Summary of What's the Difference Between Paint and Coatings?

00:00:00 - 00:10:00

This video explains the difference between paint and coatings, and how coatings provide greater corrosion protection than paint. Coatings are applied over a prepared surface and must be inspected for proper coverage. If any part of the coating is not covering the surface, an alarm will sound. Once the system passes the quality control check, the structure can be put into service.

• 00:00:00 This video explains the difference between paint and coatings, and how coatings provide greater corrosion protection than paint. The difference between the two is that coatings are used for protection, while paint is for decoration. Abrasive blasting is used to clean the surface before applying a coating, and is essential for good adhesion of the coating.
• 00:05:00 The major difference between paint and coatings is the size of the peaks and valleys on the surface. Paint typically has smaller peaks and valleys than coatings. One way to measure this is to use a stylus with a sharp point to draw a line across the surface. Another method is to use a depth micrometer to measure the profile. Lastly, you can use replica tape to measure the surface profile. When coating steel, the surface must be prepared properly in order for the coating to be effective. This includes roughening the surface up with a flap disc grinder or sand blasting, and then applying an epoxy primer. The next coat, called the midcoat, is often a polyurethane, and the topcoat is usually a polyurethane or epoxy. Coatings must be inspected for coverage after application and dried.
• 00:10:00 The difference between paint and coatings can be difficult to see by eye, and defects (called holidays) can be hard to spot. Holiday detecting devices are used by coating inspectors to make sure there are no uncovered areas of steel. Most of them work just like the game of Operation, but with higher voltage and fancier probes. If any part of the probe touches bare metal, an alarm will sound, notifying the inspector of even the tiniest pinhole or air bubble in the coating. Once the system passes the quality control check, the structure can be put into service with the confidence that it will be protected from corrosion for the next several decades to come.