A Zahn cup is a portable, U-shaped viscosity measurement device widely used in the paint, coatings, and adhesives industries. It determines fluid thickness by measuring the time (in “Zahn seconds”) it takes for a liquid to empty through a calibrated orifice at the bottom.
Types of Zahn Cups
There are five standard Zahn cup sizes, labeled No. 1 through No. 5, defined by the size of their orifice:
- No. 1: Smallest orifice; for very thin liquids like light lacquers.
- No. 2: For light oils, mixed paints, and varnishes.
- No. 3 & 4: For thicker coatings, adhesives, and heavier mixtures.
- No. 5: Largest orifice; for highly viscous fluids.
