The Language of Finishing: Paint and Coatings Glossary P–Q

This installment of the AirSprayTech.com Paint and Coatings Industry Glossary covers terms beginning with P and Q. These definitions address liquid and powder application, plural-component equipment, surface preparation, corrosion protection, coating inspection, pressure equipment, quality assurance, quality control, and common coating defects.

Coating terminology can have different meanings depending on the industry, specification, manufacturer, or application process. Always consult the governing specification, approved product data sheet, safety data sheet, equipment manual, and complete referenced standard before performing coating work.

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P

Paint

Paint is a liquid, paste, or powder material applied to a surface to form a protective, decorative, identifying, or functional film. Paint may provide color, gloss, corrosion resistance, weathering resistance, chemical resistance, electrical insulation, fire protection, or other specialized properties.

In everyday use, the words “paint” and “coating” are often interchangeable. In technical work, “coating” is the broader term and includes primers, linings, clear coats, powder coatings, membranes, sealers, and other materials that may not ordinarily be called paint.

Paint Booth

A paint booth is an enclosed or partially enclosed area designed to control ventilation, overspray, vapors, contamination, and the movement of sprayed coating materials.

Booths may use crossdraft, downdraft, semi-downdraft, side-draft, or other airflow arrangements. They may be designed for liquid coating, powder coating, automotive refinishing, industrial finishing, or specialized processes.

A paint booth must be designed and operated as a complete system. Airflow, exhaust, replacement air, filters, electrical classification, lighting, grounding, fire protection, material characteristics, and applicable codes must all be considered.

Paint Kitchen

A paint kitchen is a designated room or controlled area used to store, mix, circulate, condition, and deliver coating materials to a finishing operation. It may contain pumps, pressure vessels, agitators, filters, regulators, color-change equipment, piping, and process controls.

Paint-kitchen design should address ventilation, spill containment, grounding, fire protection, material compatibility, labeling, housekeeping, and separation of incompatible products.

Paint Pump

A paint pump moves coating from a container, tank, drum, tote, or pressure system to one or more applicators. Common designs include diaphragm, piston, centrifugal, gear, and peristaltic pumps.

The correct pump depends on the material viscosity, required flow, pressure, number of guns, circulation needs, solids content, abrasiveness, solvent compatibility, shear sensitivity, and production schedule.

A pump should be selected by its ability to serve the process—not simply by physical size or maximum advertised pressure.

Paint System

A paint system is the complete combination of surface preparation and coating layers applied to a substrate. It may include pretreatment, primer, stripe coat, intermediate coat, finish coat, clear coat, lining, or specialized protective layers.

The performance of a paint system depends on the compatibility and proper application of every component. Substituting one layer without approval can change adhesion, cure, corrosion resistance, appearance, and service life.

Panel

A panel is a flat or formed test piece used to apply, cure, inspect, or compare a coating. Panels may be produced from steel, aluminum, plastic, wood, glass, concrete, or another representative substrate.

Test results can be affected by panel composition, thickness, preparation, surface profile, coating thickness, application method, and cure. A laboratory panel may not reproduce every condition found on an actual structure or production part.

Pass

A pass is one movement of a spray gun, roller, brush, blasting nozzle, or other application tool across an area. Multiple passes may be needed to produce one complete coat.

A spray pass should normally be straight, controlled, and overlapped consistently with the preceding pass. Arcing the gun can create heavy film in the center and light film at the edges.

Passivation

Passivation is a chemical or electrochemical process that makes a metal surface less reactive and more resistant to corrosion. It may occur naturally through oxide formation or be produced through a controlled treatment.

Passivation is commonly associated with stainless steel, aluminum, zinc, and other metals. The process must be compatible with the intended coating system. A passive surface that is too smooth or chemically unsuitable may require additional preparation before coating.

Pattern

A spray pattern is the shape and distribution of atomized coating leaving a spray gun and depositing on the target. Common patterns include round, oval, and elongated fan patterns.

A good pattern has reasonably uniform material distribution for the intended application. Heavy top or bottom, split, crescent-shaped, pulsing, or one-sided patterns may indicate incorrect setup, contamination, worn parts, air-cap obstruction, pressure imbalance, or an unsuitable nozzle combination.

Pattern-Control Valve

A pattern-control valve adjusts the airflow used to shape the spray pattern of many air spray and HVLP guns. Opening the valve generally widens the fan, while closing it moves the pattern toward a smaller or rounder shape.

The valve should not be used to compensate for a dirty or damaged air cap. Pattern shape also depends on the air cap, fluid nozzle, coating viscosity, atomizing pressure, fluid delivery, and gun distance.

Peak Density

Peak density is the number of surface-profile peaks within a defined distance or area. It provides information about the frequency of peaks rather than only their height.

Two blast-cleaned surfaces can have similar average profile depth but different peak densities. Peak density can influence coating adhesion and resistance to corrosion undercutting.

Surface-profile requirements should identify the measurement method and acceptance criteria. ASTM D4417 includes field methods for evaluating the profile of blast-cleaned steel.

Peeling

Peeling is the separation of a coating from the substrate or another coating layer in sheets, strips, or flakes. It represents a substantial loss of adhesion.

Common causes include contamination, inadequate surface preparation, incompatible coatings, moisture intrusion, exceeded recoat intervals, poor cure, excessive film stress, and coating over a weak existing layer.

Examining both sides of the detached film can help identify where separation occurred. The location of the failure is often more informative than the size of the peeled area.

Pencil Hardness

Pencil hardness is a relative measurement of a coating film’s resistance to scratching or gouging by drawing leads of known hardness.

The pencil scale progresses from softer grades, identified with B numbers, through HB and F, to harder grades identified with H numbers. Results can vary with the pencil manufacturer, test panel, coating thickness, substrate hardness, cure, and operator technique.

A commonly referenced procedure is ASTM D3363, Standard Test Method for Film Hardness by Pencil Test. Pencil hardness should not be confused with impact resistance, flexibility, or abrasion resistance.

Permeability

Permeability is the degree to which a coating allows a gas, vapor, or liquid to pass through its film. All organic coating films are permeable to some extent.

Permeability can be affected by coating chemistry, film thickness, cure, temperature, defects, pigment loading, and the material attempting to pass through the film.

A coating with low water-vapor permeability may be desirable in one application but may trap moisture in another. Coating selection must consider the complete substrate and exposure condition.

Personal Protective Equipment — PPE

Personal protective equipment includes clothing and devices worn to reduce exposure to workplace hazards. Coating operations may require gloves, protective clothing, eye protection, face protection, hearing protection, safety footwear, head protection, fall protection, or respiratory protection.

PPE is selected after evaluating the material, application process, exposure route, concentration, work area, and task. One glove, respirator cartridge, or coverall type is not suitable for every coating operation.

PPE does not replace ventilation, containment, substitution, equipment guards, or safe work procedures. General requirements are available from OSHA’s Personal Protective Equipment resources.

pH

pH is a numerical expression of how acidic or alkaline an aqueous solution is. A value of 7 is neutral under commonly referenced conditions, values below 7 are acidic, and values above 7 are alkaline.

pH is important in metal pretreatment, washing, rinsing, wastewater treatment, concrete evaluation, chemical cleaning, and waterborne coating processes.

The pH scale is logarithmic, so a change of one pH unit represents a tenfold change in hydrogen-ion activity. A surface pH reading should be obtained and interpreted using the specified method.

Phosphate Coating

A phosphate coating is a conversion layer formed on metal through chemical treatment. Iron phosphate, zinc phosphate, and manganese phosphate are common examples.

Phosphate pretreatment can improve coating adhesion, corrosion resistance, and process consistency. Performance depends on cleaning, bath control, contact time, temperature, rinsing, water quality, and the condition of the surface before coating.

Phosphating

Phosphating is the process used to form a phosphate conversion coating on a metal surface. It is common in OEM liquid finishing, powder coating, automotive manufacturing, appliances, metal furniture, and general industrial finishing.

A typical process may include cleaning, rinsing, conditioning, phosphating, additional rinsing, sealing, and drying. Chemical concentration, pH, temperature, spray pressure, contact time, and contamination must be controlled.

Pickling

Pickling is a chemical treatment, commonly using an acid solution, to remove oxides, scale, rust, or other surface material from metal.

After pickling, thorough rinsing, neutralization where required, drying, and protection from flash rust may be necessary. Residual acid or soluble contamination can cause severe coating failure.

Pickling involves significant chemical hazards and should be performed using an engineered and properly controlled process.

Pigment

Pigment is finely divided solid material dispersed within a coating to provide color, opacity, corrosion protection, reinforcement, texture, conductivity, ultraviolet resistance, or another property.

Pigments normally remain as part of the dried or cured coating film. They differ from dyes, which dissolve in the coating vehicle or solvent.

Pigments can settle during storage. A coating may require thorough mechanical mixing to restore uniformity before application.

Pinhole

A pinhole is a very small opening or pore extending into or through a coating film. Pinholes may expose the substrate and become initiation points for corrosion, leakage, or chemical attack.

Common causes include trapped air, outgassing, porous substrates, poor atomization, excessive film thickness, rapid solvent release, contamination, foam, or improper application over a rough profile.

Pinholes may be difficult to see during ordinary visual inspection. Holiday testing may be required for tank linings, pipeline coatings, containment systems, and other services requiring film continuity.

Plural-Component Coating

A plural-component coating is supplied in two or more separate components that chemically react after being combined. Common examples include epoxies, polyurethanes, polyureas, and high-build protective linings.

The components must be combined at the specified ratio. Incorrect proportioning or inadequate mixing can produce soft, brittle, weak, discolored, or incompletely cured material.

Plural-component coatings may be mixed in batches or proportioned automatically by specialized spray equipment. Fast-reacting products may have a usable mixed life of only seconds.

Plural-Component Spray Equipment

Plural-component spray equipment stores coating components separately and meters them at a controlled ratio. The components may be heated, pressurized, circulated, and mixed immediately before application.

The equipment may include proportioning pumps, heaters, heated hoses, ratio monitors, pressure sensors, flow meters, a mix manifold, static mixer, flush system, and specialized spray gun.

Correct operation depends on ratio assurance, balanced pressures, stable temperatures, suitable component viscosities, proper mixing, and effective flushing. Off-ratio material may appear acceptable when sprayed but fail to cure or perform properly.

Pneumatic Pump

A pneumatic pump is powered by compressed air. Air-operated diaphragm and piston pumps are commonly used to transfer, circulate, or pressurize coatings.

Pneumatic pumps are useful in finishing operations because their output can be controlled through air pressure and they do not require an electric motor at the pump. However, the complete installation must still address grounding, ventilation, material compatibility, pressure limitations, and hazardous-location requirements.

Polishing

Polishing is the controlled refinement of a cured coating surface to improve smoothness, gloss, clarity, or appearance. It may follow sanding or defect removal in automotive, aerospace, wood, and high-finish applications.

Polishing removes a small amount of material. Excessive polishing can thin the clear coat, expose underlying layers, round edges, generate heat, or produce swirl marks.

Polyester Powder Coating

Polyester powder coating is a thermosetting powder technology widely used for outdoor products, architectural components, metal furniture, automotive parts, agricultural equipment, and general industrial finishing.

Polyester powders are commonly selected for color retention and weathering resistance. Performance varies among formulations, so exterior suitability, chemical resistance, cure schedule, film thickness, and required durability must be confirmed from the product data.

Polyurethane Coating

Polyurethane coating is a broad category of coatings commonly selected for appearance, gloss retention, chemical resistance, abrasion resistance, flexibility, and weathering performance.

Many industrial polyurethane coatings are two-component systems consisting of a resin component and an isocyanate-containing hardener. Other polyurethane technologies include moisture-cure and waterborne systems.

Application requires attention to mix ratio, induction time, pot life, moisture, temperature, ventilation, and worker exposure. Consult the safety data sheet and current OSHA isocyanate guidance.

Porosity

Porosity is the presence of pores or voids in a substrate or coating. Concrete, cast metal, thermal-spray metal, wood, and certain coatings may contain substantial porosity.

Air, moisture, or gas escaping from pores during application or heating can cause bubbles, pinholes, craters, or holidays. Porosity can also allow liquids and contaminants to enter the substrate or coating system.

Sealers, penetrating primers, mist coats, preheating, vacuum impregnation, or modified application procedures may be used when approved for the substrate and coating.

Pot Life

Pot life is the period after mixing during which a multi-component coating remains suitable for application under stated conditions.

Pot life begins when the components are combined—not when spraying starts. It is affected by material temperature, batch size, coating chemistry, container shape, and surrounding conditions.

A coating can reach the end of its pot life without becoming visibly solid. Changes in viscosity, atomization, adhesion, cure, or film performance may occur before the material appears unusable.

Never add solvent or newly mixed material to expired coating in an attempt to restore its pot life unless the manufacturer provides a specific written procedure.

Powder Booth

A powder booth is an enclosure designed to contain airborne powder during electrostatic application and move oversprayed material toward a collection or recovery system.

Booth airflow must contain powder without pulling the spray pattern away from the workpiece. Filters, ductwork, recovery equipment, grounding, housekeeping, fire protection, and explosion protection are important parts of the complete system.

Powder Coating

Powder coating is a dry finishing process in which finely divided coating particles are applied to a surface and then melted or fused into a continuous film.

Most powder is applied electrostatically to a grounded metal part and cured with heat. Other methods include fluidized-bed application and processes using preheated components.

Powder coatings may be thermosetting or thermoplastic. Thermosetting powders chemically crosslink during cure, while thermoplastic powders melt and flow without the same type of crosslinking reaction.

Technical resources are available from the Powder Coating Institute.

Powder Feed Hopper

A powder feed hopper stores and conditions powder before it is delivered to an applicator. Many hoppers introduce low-pressure air through a porous membrane to fluidize the powder.

Properly fluidized powder behaves more like a liquid and can be delivered consistently through the feed system. Too little fluidizing air may cause surging or poor delivery, while too much air can create excessive dust, segregation, or unstable flow.

Powder Flow

Powder flow is the rate at which powder is delivered from the feed equipment to the applicator. It may be expressed by weight per unit of time, percentage setting, or another equipment-specific value.

Actual output depends on pump design, hose length and diameter, powder condition, injector wear, conveying air, supplemental air, fluidization, and restrictions.

Too much powder can reduce charging efficiency and penetration. Too little powder can lower production and produce inadequate film thickness.

Powder Reclaim

Powder reclaim is oversprayed powder collected for possible return to the application system. Reclaim can improve material utilization when the powder and process are suitable.

Recovered powder may differ from virgin powder because of particle-size separation, contamination, moisture, heat exposure, or repeated circulation. A controlled ratio of virgin and reclaimed powder may be required to maintain appearance and application performance.

Powder Recovery System

A powder recovery system separates oversprayed powder from booth exhaust air. Cyclones, cartridge collectors, filters, or combinations of equipment may be used.

The recovered material may be reused or collected for disposal. System design affects color-change time, collection efficiency, powder cleanliness, airflow, housekeeping, and production economics.

Powder Surge

Powder surge is an unstable burst or pulse of powder from the applicator. It can produce uneven film thickness, spitting, heavy spots, poor penetration, and inconsistent appearance.

Common causes include poor fluidization, moisture-contaminated powder, worn injectors, restricted or excessively long hoses, excessive powder output, hose loops, unstable air pressure, and powder buildup inside the delivery system.

Preheat

Preheat is the controlled heating of a substrate or component before coating application. It may be used to remove moisture, reduce outgassing, improve flow, support fluidized-bed powder application, or help a coating reach the required film thickness.

Preheating can also create problems if the surface is too hot. The coating may dry before wetting, cure prematurely, discolor, produce excessive film build, or create an unsafe vapor condition.

Preparation Grade

A preparation grade is a defined level of surface cleanliness produced by a specified cleaning method. Examples include abrasive-blast, hand-tool, power-tool, waterjetting, and chemical-preparation grades.

The complete standard designation and edition should be stated. A preparation grade may address visible cleanliness without establishing surface-profile depth, dust level, soluble salts, or moisture.

Pressure Drop

Pressure drop is the reduction in air or fluid pressure as material moves through hoses, pipes, filters, regulators, fittings, valves, and other restrictions.

Pressure drop increases with flow rate, hose length, viscosity, restrictions, and small internal diameters. A gauge at the compressor or pump may therefore show adequate pressure while the spray gun receives too little pressure during operation.

Pressure Feed

Pressure feed uses controlled fluid pressure to deliver coating from a pressure pot, pump, tank, or regulated system to a spray gun.

It supports higher production rates, remote material supply, larger containers, and more consistent fluid delivery than many cup-fed arrangements. Fluid pressure and atomizing-air pressure can usually be adjusted separately.

Pressure Pot

A pressure pot is a sealed vessel that uses regulated compressed air to place coating under pressure and deliver it to a spray gun or other applicator.

Pressure pots have few moving parts and provide steady material delivery for many low- and medium-volume applications. They are available in different capacities, pressure ratings, materials, and configurations.

A pressure pot is a pressure vessel. It must not be opened, serviced, or filled until pressure has been isolated and completely relieved according to the manufacturer’s procedure.

Pressure Ratio

Pressure ratio describes the theoretical relationship between the air pressure supplied to an air-powered pump and the fluid pressure the pump can develop at stall.

For example, a nominal 30:1 pump supplied with 80 psi of air can theoretically develop approximately 2,400 psi of fluid pressure at stall. Actual dynamic pressure while spraying will be lower because of flow demand, friction, restrictions, and pump condition.

Pressure ratio does not identify flow capacity. Two pumps with the same ratio may have very different outputs per cycle.

Primer

Primer is the first coating applied to a prepared substrate as part of a coating system. Its functions may include adhesion, corrosion protection, substrate sealing, chemical resistance, or creation of a compatible surface for subsequent coats.

A primer is not automatically suitable for long-term exposure without a topcoat. Its permitted exposure time, recoat interval, weathering resistance, and compatibility must be confirmed.

Profile

Surface profile is the three-dimensional texture of a prepared surface. On abrasive-blast-cleaned steel, it is commonly described by the distance from surface peaks to valleys.

Profile helps create a mechanical key for coating adhesion. If it is too shallow, adhesion may be reduced. If it is too deep, profile peaks may receive inadequate coating coverage and become corrosion-initiation points.

One commonly referenced standard is ASTM D4417, Field Measurement of Surface Profile of Blast-Cleaned Steel.

Protective Coating

A protective coating is applied primarily to shield a substrate from corrosion, chemicals, water, weather, abrasion, ultraviolet exposure, heat, fire, or another damaging condition.

Protective coatings are used on bridges, tanks, pipelines, marine structures, industrial equipment, concrete, roofs, floors, railcars, aircraft, and other assets.

Long-term performance depends on correct coating selection, surface preparation, environmental control, application, film thickness, cure, inspection, and maintenance.

Pull-Off Adhesion Test

A pull-off adhesion test applies increasing tensile force perpendicular to a coating through a bonded loading fixture, often called a dolly. The result indicates the force reached and the location where the coating system or test assembly separated.

The numerical result alone does not completely describe the test. The report should identify the coating, substrate, tester, loading fixture, adhesive, scoring method, pull rate, environmental conditions, measured strength, and failure location.

ASTM D4541 applies to pull-off testing of coatings on metal substrates. Pull-off testing of coatings on concrete is addressed by ASTM D7234. The methods and results should not be treated as interchangeable.

See ASTM D4541, Pull-Off Strength of Coatings Using Portable Adhesion Testers.

Pulsation

Pulsation is a repeating fluctuation in coating flow or fluid pressure. It can appear as pattern movement, alternating heavy and light film, pressure-gauge movement, or visible surging at the spray gun.

Causes may include pump cycling, inadequate air supply, air entering the fluid system, blocked filters, restricted suction, worn packings, poor regulator performance, or inadequate pulsation dampening.

Purge

Purging is the controlled removal of coating, solvent, air, moisture, powder, gas, or another material from a system by displacing it with a different material.

Examples include flushing mixed plural-component coating from a hose, clearing powder from a delivery line, removing air from a fluid system, or ventilating an oven before ignition.

Purge procedures must account for chemical compatibility, pressure, waste collection, ventilation, static electricity, ignition hazards, and the equipment manufacturer’s instructions.

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Q

QA — Quality Assurance

Quality assurance is the planned system of procedures, responsibilities, documentation, training, and oversight used to provide confidence that the completed work will meet its requirements.

QA is process-oriented. It may include qualification requirements, approved procedures, inspection plans, hold points, document control, equipment-verification programs, audits, and corrective-action systems.

Quality assurance does not consist only of inspecting the final coating. It begins before work starts and continues through material receipt, surface preparation, application, inspection, repair, and closeout.

QC — Quality Control

Quality control includes the operational checks, measurements, tests, and corrective actions used to determine whether coating work meets the established requirements.

QC activities may include checking surface cleanliness, profile, soluble salts, ambient conditions, mix ratio, viscosity, spray pattern, wet-film thickness, dry-film thickness, cure, adhesion, holidays, color, gloss, and appearance.

Quality control is usually performed by or for the organization completing the work, although project responsibilities vary.

Qualification

Qualification is the documented demonstration that a person, procedure, coating system, piece of equipment, or facility can meet specified requirements.

Examples include applicator qualification, coating-system qualification, procedure qualification, inspector certification, and powder-coating facility certification.

Qualification should not be assumed to cover every substrate, product, application method, or service condition. The scope and limitations should be reviewed.

Qualification Panel

A qualification panel is a prepared and coated test piece used to demonstrate an applicator’s technique, a coating system’s performance, or a proposed application procedure.

The panel should represent the actual work as closely as practical, including substrate, surface preparation, coating materials, equipment, film thickness, cure, orientation, edges, welds, and difficult geometry.

Acceptance tests and required documentation should be established before the panel is produced.

Qualification Test

A qualification test is performed to establish whether a person, process, coating system, or piece of equipment can satisfy defined requirements before production or field work proceeds.

Qualification testing may include adhesion, corrosion resistance, chemical immersion, flexibility, impact, holiday detection, hardness, weathering, cure, or visual evaluation.

A passed qualification test does not eliminate the need for production quality control. Actual work conditions must remain within the qualified limits.

Quality Audit

A quality audit is a systematic review of procedures, records, equipment, personnel qualifications, process controls, and completed work to determine whether the quality system is being followed and is effective.

An audit differs from routine inspection. Inspection evaluates particular work or measurements, while an audit examines the broader system used to plan, perform, document, and improve the work.

Quality Plan

A quality plan defines how quality requirements will be achieved and documented for a coating project or production process.

It may identify responsibilities, approved procedures, inspection points, test methods, sampling frequency, acceptance criteria, reporting requirements, nonconformance handling, repairs, and final documentation.

Quality Record

A quality record provides evidence that a required activity, measurement, inspection, or decision occurred. Examples include inspection reports, batch records, environmental logs, calibration certificates, oven profiles, film-thickness readings, photographs, repair records, and approval signatures.

A useful record should be legible, dated, traceable to the work, and protected against unauthorized alteration or loss.

Quick-Change Color System

A quick-change color system is powder or liquid finishing equipment designed to reduce the time and labor required to change from one coating color to another.

The system may use smooth internal surfaces, automated purge cycles, replaceable feed components, dedicated hoses, cartridge collectors, cyclone recovery, or multiple color modules.

A fast color change must still prevent contamination. Even a small quantity of the previous color can produce visible specks or unacceptable appearance in the next finish.

Quick-Disconnect Fitting

A quick-disconnect fitting allows a hose, gun, regulator, or fluid component to be connected and disconnected without threading and unthreading the fitting each time.

The fitting must be rated for the maximum pressure, temperature, material, and service. Air-line quick connectors should not be assumed suitable for high-pressure fluid.

Small or restrictive quick-disconnect fittings can cause pressure drop and inadequate airflow. A disconnected fitting may also retain trapped pressure unless the system is properly relieved.

Quench

Quenching is the rapid cooling of a heated part using water, air, oil, or another controlled medium. It may be used in metal processing, pretreatment, heat treatment, and certain finishing operations.

A quench can affect surface chemistry, retained moisture, cleanliness, part temperature, and readiness for coating. Water quality and contamination must be controlled when the quench is part of a coating process.

QUV Accelerated Weathering Tester

QUV is a trade name associated with accelerated weathering equipment manufactured by Q-Lab. The equipment uses fluorescent ultraviolet lamps and controlled moisture exposure to reproduce selected weathering stresses under laboratory conditions.

Testing may be used to compare changes in gloss, color, chalking, cracking, strength, and other properties. Results depend on lamp type, exposure cycle, temperature, condensation or water spray, specimen preparation, and evaluation method.

Accelerated test hours should not be converted into outdoor years using a universal formula. Correlation depends on the material, property being measured, exposure environment, and test cycle.

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Referenced Standards and Industry Resources

• AMPP Standards and Technical Resources
• Powder Coating Institute
• OSHA Personal Protective Equipment
• OSHA Isocyanates Safety and Health Information
• ASTM D3363 — Film Hardness by Pencil Test
• ASTM D4417 — Field Measurement of Surface Profile
• ASTM D4541 — Pull-Off Strength of Coatings
• ASTM D5162 — Holiday Testing of Protective Coatings on Metallic Substrates
• ASTM G62 — Holiday Detection in Pipeline Coatings

Continue Building Your Coatings Vocabulary

Understanding coatings terminology helps applicators, inspectors, equipment operators, specifiers, facility owners, and purchasing professionals communicate more accurately. Continue with the next installment of The Language of Finishing for definitions beginning with the letters R and S.

For assistance selecting professional spray guns, pumps, pressure equipment, powder coating systems, electrostatic equipment, spray booths, ovens, or genuine replacement parts, contact AirSprayTech.com—The Finishing Authority® at 817.490.1777.

Copyright © 2026 Azimuth Spray Systems, LLC. All rights reserved. AirSprayTech.com—The Finishing Authority®. No portion of this glossary may be reproduced, distributed, or republished without prior written permission.

Tags: paint coatings glossary P-Q, powder coating terminology, plural-component coatings, paint application terms, pressure pot systems, pinhole coating defects, protective coating terms, quality assurance coatings, quality control inspection