Viscosity

Viscosity determines whether a material can be applied, how it flows out and whether it stays put on a vertical surface. It is therefore the property tested most often and most quickly — at goods inwards, before the batch is made up and continuously in production. Because it depends strongly on temperature, a reading without a stated temperature is worthless.

The flow cup measures an efflux time and is sufficient wherever the same material is repeatedly checked against itself. As soon as a material is shear-thinning — that is, changes its viscosity under shear, as almost every modern coating does — a single efflux time says too little. Then a rotational viscometer is needed, measuring at a defined shear rate and, across several shear rates, revealing the flow behaviour.

What matters when choosing

• Newtonian or shear-thinning material — this decides cup versus rotation
• Viscosity range and the matching cup orifice or spindle
• Temperature control: without a defined temperature the value is not comparable
• Laboratory or line — operation with gloves and cleaning effort
• Customer requirements on which method counts as evidence
• Documentation and transfer of the readings into QC

Instruments in this category

Trade names from our range. Click a name to ask Corvus — he knows the technical data and helps you narrow things down.

Data sheets, operating manuals and quotations are available on request. We quote prices individually, because configuration, accessories and the scope of calibration decide the figure.

After the purchase

An instrument is only worth something once its readings hold up. Calibration, adjustment, repair and operator training are handled from Aesch — the same contact, the same language.