Overview
EN ISO 9117-5:2012 - Paints and varnishes: Drying tests - Part 5: Modified Bandow‑Wolff test (ISO 9117-5:2012) specifies a practical laboratory method to determine whether a coating (including multi‑coat systems) has reached defined drying stages and to assess drying speed. The method combines a ballotini (glass bead) surface test for early drying with a load/drop test using paper, rubber discs and specified weights to classify drying stages 1–7. The standard notes limitations for plastic (elasto‑plastic) coatings, where later drying stages (4–7) can only be assessed to a limited extent.
Key topics and requirements
- Scope: Determines drying stage reached and drying speed for coatings applied to standard test panels.
- Test conditions: Performed in triplicate at (23 ± 2) °C and ambient relative humidity unless otherwise agreed.
- Sampling & preparation: Samples and panel preparation follow ISO 15528 and ISO 1513/1514; wet‑film thickness measured per ISO 2808.
- Apparatus:
- Ballotini (small transparent glass spheres) for stage 1 test.
- Soft‑haired brush, paper discs (≈26 mm), rubber discs (≈22 mm × 5 mm, 50 ± 5 IRHD), and weights (20 g, 200 g, 2 kg, 20 kg).
- Stopwatch.
- Procedure:
- Stage 1: Pour ~0.5 g ballotini from 50–150 mm; after 10 s tilt and brush - all beads must brush off without surface damage.
- Stages 2–7: Place paper + rubber disc, apply specified weight for 60 s, remove and drop panel ~30 mm onto wooden support; whether paper drops and whether the surface shows visible changes defines the stage. Weights scale from 20 g up to 20 kg.
- Test report: Must identify the product, reference ISO 9117-5, detail panel prep, application method and drying, wet‑film thickness and measurement method, results of three determinations (stages and times), deviations, anomalies and date.
Applications and users
- Who uses it: Coatings manufacturers, QC and R&D laboratories, independent test houses, specifiers and purchasers of industrial, decorative or protective coatings.
- Practical value:
- Routine quality control of drying performance.
- Comparative evaluation of formulations or multi‑coat systems.
- Verifying drying behavior under agreed conditioning before shipment or assembly.
- Limitations: Best used alongside other drying tests (e.g., ISO 9117‑1, ISO 9117‑3) because film‑formation mechanisms and elasto‑plastic behavior can complicate interpretation of higher drying stages.
Related standards
Keywords: EN ISO 9117-5:2012, Modified Bandow‑Wolff test, drying tests, paints and varnishes, drying stages, drying speed, ballotini, test panels, coating quality control.