Important Break-In Procedure
Diamond resin discs are shiny when new. This shine must disappear in order for the discs to perform their best, especially with the finer grits (400 and up). To do this, run any new disc on a rough surface - such as granite, sandstone or concrete - always making sure there is enough coolant (water). This will force the outer bond to be eroded, leaving the diamonds properly exposed for polishing. They will gradually perform even better as normal wear sets in.