your powder-coated project should be dry and fully cured within an hour, ready for use. 

Powder Coating vs. Wet Spray Painting: The Verdict

Powder coats and spray paints have several similarities. They each contain resin, pigments, and other ingredients. In addition, wet paint contains solvents and is the most widely available medium. 

Paint is affordable and has more color options that are easy to blend and match. It’s also much easier to achieve high gloss finishes with spray paint than with powder. 

In contrast, the powder offers better coverage, is easier to maintain, has greater durability, and does not require regular maintenance. But despite all these factors, the powder is slightly expensive, especially during the initial purchase. 

In general, wet paint and powder can succumb to the effects of wear, such as chalking, when exposed to the elements for a long time.  

Powder coating is becoming popular thanks to new technological advancements and reduced equipment costs, especially in industrial projects. 

While liquid paint is not going anywhere, powder coating is gaining considerable ground and will serve as the next best alternative.

FAQS: Powder Coating vs. Spray painting

Is powder coating better than spray painting?

Powder coating is much thicker and more durable, providing better protection against rust and other forms of damage in ways that spray paint cannot. While you need an oven to work with powder coating, spray paint dries naturally. Both paint options are suitable and applicable in different situations. 

Is it cheaper to paint or powder coat?

Initially, the cost of a powder coating project may be higher, especially when you factor in the cost of equipment. It does get cheaper in the long run. On the other hand, wet paint has been around much longer than spray paint, meaning the equipment and materials needed are readily available. Savings with spray painting may be obvious upfront, but it is costly in the long run.

Can you powder coat over old paint?

Yes, you can powder coat over an existing old paint though the results may not be satisfactory. It’s much better to strip or remove the existing paint on a surface before covering it with a new powder coat. It is advisable, though, to get professional painter to offer powder coating services if you are unsure how to go about this process.

How long will powder coating last?

The lifespan of a powder-coated material depends on a few factors, like the quality of preparation, the climate situation, the environment where the project will be used, and the type of powder coating used. A powder coat finish can last up to two decades or longer if these factors remain constant. However, if the project is exposed to U.V. lights or an outdoor environment, it can wear out faster. 

Summary

For a metal-fabricated component to last longer, it should be adequately protected. Surface finishing with power or wet paint is some of the best ways to achieve that. 

Powder coating and wet paint contain resin, color pigments, and other properties, though they also have significant differences. 

The most notable difference is the ingredients, whereas wet paint contains solvents that help transform the mixture into liquid form. 

Powder coating is generally made from polymer powder that contains no solvents, but it should be baked on the surface to create a smooth finish. 

Choosing between powder coating vs. spray painting should depend on the long-term goals you want to achieve with your project, though; overall, both options provide a smooth, beautiful finish on any surface.