The durability of a coating depends on the cleanness of the surface on which the coating was made. The required degree of cleanness is determined according to the load of the coated surface.
To determine the degree of cleanness the Swedish standard SIS 055900 is used in Europe. This standard has been included in DIN 55928 in Germany. Here the degree of cleanness is determined on the basis of comparative lists.
When dealing with these lists it is of utmost difficulty to evaluate the surfaces. If the blasting process is performed with different abrasives or by using different grain diameters this will result in completely different degrees of brightness and structures.
It should be a matter of course not to blast the surface cleaner than asked for by the customer, because unnecessary extension of the blasting time reduces considerably efficiency.