RODER · Inspection · Dimensions and geometry
Coating thickness
Measuring the thickness of coatings, paints and surface treatments is an indispensable quality check in many industrial sectors: industrial painting, corrosion protection, galvanising, chromium plating, anodising, polymer coatings. Alongside thickness verification, surface inspections comprise measurement of the blast profile (peak-to-valley), of contamination by soluble salts and dust, of coating adhesion and of the climatic conditions during application. The technologies used are predominantly non-destructive and portable, so that inspections can be carried out on site and on the paint line.
On this page
What the measurement is for: coating thickness ↑ up
The main applications are in the anti-corrosion painting of metal structures (bridges, tanks, ships, offshore platforms), in industrial coatings for the automotive and railway sectors, in galvanising, anodising and chromium plating processes, in heavy steelwork, and in the maintenance of chemical and petrochemical plants, where assessing the condition of the coating is critical for the service life of the structure. Post-application checks must be documented for compliance with specifications and for the coating warranty.
Coating thickness technologies ↑ up
DFT (Dry Film Thickness) gauges measure the dry thickness of paints and coatings on metal substrates. On ferrous substrates the magnetic pull-off principle or magnetic induction is used (variation of the magnetic field as a function of the distance from the substrate); on non-ferrous substrates (aluminium, copper, brass) the principle is eddy current, measuring the change in impedance of a high-frequency coil close to the substrate. Combo instruments identify the substrate automatically. For wet film (WFT), calibrated notched combs are used: simple and indispensable for checking during application.
Blast profile and contamination ↑ up
Preparing the metal surface before painting requires verification of the peak-to-valley roughness profile (Ry or Rmax), which is decisive for the adhesion of the coating. The most widespread methods are replica tape in accordance with ISO 8503-5 (with dedicated micrometers) and the visual/tactile comparators of ISO 8503-1. Surface contamination by soluble salts (chlorides, sulphates) is measured with the Bresle method (ISO 8502-6, ISO 8502-9), which uses adhesive cells together with conductivity meters or ion chromatography. Residual dust after blasting is covered instead by ISO 8502-3 (dust tape test).
Categories in this section ↑ up
The section comprises DFT gauges (magnetic and inductive/eddy current), combs for wet film WFT, instruments for blast profile and replica tape, thickness gauges for asphalt and building materials, adhesion tests (pull-off, cross-hatch), reference and calibration standards, and kits for measuring soluble salts and surface contamination. All the instruments are designed to be portable and usable on site.
Reference standards ↑ up
DFT coating thickness gauges are governed by ISO 2178 (magnetic), ISO 2360 (eddy current) and ISO 19840 for the statistical assessment of measurements on large surfaces. Wet film follows ISO 2808-1. Pull-off adhesion is covered by ISO 4624 and ASTM D4541. Surface preparation is described by the ISO 8501-1/2/3/4 series (grades of visual cleanliness) and ISO 8503 (profile roughness). Calibration of the gauges uses ISO 17025 certified shims of known thickness together with dedicated reference substrates. The child pages examine each family in more detail.
Documentary management of the measurements (with photographic reports, GPS recording of the sampling position, acceptance statistics) is today required by many specifications and forms an integral part of the qualification process. The most modern instruments offer Bluetooth/Wi-Fi interfaces and dedicated apps for automatic data export and the generation of reports that comply with the standards of the sector.
The pages in this section ↑ up
The in-depth pages for this quantity: techniques, selection criteria and instrument families.
Thickness gauges for dry film on metals (ferrous/non-ferrous): magnetic pull-off, inductive, eddy current.
In depth
Wet film thickness gauges (WFT)
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Combs and notched instruments for measuring the thickness of paint and coatings while still wet.
In depth
Blasting profile and replica tape
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Instruments for measuring the peak-to-valley profile of blasted surfaces, and micrometers for replica tape.
In depth
Coating adhesion testing
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Pull-off testers, cross-hatch testers and instruments for checking the adhesion of paints and coatings.
In depth
Salt, dust and surface contamination
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Instruments for measuring soluble salts (Bresle) and blasting residues on surfaces before painting.
Non-destructive instruments for measuring the thickness of road asphalt and building materials.
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Calibration samples for coating thickness gauges, surface profile instruments and accuracy verification.
The information on this page is provided for information purposes. Although it has been compiled with the greatest care, it may contain transcription errors or typos: for precise, up-to-date information please contact RODER SRL directly.
Contacts & Information
Contact for general information : info@roder.it
Machine Vision Division of RODER : www.visiotronix.com
RODER Instruments Division : www.innovacheck.com
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The information contained in this website is provided for information purposes only. Although it has been prepared with the greatest care, it does not constitute a contractual offer or a binding commitment to supply. It may contain transcription, translation or typographical errors. For precise and up-to-date information, please contact our company directly.
Note: Some images on this website have been intentionally generated using artificial intelligence (AI). This is because, for many applications and projects, photographs of the actual installation or system cannot be disclosed owing to confidentiality agreements, contractual clauses and non-disclosure agreements (NDAs).
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