Industrial Sandblasting or abrasive blasting is a common method that is used to remove old paint, rust, mill scale and other debris in order to prepare a surface for inspection or coating. Most exterior coatings require the surface to be prepared as specified by Commercial Blast SSPC-SP6 (SSI-Sa2), or NACE #3. This specification states that when viewed without magnification, all of the rust, dirt, mill scale, prior coatings and foreign matter must be removed prior to recoating the surface. At least two-thirds of each square inch of surface area shall be free of all visible residues.
Interior coatings, however, typically require a cleaner surface as specified by SSPC-SP 10/NACE No. 2, Near-White Blast Cleaning. SSPC-SP10 is a more aggressive standard and states that when viewed without magnification, all of the rust, dirt, mill scale, prior coatings and foreign matter must be removed prior to recoating the surface. Random staining shall be limited to no more than 5 percent of each unit area of surface. This specification also demands cleaning out any rust at the bottom of pits in the metal.
Be aware that some sandblasting companies simply “brush” the surface down with the sandblaster to roughen the surface and then paint over the remaining debris or mill scale. It takes lots of abrasive material to properly prepare a surface for recoating. A few bags of sand won’t do the trick and an improper blast will shorten the lifespan of the coating.
At Agri Painting Inc. we meet or exceed all of the surface preparation requirements as specified by the coating manufacturer to ensure the maximum lifetime of your coating.
