How Powder Coating Works

What is Powder?

Powder coatings are made of polymer resin systems, combined with additives to aid curing, add color, and enhance mechanical properties. The ingredients are combined, melted, cooled, and finally ground into a fine, uniform powder similar to icing sugar.

Unlike the liquid coating process, powder coating is a dry finishing process. During the powder coating process, dry powder is applied to a material's surface using electrostatic spray deposition, then heat cured and cooled.

There are three stages to this process: material preparation, coating application, and heat curing.

Electrostatic Spray Deposition (ESD)

For most metal parts being powder coated, the coating material is applied via electrostatic spray deposition. This application method employs a powder spray booth, powder hopper, and electrostatic spray gun.

• The spray booth is the work area for applying dry powder onto materials. It also serves as an air filter and overspray containment and recovery system, eliminating up to 95% of waste (versus liquid, for which there is no recovery).
• Fluidized powder is pulled from the hopper to the spray gun, which electrically charges the powder and applies it to the substrate.
• Substrate materials are electrically grounded during the process, causing the charged powder particles to cling to the surface.

Heat Curing

After the powder has been applied, coated materials are heated in an oven. Heat causes the powder to 'flow out'. In other words, the powder melts and gels together, forming ultra durable long-chain polymers with high cross-link density. These molecular chains are what give powder coatings their enhanced performance characteristics, as they are extremely durable and resistant to breaking down.