Resharpen a Glazed Diamond Blade by Dressing It Against Another Blade

The Problem

A diamond blade that's cutting slower than it used to isn't necessarily dull or worn out. The diamond segments can get "glazed" — coated with a smooth layer of ground material, especially from cutting tile — which keeps fresh diamond grit from ever reaching what you're cutting. Buying a replacement blade skips right past a much cheaper fix.

The Technique

  1. Get a dressing stone — an abrasive block made for exactly this — or, in a pinch, another old abrasive blade.
  2. Run the glazed blade against the dressing stone (or the other blade) for about 10 seconds, the same way you'd run it through a normal cut.
  3. The abrasive action grinds away the glazed surface layer and exposes fresh diamond underneath.
  4. Test the blade on a scrap piece — it should bite and cut like new.
Pro tip: Do this at the first sign of slower cutting rather than waiting until the blade seems fully dull. Caught early, a glazed blade dresses back to full sharpness in seconds; let it go too long and you're better off just replacing it.