CoatMentorCoating inspection, explained

Learn coating inspection

The concepts behind every coating inspector exam, in plain words, with the standards, defects and calculators that go with them. Free, no sign-up.

Guides15 longer reads: how to get each certificate, how the exams compare and the key standards. Exam-day sheetsOne printable page per exam: CIP Level 1, CIP Level 2 and FROSIO. Standards library60 standards in plain words: what each covers and how inspectors use it. Defects atlas40 coating defects with cross-sections, causes, prevention and repair. Glossary109 terms, each linked to the page that explains it. CalculatorsDew point, WFT ↔ DFT, DFT acceptance and more.

Surface preparation

Surface cleanliness gradesRust grades A–D, the Sa and St preparation grades and their SSPC/NACE counterparts, and what staining each grade allows.Surface profile (anchor pattern)Surface profile is the roughness blasting leaves on steel. Why coatings need it and how comparators, replica tape and depth gauges measure it.Soluble salts and the Bresle testWhy invisible salts under a coating cause blisters, how the Bresle patch and conductivity measure them, and what the inspector records.Waterjetting and flash rustThe WJ-1 to WJ-4 cleaning grades, why waterjetting exposes but does not create profile, and the light, medium and heavy flash rust grades.

Conditions and application

Dew point and the 3 °C marginWhat the dew point is, why steel must be at least 3 °C above it before blasting and coating, and how inspectors measure it.Volume solids, wet film and dry filmVolume solids links the wet film you apply to the dry film you get. The formula, the thinner correction and the spreading rate.Pot life and induction timeThe difference between pot life and induction (sweat-in) time for two-component coatings, and why mixing ratios matter.Drying, curing and recoat windowsTouch dry is not cured. How temperature and humidity change cure, what a recoat window is, and how inspectors check cure.Stripe coatsWhy edges, welds, corners and bolts get an extra brushed coat, and how inspectors check it.

Inspection and testing

Dry film thickness measurementHow DFT gauges work, how they are verified, and how SSPC-PA 2 and ISO 19840 sample and accept the readings.Holiday (discontinuity) testingWhat holidays are, how low-voltage wet-sponge and high-voltage DC detectors find them, and how film thickness decides which one to use.Adhesion testingPull-off adhesion (ISO 4624, ASTM D4541) and tape tests (ISO 2409, ASTM D3359): when each is used and how results are reported.

Coatings and corrosion

Protective coating typesHow the common protective coating families cure and why, with the strengths, weaknesses and typical use of each, from zinc primers to polyurea.Zinc-rich primersHow zinc protects steel galvanically, why zinc silicate needs moisture to cure, and how inorganic and organic zinc primers differ.Corrosivity categories (ISO 12944-2)How a corrosivity category (C1 to CX, Im1 to Im4) is decided under ISO 12944-2, what it changes on site, and why durability is no guarantee.Galvanic corrosionWhy two different metals in contact corrode, why the area ratio matters, and how design and coating prevent it.Cathodic protection basicsSacrificial anodes and impressed current, why cathodic disbondment happens, and how CP and coatings work together.

The inspector's job

Reference (control) areasWhy a small area prepared and coated to the agreed standard settles disputes on the whole job.Hold points, witness points and the ITPWhat an inspection and test plan lists, and the difference between a hold point and a witness point.Reports, nonconformances and traceabilityWhat a daily inspection report records, how a nonconformance report is closed, and why instrument serial numbers matter.

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Also: Concepts · Standards · Defects atlas · Glossary · Calculators · Guides.