Pinholes and craters are two common coating defects that make the paint look bad, compromise corrosion protection, and require a complete redo of the project. By understanding the root cause of these issues, painters can avoid them in the first place and promote the best possible performance of their Cortec® Coatings system.
Where Do Pinholes, Craters, and Similar Defects Come From?
Pinholes are tiny holes in the coating. Craters are larger holes. Both create weak points where corrosion can begin. These defects are almost always caused by contamination. Grease, dirt, oil, or dust on the metal changes the coating’s surface tension, causing the rest of the paint to pull away from that spot and create a gap in the coating. Pinholes can also be caused by air bubbles that do not break until after the coating has dried. One culprit is vigorous mixing that creates too much foam.
How to Prevent Pinholes and Craters
The number one way to prevent pinholes, craters, and similar defects is to clean and dry the surface before coating it. Rinsing the metal with a VpCI®-41x Series cleaner is especially beneficial for surfaces that have been sandblasted down to white metal and are at risk for flash rust as they wait to be painted. Foam control is also important. If painters are mixing the paint too rapidly, they simply need to slow down to create less foam. Other times, the problem takes place in production, and the coating manufacturer may need to modify their formula.
Do It Right the First Time
No one wants to redo a paint job and have their previous efforts wasted. That is why it is critical to guard against contamination and excess foam from the outset. By taking the precautions mentioned above, painters can get their Cortec® Coatings application off to a good start for better coatings success in the long run. Contact Cortec® Coatings for further assistance to prevent and diagnose these and other coatings problems:
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