Professional Detailing2 min read

Scratch-Test Tip Geometry: A Load Number Is Not Enough

A scratch-test result should identify the tool geometry as well as the applied load. Different tips can create different contact conditions, so a load-only comparison is incomplete.

Updated · NANOLAB Knowledge

The key distinction

Taber describes multiple scratch tools with different shapes and tip dimensions. The laboratory should select the appropriate configuration and retain it in the report rather than reducing the test to one force value.

Practical checks

  1. Record the tool identity and geometry.
  2. Preserve the load, movement and evaluation criterion.
  3. Ask the laboratory whether reports use comparable configurations.

Example

Illustrative example: two coatings are tested with different tip shapes at the same nominal load. The shared load does not establish that the specimens experienced equivalent scratch conditions.

Scope and limits

Do not present a scratch-test load as a universal hardness rating. This guide does not specify a NANOLAB acceptance limit or authorize destructive testing on customer property.

Related guidance

Technical references: Taber: scratch-testing geometry. These sources describe their stated methods or products; they do not certify NANOLAB products or establish compatibility with an unlisted surface.

Ask NANOLAB about the exact product and intended use. Use the current product documentation for formulation-specific instructions.

Professional Detailing2 min read

Solvent-Rub Resistance Is Not a Universal Full-Cure Test

A solvent-rub result describes resistance under a specified test. It does not automatically prove that a coating has reached every property required for service or that the same result applies to another solvent.