--- type: "WebPage" title: "Measurement by incision: grid test or St. Andrew’s cross" description: "You wish to perform an incision or cross-test measurement on your coating Evaluate the adhesion of your coatings accurately Incision testing, whether the cross-cut test or the St. Andrew's cross test, is a simple and effective method for evaluating the..." resource: "https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization/measurement-incision-grid-test/" tags: ["EN", "pll_691aefa34f3c5", "Thomas GAUTIER"] timestamp: "2025-12-31T08:32:20Z" published: "2025-11-17T13:23:01Z" language: "en" author: "Laure Durieux" --- # Measurement by incision: grid test or St. Andrew’s cross ## You wish to perform an incision or cross-test measurement on your coating ### Evaluate the adhesion of your coatings accurately Incision testing, whether the cross-cut test or the St. Andrew’s cross test, is a simple and effective method for evaluating the [adhesion](https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization/laboratory-adhesion-analysis.md) of a coating to its substrate. Used at all stages of an industrial process, it allows verification of the durability of a [paint](https://filab.fr/en/our-services/our-analysis-services/polymer-materials-analysis-laboratory/laboratory-analysis-paint-varnish.md), varnish, [surface treatment](https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization/validation-of-surface-treatment-processes.md), or functional coating, whether during development, qualification, or quality control. ### Our incision measurement services At the Filab laboratory, we perform cross-cutting tests according to **ISO 2409** and **ASTM D3359**, as well as adhesion evaluations as specified by **ISO 16276-2**, which are particularly suited to corrosion protection systems. We also perform St. Andrew's cross-cutting when the geometry or nature of the coating requires it. Our services include: - creating a standardized cross-cut (1 to 6 cuts depending on the thickness), - creating a St. Andrew's cross incision when cross-cutting is not applicable, - applying standardized adhesive tape, - monitoring for any potential coating delamination, - classifying adhesion according to relevant standards, - providing detailed photographic documentation, - interpreting the results according to your industrial application, - and offering technical recommendations as part of expert support or R&D. ## The FILAB laboratory assists you with measurements by incision or cross-testing of your coatings ### Why perform a measurement by incision? The cross-cut test is the most common method for evaluating the adhesion of a [coating](https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization/laboratory-surface-coating-characterization.md) to its substrate. In addition to this approach, the St. Andrew's cross (an alternative method involving cutting an X into the coating) allows for a quick and qualitative assessment of the mechanical strength of a deposit, particularly on curved surfaces, surfaces that are difficult to access, or surfaces unsuitable for standard cross-cutting. These tests can identify: - a lack of adhesion, - insufficient surface preparation, - an application problem, - premature [ageing](https://filab.fr/en/our-services/our-analysis-services/polymer-materials-analysis-laboratory/laboratory-material-testing/filab-accelerated-ageing-test-laboratory/), or a material/coating incompatibility. ### Our additional analysis services Thanks to our comprehensive analytical facilities, we can supplement these tests with: a [surface analysis](https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization.md) ([AFM](https://filab.fr/en/our-technical-resources/atomic-force-microscopy-afm-laboratory.md), [XPS](https://filab.fr/en/our-technical-resources/laboratory-analysis-xps-esca.md), [SEM](https://filab.fr/en/our-technical-resources/laboratory-analysis-sem-scanning-electron-microscopy.md)) coating [thickness measurements](https://filab.fr/en/our-services/our-analysis-services/laboratory-surface-characterization/surface-coating-thickness-measurement.md) an observation by XPS, [Tof-SIMS](https://filab.fr/en/our-technical-resources/laboratory-analysis-tof-sims.md) of the [interface](https://filab.fr/en/our-services/our-analysis-services/polymer-materials-analysis-laboratory/laboratory-material-testing/analysis-material-interface-xps-tof-sims/) [compositional analysis](https://filab.fr/en/our-services/rd/problem-solving-related-research-and-development/accompaniment-in-solving-problems-of-chemical-composition-of-matter.md) to identify the origin of a [failure](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-failures.md) ## FAQ What is the purpose of a grid test? It allows you to assess the adhesion of a coating (paint, varnish, functional deposit, etc.) to its substrate. It is a quick and standardized test to detect peeling, application defects, or insufficient surface preparation. What is the difference between a grid and a St. Andrew's cross? The cross-section test involves creating a grid of parallel and perpendicular cross-sections according to ISO 2409 or ASTM D3359 standards. The St. Andrew's cross, on the other hand, forms an X. It is used when the geometry of the part or the thickness of the coating makes cross-sectioning difficult or impractical. What standards apply to these tests? The most common methods are: - ISO 2409: determination of adhesion by cross-cutting - ASTM D3359: cross-cut test (Method A or B) - ISO 16276-2: evaluation of the adhesion of protective coatings by mechanical tests, including cross-cutting Can these tests be carried out on all materials? Yes, as long as the coating is inciseable. They are suitable for metals, polymers, composites, coated ceramics, and most painted or varnished parts. Some very flexible or highly textured surfaces may require an adaptation of the method. How is the adhesion classification read? ISO 2409 assigns a class from 0 (very good adhesion) to 5 (significant delamination). ISO 16276-2 can incorporate acceptance criteria specific to corrosion protection systems. Is adhesive tape mandatory? Yes, for ISO 2409 and ASTM D3359. For the St. Andrew's cross or ISO 16276-2 assessments, use depends on the level of requirement or internal procedure. Which sectors use these tests the most? Aeronautics, automotive, medical devices, cosmetics, energy, nuclear, luxury goods, transportation… All industries where the durability of a coating is critical.