![]() ![]() Make sure dirt and debris have been completely removed. It may need blasting, washing, chemical pretreatment, or all of these processes. How can pinholes be eliminated? Diligent Metal Preparation During any phase, oil can leave a surface tension-inhibiting residue that prevents the hole from closing, causing an issue similar to “fisheye” in liquid painting. Air or moisture coming through during the powder’s liquid state doesn’t usually cause a problem because the coating material flows back together and reforms before it reaches a gel state. It can be caused by air, water, or oil coming through the powder during the gel state. A pinhole is caused by a disruption in the gel state of the powder that prevents the powder from achieving a uniform finish. During curing, the applied powder melts into a liquid, then spreads into a film, and begins to gel before it is cooled and hardens. I'll leave it at that and see if that gets you thinking anything different.A pinhole is a tiny, usually circular, void in a powder coated finish that is visible on the surface of a coated part. Now, the primer coat could also be producing the opposite effect in which the primer surface absorbed the 1st coat which can be witnessed by the fact you say you didn't experience "sliding" at that time. This is just one of those areas I would need to physically witness to diagnose properly. This can be explained by the fact you didn't experience it applying the 1st coat over the primer coat. It can also be related to surface tension, meaning, the first coat produced a poor surface. Typically orange peel is going to be related more often to 1) poor atomization 2) too close 3) too slow 4) lousy paint. Not to say its not possible, just seems unlikely thinking about how I spray for comparison. I just can't image you would have time to notice such a (sliding) effect occur. The thought of you being able to witness the paint doing anything is incomprehensible to me. You said a few things in your post that lead me to believe you were too close to the surface for your second coat or you were moving too slow. The main difference between fisheye and cratering or (dimples) is that fisheye is caused by something contaminating the surface whereas cratering or dimples are often caused when no surface contamination is present. Possible issue 2 - Warning sign of imbalanced system Surfactants play a role in wetting, coalescent and pigment dispersant agents contributing to the application of coatings, film formation and the development of color. Note: defoamers can degrade with age, some have a 12-18 month life span. Semi-gloss or gloss paints have a higher level of surfactants compared to flat paints. Think of surfactants as soap (lubricant) to allow paint to flow and level. Paints contain surfactants and defoamers. Cratering or (dimples seen in the photo) can be caused by heavy builds possibly applied too fast, or an imbalanced or (unstable) paint formulation. ![]() For example, fisheyes on a surface can be caused by oily residue, surface contamination, or primer/paint incompatibility, but not always the cause. Often "fisheye" and "cratering" or (dimples) are mistaken or vice versa because their appearance is similar. Things are not always what they appear to be. What is the difference between fisheye and cratering? ![]()
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