Knowledge Base
What is viscosity in paints and coatings?
Viscosity is a fluid’s resistance to flow. In paints and coatings it governs how a product brushes, sprays, rolls, levels, and resists sagging, and it is one of the most routinely checked quality parameters on the line and in the lab. A coating that is too thick drags and clogs; one that is too thin runs and sags. Controlling viscosity keeps film build, appearance, and coverage consistent from batch to batch.
Because coatings behave differently under different conditions, there is no single viscosity test. The right method depends on the product and how it is applied:
- Flow cups measure the time a sample takes to drain through an orifice, giving a fast kinematic viscosity check to ISO 2431 or DIN 53211.
- Krebs viscometers report mid-range paint viscosity in Krebs units.
- Rotational cone-and-plate viscometers measure dynamic viscosity at high shear, close to real application, to ISO 2884.
- Multi-spindle (Brookfield method) viscometers cover a broad range of fluids.
Industrial Physics provides this range through its TQC Sheen brand for quality, R&D, and operations experts in the paints and coatings industry. From the Digital Krebs Viscometer to the Cone and Plate Viscometer, each instrument is built for accurate, repeatable results to recognized standards, helping protect the integrity of the coating and the brand that relies on it.
Was this useful?
Related Products
-
Online Range
TQC Sheen Krebs Viscometer
The TQC Sheen Krebs Viscometer DV2300 is a digital rotational viscometer that measures paint and coating viscosity using the KREBS method - a paddle rotating at a constant 200 rpm in a fixed volume of sample. It converts torque into three simultaneous outputs: Krebs units (KU), centipoise (cP) and grams (g), with automatic unit conversion shown on the LCD display. Used by paints and coatings QC laboratories, paint manufacturers, automotive OEM coating suppliers, printing ink producers, adhesive manufacturers and cosmetics QC labs, the DV2300 supports ASTM D562 Krebs-unit specifications alongside direct viscosity readings for a wide range of Newtonian and near-Newtonian fluids.
-
Online Range
TQC Sheen Viscosity Cups (Dip/Immersion), according to ISO 2431
The TQC Sheen Viscosity Cup ISO 2431 (Dip/Immersion) is a flow-time viscosity cup compliant with ISO 2431 - in dip/immersion form with a handle for point-of-use paint and coating viscosity checks directly from the container. Available in multiple orifice sizes covering the paint viscosity working range.
-
Online Range
TQC Sheen Multi Spindle Viscometer
Our modern digital viscometer conforms to the Brookfield method and it’s ideal for a wide range of viscosity testing applications.
FAQs
-
It depends on the product and how it is applied. Use a flow cup for a quick check of thin products, a Krebs viscometer for mid-range decorative paints in KU, and a cone-and-plate viscometer for dynamic, high-shear measurement of non-Newtonian coatings.
-
A flow cup measures how long a sample takes to drain through an orifice, giving a fast, relative kinematic reading. A rotational viscometer measures the torque needed to turn a spindle, cone, or paddle in the sample, giving dynamic viscosity and the ability to measure at a controlled shear rate, which matters for non-Newtonian coatings.
-
The TQC Sheen Cone and Plate Viscometer controls shear to 10,000 s-1 for BS and ISO methods, or 12,000 s-1 for ASTM. These rates represent application by roller or brush, so the measured viscosity reflects how the coating behaves in real use rather than at rest.
-
Viscosity is strongly temperature dependent, so a small change in sample temperature can shift the result. Reliable testing means measuring at a defined, stable temperature, and comparing results only when they were taken under the same conditions.
-
Krebs units (KU) are a paint viscosity scale from the Krebs paddle method, in which a paddle turns in the sample at 200 rpm and the torque is converted to KU. The Digital Krebs Viscometer reports KU, centipoise, or grams, and is widely used for architectural and decorative paints.
Related Articles
-
Viscosity describes how easily a liquid flows. A high-viscosity coating is thick and slow moving; a low-viscosity one is thin and runny. For paints and coatings this single property influences almost every stage of use, from how a product is pumped and dosed in production, to how it atomizes at a spray gun, to how…
-
Key terms Term Definition Viscosity A fluid's resistance to flow. Dynamic viscosity Resistance to flow under an applied shear, measured in pascal seconds (Pa.s), poise (P), or centipoise (cP). Kinematic viscosity Dynamic viscosity divided by density, measured in centistokes (cSt); what a flow cup effectively reports. Shear rate The rate at which a fluid is…
