Is surface preparation necessary? If yes, what standard should be followed?

Yes, a good surface preparation is essential to get optimal resin bonding and guarantee the sustainability of the repair. The prepared surface should match with Sa 2½ or St3 standards and roughness reaches at least 60 microns (Rz). It can be done using grit blasting or Bristle Blasting (MONTI technology distributed in France by 3X).