When coating manufacturers formulate primers for brush or spray application, they optimise for completely different flow characteristics than what a vacuum coating system demands. A vacuum coater recirculates primer continuously at high flow rates through pumps, hoses, chambers, and filters. This creates three challenges that generic primers often fail:

First, high-speed recirculation introduces air — generic primers foam, creating bubbles in the finish. Second, continuous flow through narrow passages demands low-particle, anti-clog formulations. Third, the primer must level quickly after the profile exits the chamber, before the drying process begins.