For industrial applications, powder coating offers superior durability and efficiency.

However, wet painting makes it easier to switch between different colours, achieve thin finishes or coat heat-sensitive materials – and it can be done in-house without requiring heavy investment in equipment.

Below, we compare powder coating versus wet painting to help you decide which one is best for your application.

A basic comparison of the finishing technologies

To understand the benefits of each painting method, you need to know how they work and what’s involved in the application.

How powder coating works

Powder coating involves spraying a dry powder onto a metal surface with an electrostatic gun. The metal item is grounded and the powder is given a negative charge by the spray gun. The powder is attracted to the metal and rapidly sticks to it in an even coating.

Spraying must be done in a spray booth with ample space and suitable hanging racks.

Once the metal item is sprayed to the desired thickness, it goes into a curing oven. The heat creates a thermal bond between the powder particles.

The powder is made from resins, curing agents, pigments and other additives that are ground into a fine powder. A primer is often applied before powder coating.

Powder coating, also known as electrostatic spray deposition (ESD), results in an exceptionally hard, smooth and durable finish.

What’s involved in industrial spray-painting

Wet painting involves liquid paint that is sprayed onto a surface with a spray gun. There are different types of spray guns depending on the application and budget. These include air-atomising, electrostatic and airless spray guns.

Because it is liquid, applying wet paint requires more skill than powder coating or the finish could be uneven and the paint form runs and drips.

Spraying with wet paint must be done in a spray booth with adequate ventilation and PPE.

Some paints require curing in an oven with heat; others air dry, which means you need space for drying racks. Like powder coating, a primer is usually applied first.

With skilled application, wet paint can result in an exceptionally smooth finish. The durability depends on the type of paint, topcoat and material of the item being sprayed.

Performance comparison: powder coating vs. wet paint

Each type of spraying has pros and cons. The item being sprayed plays a role in which is most suitable, as does the performance of each method.

Strength and durability

Powder coating offers a tougher finish compared to wet paint. It is highly resistant to chipping, cracking and environmental wear due to the thermal curing it undergoes and because it can be applied in very thick layers.

Powder coating offers better colour retention; liquid paint usually fades with prolonged UV exposure. That said, powder coating colour will eventually break down with enough exposure to moisture, sunlight and heat. This is known as chalking.

Polyester-based powder coatings are exceptionally chalk resistant. They are often used as a topcoat.

Maintenance is less necessary with powder-coated items but harder to achieve. Spray-painted items need more frequent maintenance but it’s much easier to do.

Range of materials

Powder coating works best on metals. Its application on other materials is limited. To powder coat plastic, for example, you need special low-temperature powders or UV-cured powders.

Wet paint can be applied to many more materials. Anything from metal and plastic to wood and glass can be spray-painted with the right choice of paint and a suitable spray system.

Colour matching and textural variation

Liquid paint is the clear winner when it comes to colour matching. Liquid paint can be mixed to just about any colour with great precision.

By comparison, powder coating is limited to the colours that can be created by adding pigments to the powder mix and, with no solvent, colours can’t be mixed to form new colours.

With finishes, both have their strengths and weakness. It’s easier to achieve a high gloss with liquid paint; powder coats are more textured when thin and smoother when thick.

It’s easier to add a non-slip texture to a powder-coated finish, making it ideal for metal stairs and walkways.

Liquid paints can achieve texture through additives, but these aren’t always suitable for spray applications or industrial environments.

Health and environmental safety

Liquid paint contains volatile organic compounds (VOCs), which are harmful when inhaled and are considered a major source of industrial pollution.

Wet-paint applications require more safety protocols, such as higher ventilation and PPE. The powders used for powder coating are easier and safer to store.

There may be more waste with wet painting due to over-spray. Paint usually contains solvents that powder coating doesn’t, so regulations for disposal tend to be stricter.

Cost

Over the long term, powder coating is more cost-effective than wet painting, but the upfront costs of equipment are greater. As a result, many businesses choose to outsource it.

If the volume of work is sufficient and there’s potential to offer powder-coating services to other business in your area, investing in equipment is worth it in the long term.

There’s also less waste with powder coating because the over-spray powder can be collected and reused.

By comparison, the cost of setting up an industrial spray-painting system is relatively affordable and easy to implement. An entry-level spray system, fluid transfer system and suitable spray booth can get you started. There is also scope to grow using automation if there is sufficient demand.

However, the waste and extra safety protocols needed for wet paint add to the overall cost.

Checklist: which is better for your application?

This handy checklist gives an overview of the pros and cons of each method to help you decide which one suits your needs.

Which one is the best pick?
	Powder coating	Wet painting
Durability: highest resistance to chips and cracks	X
Cost-effectiveness: long-term, overall cost-effectiveness	X
Ease of set-up: easiest to set up and get started		X
Ease of application: least amount of skill required to apply	X
Applications: range of materials you can coat or spray		X
Applications: suitable for industrial applications?	X	X
Applications: suitable for home applications?		X
Colour stability: highest resistance to colour fading	X
Colour matching: highest range of colours available		X
Colour switching: ease of changing paint colours		X
Colour combining: combining more than one colour on a painted item		X
Texture and finish: range and ease of texture finishes	X
Health and safety: lowest health and safety impact	X
Environmental impact: lowest environmental impact for application and disposal	X
Maintenance: best for ease of maintenance		X
Maintenance: lowest frequency of maintenance	X

If you’re still unsure about which spray system you need, contact us for expert advice. We stock a range of spray guns, powder-coating equipment, sprays booths and more to help you set up an industrial spray system that covers your needs.