Powder coating is not a monolith. “Powder” can mean a lot of different things at the chemical level, which is why we can’t (or shouldn’t) spray leftover powders indiscriminately on incoming parts. Different applications require different powder chemistries.
Of all the powder chemistries available on the market (and there are a lot), I want to focus on the three main categories: epoxy, polyester, and hybrid powders.
Epoxy has good chemical resistance, but does not hold up well against UV light. When exposed to the sun, epoxy coatings will chalk and fade in as little as two weeks. This makes epoxy powder coating ideal for indoor applications. At Kaser, we often use epoxy as a primer – it creates a hard barrier between the part and any chemicals (i.e., cleaning products) it might encounter, creating a base over which we spray a UV-resistant polyester top coat.
Polyester powder is the poster child of the powder coating industry. When you picture a glossy, colorful top coat, it’s likely polyester. Polyester powder coating is far more resistant to UV light than epoxy powder. It also comes in either “regular” or “super durable” formulations, which hold up well against direct sunlight for one year or five years, respectively. This makes super durable polyester powder ideal for outdoor application.
Polyester and epoxy powders can be mixed to create a hybrid formula for indoor application. Used for shelving, light fixtures, and office furniture, this hybrid holds up well against cleaners, but should not be exposed to too much UV light.
When customers bring me a part, I always ask questions about its purpose: will it go indoors or outdoors? Will it be exposed to cleaners and other chemicals? What is the customer looking for in terms of gloss and color retention? All of this will directly impact the powder chemistry I recommend for the project. Learn more here.