Waterstones

Water serves as a rinsing medium which prevents the stone‘s pores from clogging with abrasion debris and preserves its abrasion qualities. If the stone is not enough rinsed with water, the abrasion debris makes a paste that decreases the stone‘s abrasion qualities. Professional sharpeners make use of this principle to achieve a finer abrasion in order to compensate greater steps in grit.
The stones must be soaked in water for 10-15 minutes before use. Ceramic stones like Shapton stones hardly absorb water. With them, 1 minute of soaking is enough.

Waterstones differ with regard to their bond as well as to their abrasive.

The abrasive silicon carbide is highly effective and therefore used for coarse grits, whereas corundum is used for finer grits.

A soft bond allows the abrasive particles to be continually exposed during use and makes the stone highly effective. These stones are ideal for extremely hard low-alloy steels.

Coarse-grained alloy constituents in tool steels (e.g. chromium and vanadium) require a stone that wears slowly. The bond is harder, the stone stays flat for longer.