Viscosity cup

Viscosity quantifies a liquid’s resistance to flow; in coatings it determines perceived “thickness,” atomisation and levelling. Measuring viscosity tells you how much thinner to add, how the coating will flow and how to set spray‑gun parameters. Viscosity cups measure efflux time: pour a specified volume into the cup and record how long the coating takes to drain through the orifice. Faster drain time indicates lower viscosity. Cup types differ by chamber volume, orifice diameter and wall profile (common examples: Ford and Zahn cups). Paint temperature also affects readings — measure with a paint thermometer or an infrared (laser) thermometer and correct viscosity accordingly.