What Factors Impact the Cost of Powder Coating?

Powder coating is a highly effective way of treating metal surfaces to protect them and give them a decorative finish. 

Obviously, this comes at a price, but what factors impact the cost of powder coating?

What Determines the Cost of Powder Coating?

What you pay for powder coating will include the cost of materials and the expense involved in preparing, spraying, curing and drying – powder coating is a process as well as a product.

Another critical factor is what it is you’re spraying. If you’re powder coating small parts, for example, you will pay a price per job. However, for larger parts, you pay by surface area and the cost per kg of the powder coating you choose.

Also, there are different types of powder coating, and these vary in price.

What is the Powder Coating Process?

The powder coating process can involve several stages.

First, there is pre-treatment and cleaning. Not all parts will be immediately ready for having a powder coat applied to them. In fact, many of them will be oily, greasy, or still have surface traces of paintwork.

Specialist pre-treatment methods include:

• Degreasing
• Phosphating
• Chromating
• Shot blasting

These various processes will clean metal surfaces and parts to prepare them for powder coating applications.

Application involves spraying the coating onto the surface using an electrostatically charged spray gun.

Compressed air forces the dry powder coating through the nozzle, creating a fine, atomised spray that adheres to the metal surface.

This is due to the positive charge the gun gives the powder as it leaves the nozzle. This makes the powder adhere to the negatively charged surface, countering the effects of gravity and the powder’s natural aerodynamic behaviour.

A powder feeder controls the flow of powder through the spray gun.

This method reduces the amount of paint drift, ensuring the coating process is highly efficient, minimising waste.

Spraying takes place in a spray booth, normally equipped with a powder recovery system so that any over-sprayed powder can be collected and reused later.

After powder application, the coated part must be cured inside a convection oven.

Each component in powder coating must reach its optimum temperature, which then ensures that the coat hardens properly.

Under applied heat, the resins in the coating will melt and fuse together to form an even surface. The minimum curing temperature for most powders is 160° C, but there are specialist powders that require higher temperatures.

These powders will cure faster.

Following curing, the coating must cool, before the surface is ready for use.

What Types of Powder Coating are There?

There are two broad categories of powder coating, thermoplastic and thermoset. 

The key difference between thermoplastic and thermoset powder coatings is how they react to heat.

Most thermoset coatings set much harder following the curing process. This is because they undergo an irreversible change from their chemical reaction under heat.

In contrast, thermoplastic coatings can be reheated and remoulded.

Thermoset powder coatings include:

• Acrylic
• Epoxy
• Epoxy-polyester hybrids, and
• Silicon

Thermoset coatings are heat-resistant and some can withstand temperatures exceeding 500°C. They make good electrical insulators but may become brittle if you expose them to UV light for too long.

Thermoplastic powder coatings include:

• Polyester
• Nylon
• PVC, and
• Polyolefin

Thermoplastic coatings offer excellent protection from wear and tear and are resistant to chemicals. However, they are less heat-resistant than thermoset powder coatings.

Thermoset powders have the most widespread use, with thermoplastic being comparatively more expensive due to its specialist applications.

Therefore, the type of powder coating you choose will be another factor in how much this will cost.

What are the Main Components of Powder Coating?

The main components of powder coating are resins, such as polyester or epoxy, plus paint pigments, which provide a range of colours. 

There are other ingredients such as additives. These act in various ways to alter and improve the basic components. Some additives will provide a matt effect, while others will help harden the finish of the coating.

For example, benzoin reduces the melt viscosity and surface tension of thermoset powder coatings.

Other additives prevent caking in cured coatings, and various extenders and fillers will give powder coatings extra durability.

What is the Cost of Powder Coating?

We’ve looked at some of the factors that influence the cost of powder coating, including the coating process and the type of materials you choose.

For regular, smaller parts such as wheel rims or bicycle frames, many providers will charge per item.

For larger surface areas and parts, powder coating tends to be priced by the amount you use per square metre. You can usually expect it to be more cost-effective the greater the volume of powder coating you require.

Flat rates and bulk rates will vary depending on your chosen provider.

Another factor that can affect price is colour. You can colour-match most powder coatings, but, depending on the pigment, colour costs will vary too.

How to Choose the Right Powder Coating

There is a broad range of powder coatings available, so it’s important to choose the appropriate type of coating for your purpose. The type you choose will have an impact on the cost of your powder coating project:

• Polyester powder coatings are very much multi-purpose, for use on outdoor surfaces, including building exteriors.
• Nylon powder coatings are good for moving parts like gears and conveyor belts because of the low friction coefficient of nylon – these coatings are also hard-wearing and impact-resistant
• PVC powder coatings are good for providing insulation
• Polyolefin powder coatings offer good resistance to abrasion and chemicals, providing a smooth finish while adhering well to metal substrates
• Epoxy powder coatings are tough and good electrical insulators but become brittle if exposed to UV light
• Epoxy-Polyester hybrids have a more softened epoxy coating, making them less brittle and giving them improved weathering properties
• Acrylic powder coatings offer good UV light resistance with a high-gloss finish, making them ideal for primarily decorative applications
• Silicon-based powder coatings are hard-wearing and they're the most heat-resistant of powder coatings, withstanding temperatures exceeding 500°C.

What Can You Use Powder Coatings For?

Main applications for powder coating provide external finishes to metal products and parts.

Thermoplastic and thermoset powder coatings are used to protect aluminium parts and surfaces. You’ll find powder coatings on external architectural building features and on street furniture such as road signs.

Powder coating protects agricultural and industrial machinery and various car parts, including door handles and wheel trims.

Familiar and popular items such as garden and office furniture and golf carts are powder coated for both cosmetic and protective reasons.

Zinc powder coating is an epoxy-based anti-corrosion primer for steel surfaces, over which you can then apply your choice of paint finish.

Is Powder Coating More Cost-Effective than Paint?

As a dry application, powder coating is an alternative to liquid paint. It is generally much more efficient to apply than liquid paint, and it minimises waste.

These factors contribute to its cost-effectiveness. 

The powder coating process is rapid, and speeds up product-to-market rates. Typically, you require only a single powder coat to achieve the equivalent finish that would require several coats of liquid paint.

Powder coating is also more versatile than liquid paint because it comes in so many different types for both general and specialist applications.

Many liquid paints contain resins that will break down under certain environmental conditions, reducing their effective lifespan. With greater durability, powder coatings offer improved long-term performance.

You may find that powder coatings come with a higher price point up front, but they will more than repay your investment in terms of durability and longevity.

For more information about powder coatings and their applications, please contact us.