Overview
ISO 6272-2:2011 - Paints and varnishes: Rapid-deformation (impact resistance) tests - Part 2 describes a standardized falling-weight test with a small-area spherical indenter. The method evaluates the resistance of a dry paint or varnish film to cracking or peeling when subjected to rapid deformation produced by a falling mass acting through a small spherical indenter. Note: the apparatus produces rapid deformation rather than a true impact, and the test has limited reproducibility when numerical values are reported.
Key topics and technical requirements
- Test principle: A calibrated mass is dropped down a vertical guide tube onto a hardened steel, small-area spherical indenter that deforms the coated panel. The test identifies the height at which cracking or detachment first appears.
- Apparatus essentials: tube-guide (0.6–1.2 m), mass cylinder (1 000 ±10 g or 2 000 ±20 g), indenter (150 ±15 g with hemispherical head 12.7 mm or 15.9 mm), panel support with centered hole (16.3 ±0.1 mm) and ×10 magnifier.
- Specimen preparation: Coatings applied to thin metal panels prepared per ISO 1514 and conditioned/dried per manufacturer instructions; dry-film thickness measured per ISO 2808 (accept ±10% of specified thickness).
- Conditioning and environment: Panels conditioned at (23 ±2) °C and (50 ±5) % RH for at least 16 h (or other agreed ISO 3270 conditions). Begin testing promptly and complete within 30 minutes after removing specimens from conditioning.
- Inspection and detection: Visual examination with magnification and/or copper sulfate (acidic CuSO4) staining to reveal cracks or substrate exposure.
- Data and limitations: Because of poor interlaboratory reproducibility, numerical heights (mm) are recommended for comparisons within a single laboratory; ranking is preferred for interlaboratory comparisons.
- Reporting: Test reports must include product ID, reference to ISO 6272-2:2011, panel and surface prep, application and drying details, dry film thickness and measurement method, test temperature and RH, indenter diameter, whether coated or uncoated face was struck, test result (limit height), deviations and anomalies, and date.
Applications and users
- Coating manufacturers and formulation chemists evaluating film toughness and deformation resistance
- Quality control and R&D laboratories assessing product consistency or process changes
- Specification writers and test houses verifying performance for protective, industrial and automotive coatings
- Comparative ranking of coatings for product selection when laboratory reproducibility is ensured
Related standards
Keywords: ISO 6272-2:2011, falling-weight test, paint impact resistance, small-area indenter, rapid-deformation tests, coating testing, paint and varnish standards.