AMPP CAS-1 key terms

The roughness profile produced on a substrate by abrasive blasting, measured as the average peak-to-valley height and depth of the surface. It gives the coating a mechanical key for adhesion.

A surface preparation method in which abrasive particles are propelled at high velocity against a substrate to remove rust, mill scale, old coatings, and contamination while creating a roughened profile.

A standardized visual rating of how completely blasting has removed rust, scale, and coatings from a steel surface, such as the near-white and white-metal grades used in specifications.

A reference tool, often a plate or disc with known roughness depths, pressed against or viewed beside a blasted surface to estimate the anchor pattern by touch or sight.

A thin, brittle oxide layer formed on steel during hot rolling. It is cathodic to steel, so if left in place it can promote localized corrosion and coating disbondment under a coating.

Light surface rusting that forms on a freshly blasted steel surface exposed to humid air. It must be removed before coating because it weakens adhesion.

Chlorides, sulfates, and other ionic salts left on a surface after preparation. They draw moisture, promote corrosion, and cause blistering or premature coating failure, so they are tested and limited.

A field method for soluble salts in which a surface is wetted or swabbed and the resulting solution's electrical conductivity is measured; higher conductivity indicates more dissolved ionic contamination.

The temperature at which air must cool for water vapor to condense. Coating work is restricted when the substrate is near or below dew point to avoid moisture on the surface.

The amount of water vapor in air expressed as a percentage of the maximum the air could hold at that temperature. It affects drying, curing, and the risk of surface moisture.

The temperature of the surface being coated, measured directly rather than taken from air temperature. It governs dew point margin, coating application, and cure behavior.

The combined ambient factors-air and substrate temperature, humidity, dew point, wind, and precipitation-that must be within the coating manufacturer's limits before, during, and after application.

The thickness of a coating measured immediately after application while still wet. It is checked with a comb or wheel gauge to confirm the applicator is on track to reach the specified dry film thickness.

The thickness of the fully dried or cured coating film, measured with magnetic or eddy-current gauges. It is the primary acceptance criterion for coating thickness in most specifications.

A unit of length equal to one thousandth of an inch (0.001 in), commonly used in the protective coatings industry to express wet and dry film thickness and profile depth.

An instrument, typically magnetic or eddy-current, that measures dry film thickness on a substrate. Readings are averaged and compared against specification limits and manufacturer tolerances.

A discontinuity, pinhole, void, or thin spot in a coating film that exposes or nearly exposes the substrate. Holidays are located with a high-voltage or low-voltage detector and must be repaired.

A device that applies a voltage across a coating to reveal discontinuities. High-voltage testers suit thick films; low-voltage (wet sponge) testers suit thin films and conductive substrates.

A tiny hole or pore through a coating film, often caused by trapped solvent, air, or surface contamination. It can expose the substrate to moisture and initiate corrosion.

A field or laboratory method, such as pull-off or cross-cut, that measures how strongly a coating bonds to the substrate or to the previous coat, confirming surface preparation was adequate.

An adhesion test in which a dolly is bonded to the coating and pulled perpendicularly until failure; the force at failure and the failure location are recorded.

Bonding of a coating to a substrate achieved by the coating penetrating the pores and roughness of the surface, interlocking physically rather than through chemical attraction.

The systematic verification of surface preparation, environmental conditions, application, and cured film properties against a specification, documented with readings and records.

Planned checks and measurements used to confirm work meets specification requirements, including hold points, testing, and acceptance criteria applied during each stage of coating work.

A stage in the work where the next step cannot proceed until a specified inspection or approval has been completed and documented, preventing covered-up defects.

Checking and adjusting an inspection instrument against a known standard or reference so its readings are accurate and traceable before use in acceptance testing.

An extra coat brushed into edges, welds, corners, and other hard-to-reach areas before or during the main coat, ensuring adequate film where spray coverage is typically thin.

Applying a subsequent coat over a previous one within the manufacturer's recoat window. Applying outside that window can cause poor intercoat adhesion and may require surface abrading.

The time interval after application during which the next coat may be applied without special surface treatment. Missing it can require abrading or solvent wiping.

The bond between successive coats of a coating system. It depends on proper surface preparation, recoat timing, and freedom from contamination between layers.

The chemical or physical process by which a coating hardens and develops its protective properties after application. Temperature, humidity, and film thickness all influence cure rate.

Trapping of solvent within a coating film, often from applying too thick a coat or recoating too soon, leading to pinholes, blistering, or soft films.

Blistering caused when water passes through a coating and dissolves soluble salts or impurities at the interface, drawing more water in and lifting the film from the substrate.

Systems such as harnesses, lanyards, guardrails, and anchor points used to prevent or arrest falls when working at height, a leading hazard in coating and blasting work.

A controlled procedure for entering tanks or vessels with limited access and poor ventilation, requiring atmospheric testing, permits, attendants, and rescue provisions before entry.

Supplying and exhausting air to control dust, solvent vapor, and oxygen levels in work areas, protecting workers and keeping concentrations below exposure limits and flammability ranges.

Gear worn to reduce exposure to hazards, such as blast hoods, respirators, eye protection, gloves, and protective clothing, selected based on the task and exposure assessment.

Abrasive and removed material generated during blasting. It may contain heavy metals or silica and is managed as a waste stream under environmental regulations.

The handling, storage, labeling, and disposal of wastes such as spent abrasive, solvent, and paint residue in accordance with applicable environmental rules and site plans.

Organic solvents and other carbon-based compounds that evaporate from coatings and thinners. They are regulated for air quality and worker exposure, influencing coating selection and application.