![]() I hope this helps anyone wondering about why you may not be getting the proper mil thickness after coating the blasted metal. An electronic Mil Gauge is a bit more accurate but still reads less than the actual mil thickness due to peaks and valleys. If you are trying to get a wet mil thickness this even makes it lower because the wet mil gauge will only measure from the highest spots. 16 grit, you will get a lower average mil reading when checking the coating thickness. When You are reading mil thickness on paint, however, the peaks will have less mil thickness due to paint flowing to the low spots. If we used a 16 grit we could get up to a 10 mil average profile. As far as any blasting I have done in the past the SSPC SP 10Īs far as profile, we were always asked to get a certain average Mil reading usually about 2 mils was a 30 grit sand which is pretty fine. Thanks a lot for providing such informative things. Let us know if you seek something further, but clearly you can offer no certification and make no claim of compliance until you have obtained the standards. ![]() offers a free 24-page PDF with pictures of these surfaces at: The cleaned surface should have a uniform metallic colour but may show varying shades of grey when viewed at different angles. White Metal - Visible mill scale, rust and foreign particles are entirely removed. The cleaned surface will show varying shades of grey. Near White Metal - Mill scale, rust and foreign particles are removed to the extent that only traces remain in the form of spots or stripes. "Surface Preparation and Finishes for Metals" I want to know about SA-2.5 & SA-3 profile of sand blasting because I don't have the SSPC standards Same thing reflects for high thickness paint. Because it gives you high paint consumption. We cannot apply on 70 Micron Roughness surface. when we paint shop primer the requirement of DFT is 20 microns. Surface Roughness and Paint Thickness (DFT) is proportional to each other. After plating, the surface roughness should not change very much in most cases.įeather Hollow Eng. However, if the DFT is quite high, the underlying Ra is less noticeable. If a thin coating is placed upon a highly polished surface, the article will possibly look very different (shinier) than a case where the same coating is placed upon a mill finish or roughened article. ![]() Another example is a case where visual differences are desired. On the other hand, if a given coating is very thin, perhaps a very fine finish such as 8 or less will work fine. Therefore, if adhesion is critical and the coating is fairly thick, 63 Ra or higher may be appropriate. ![]() One thing to keep in mind is that a thick coating on a very smooth surface does not stick as well, in many cases, compared to the same coating on a lightly roughened surface due to a smaller surface/contact area. ![]()
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