ISO 2409
Paints and Varnishes — Cross-Cut Test
Specifies a cross-cut procedure and 0-to-5 classification for resistance of paint coatings to separation from a substrate or underlying coat.
What ISO 2409 specifies
ISO 2409 assesses a coating by cutting a right-angle lattice through the film, brushing and optionally taping the area as specified, then comparing detachment with reference classifications. Classification 0 is the best result, with smooth cut edges and no lattice-square detachment; classification 5 is the worst. Cutter spacing is selected according to film thickness and substrate. The method is quick and useful for process control, but it does not measure tensile bond strength and is unsuitable for some very thick, textured, or highly resilient coatings. Requirements should state the maximum permitted classification and relevant test conditions.
ISO 2409 types and classes
Every designation the document defines, with the thickness it requires and the tests it imposes.
| Designation | Meaning | Requirement / test |
|---|---|---|
Classification 0 | Cut edges completely smooth; no lattice squares detached | Visual comparison after cross-cut procedure |
Classification 1 | Small flakes detached at intersections; affected area not significantly greater than 5% | Visual comparison after cross-cut procedure |
Classification 2 | Flaking along edges or intersections affecting more than 5% but not significantly more than 15% | Visual comparison after cross-cut procedure |
Classification 3 | Flaking in ribbons or parts of squares affecting more than 15% but not significantly more than 35% | Visual comparison after cross-cut procedure |
Classification 4 | Large ribbons or squares detached, affecting more than 35% but not significantly more than 65% | Visual comparison after cross-cut procedure |
Classification 5 | Flaking greater than classification 4 | Visual comparison after cross-cut procedure |
Tests and the drawing call-out
Tests the document imposes
- Single-blade or multi-blade cross-cut
- Brushing
- Tape pull where specified
- Visual classification 0–5
How to cite it
Drawing call-out
CROSS-CUT ADHESION PER ISO 2409, MAXIMUM CLASSIFICATION <0–5>Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
Finishes specified to ISO 2409
Ink StampingMarking & decorationInk stamping transfers a fixed image from a rubber, polymer, or metal stamp onto a part.CorrosionHardnessCost$
Pad PrintingMarking & decorationPad printing transfers ink from an etched plate to a part with a flexible silicone pad.CorrosionHardnessCost$
Screen PrintingMarking & decorationScreen printing pushes ink through a patterned mesh onto a part.CorrosionHardnessCost$ISO 2409 — frequently asked
Is ISO 2409 class 0 good or bad?
Class 0 is the best result; no lattice squares detach. Class 5 is the worst classification.
Is ISO 2409 the same as ASTM D3359?
Both are cut-and-tape adhesion assessments, but their procedures and rating scales are not interchangeable.
Does ISO 2409 measure adhesion strength?
No. It gives a visual classification after cutting and separation; it does not report tensile bond strength.
ISO 2409 is copyrighted by International Organization for Standardization. This page explains the document so a drawing can be read; it does not reproduce the standard. Purchase the current edition from the publisher. Official source ↗