How Does Powder Coating Work?

Powder coating is a high-strength alternative to painting, and is used widely across the world. In this article, we’ll be exploring the concept of powder coating, how it works, how it stands up against painting, and more.

What is powder coating?

Powder coating is a finishing process that is used to add colour to objects (usually metal), and strengthen them beyond the capabilities of conventional paint. It’s a free-flowing, dry powder based on polymer resin, and combined with curatives, pigments, leveling agents, flow modifiers, and more.

Powder coating is used on a wide array of products, including bicycle parts, household appliances, cars, and motorcycles. It’s thought that powder coating takes around 15% of the North American finishing market¹.

How does powder coating work? | Powder coating process

Powder coating is usually applied electrostatic-ally using a process called electrostatic spray disposition (ESD). A powder feeder and spray gun are used to fire the powder onto the object using compressed air. As it leaves the gun, a positive electrostatic charge is applied, which is attracted to the metal object being painted, and sticks to it. Once the powder is applied, the object goes into a curing oven, which bakes the colour onto the surface by fusing the powder’s atoms with the metal, making it incredibly durable.
The other way to apply powder coating is through a process called fluidized bed powder coating. This works by heating the metal object, and dipping it in a fluidized bed powder coating, where the coating sticks to the object, before being baked on during the curing process.

For powder coating to be effective, the surface of the object must be cleaned and treated, to remove any dust, dirt, and debris. If the object isn’t thoroughly cleaned, the powder won’t be able to stick properly, affecting the quality of the final finish.

Recent developments have allowed powder coating to be applied to other materials like plastic and MDF. 

Powder coating vs painting

There’s pros and cons to both powder coating and painting:

• Powder coating creates a tougher finish than regular paint, but is a little more difficult and expensive to apply.
• Powder coating is better with textured finishes. But high-gloss finishes should be left to regular paint.
• Liquid paint is much better at colour matching than powder coating, with paint being easily mixable with a high degree of precision.
• Liquid paint is flammable, which makes it more dangerous to store.
• Powder coating has a higher upfront cost, but will last longer, so is cheaper in the long run.
• Paint is more widely available than powder coating.

Powder coating cost

As mentioned above, powder coating has a much higher initial cost than painting. You’ll need a special gun, hooks, air lines, and powder cups, which can set you back around $650. If you want a system with a fluidising drum, it leaps up to $5,000.

For the powder coating itself, you can expect to pay between $25 to $40 per kilo².

Can you powder coat aluminium?

Powder coating is commonly used to apply decorative and protective finishes to aluminium objects. It’s a highly versatile coating treatment option that allows a huge range of colours, number of different finishes, and a consistency that is guaranteed. It also has better colour uniformity between batches.

References

1. What is Powder Coating?, Powder Coating Institute
2. Powder Coating Australia, Coating.com.au
3. Anodising Vs powder coating: Which is better for aluminium surface treatments?, Architecture Design