The Language of Finishing: Paint and Coatings Glossary N–O

This installment of the AirSprayTech.com Paint and Coatings Industry Glossary covers terms beginning with N and O. These definitions address coating application, spray equipment, protective coatings, OEM finishing, powder coating, surface preparation, industrial safety, coating defects, oven curing, inspection, and quality control.

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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N

NACE International

NACE International was a professional organization devoted to corrosion prevention and control. It developed standards, training programs, certifications, and technical resources covering protective coatings, linings, cathodic protection, materials selection, and corrosion management.

NACE International and SSPC: The Society for Protective Coatings combined to form AMPP—the Association for Materials Protection and Performance. Many existing project specifications and product data sheets still refer to NACE or SSPC standards by their former designations.

A legacy reference to a NACE standard should not be discarded or casually replaced. The exact designation, title, edition, and any current AMPP designation should be verified. Learn more through AMPP’s history of NACE International.

Natural Weathering

Natural weathering is the exposure of a coating, test panel, or material to actual outdoor conditions for a specified period. It may be used to evaluate color change, gloss loss, chalking, cracking, corrosion, erosion, and other forms of degradation.

Results depend heavily on location, orientation, exposure angle, sunlight, temperature, humidity, rainfall, salt, pollution, and duration. Natural weathering results from one climate should not automatically be applied to a substantially different environment.

Near-White Metal Blast Cleaning

Near-white metal blast cleaning is a high degree of abrasive-blast surface preparation used for steel in demanding protective coating service. It removes visible oil, grease, dust, dirt, mill scale, rust, coating, oxides, corrosion products, and other foreign matter, except for limited staining permitted by the standard.

The commonly referenced joint standard is SSPC-SP 10/NACE No. 2, now maintained through AMPP. The prepared surface must also meet the project’s requirements for surface profile, dust, soluble salts, and environmental conditions.

A visual cleanliness grade does not by itself establish that the required anchor profile or soluble-salt limit has been achieved. Current standards are available from AMPP.

Needle Gun

In coating work, a needle gun generally means a pneumatic needle scaler containing multiple hardened steel needles that rapidly strike the surface. It is used to remove loose rust, mill scale, weld slag, and deteriorated coating from steel.

Needle guns are helpful around welds, bolts, corners, irregular surfaces, and areas that are difficult to reach with larger tools. They may also produce a surface profile, depending on the substrate, needle design, and operating technique.

Needle scaling can generate noise, vibration, flying debris, and hazardous dust. Appropriate containment, hearing protection, eye and face protection, respiratory controls, and evaluation of the existing coating are important.

Needle Scaler

A needle scaler is a hand-held power tool that uses a bundle of reciprocating metal needles to clean and texture metal surfaces. The terms needle scaler and needle gun are frequently used interchangeably in maintenance painting and surface preparation.

The tool is useful for localized preparation but may not be efficient for large areas. The resulting surface must be inspected to confirm that it satisfies the specified cleanliness and profile requirements.

Negative Air Pressure

Negative air pressure exists when the pressure inside an enclosure is lower than the pressure outside it. Air therefore tends to flow into the enclosure instead of allowing contaminated air to escape through openings.

Negative pressure is commonly used in abrasive-blasting containment, hazardous-coating removal, dust-control enclosures, and certain spray operations. It helps control the release of dust, overspray, and contaminants.

A complete containment system also depends on adequate air volume, filtration, enclosure integrity, replacement air, pressure monitoring, and proper handling of collected waste.

Neutral Cleaner

A neutral cleaner is a cleaning material formulated to operate near the neutral portion of the pH scale. It may be selected when a strongly acidic or alkaline cleaner could damage the substrate, existing coating, sealant, or surrounding material.

The description “neutral” does not guarantee that a cleaner will leave no residue or that it is compatible with every coating system. The cleaned surface may require rinsing, drying, and inspection before coating.

Neutralization

Neutralization is the process of reducing or correcting unwanted acidity or alkalinity. It may be required after certain chemical-cleaning, stripping, concrete-preparation, or surface-treatment processes.

A surface that has been chemically treated should not be assumed ready for coating merely because it appears clean. Residual chemicals, reaction products, moisture, and soluble contamination may remain. The required rinsing and verification procedure should come from the coating or treatment manufacturer and the project specification.

NFPA — National Fire Protection Association

NFPA is an organization that publishes codes and standards addressing fire, electrical, explosion, and life safety. Coating operations may encounter NFPA requirements involving spray application, flammable liquids, combustible dust, ovens, ventilation, electrical equipment, grounding, and fire protection.

The applicable code depends on the process, facility, material, equipment, and jurisdiction. Compliance may also require coordination with the authority having jurisdiction, commonly abbreviated AHJ.

Information about NFPA codes and standards is available from the National Fire Protection Association.

NIOSH — National Institute for Occupational Safety and Health

NIOSH is a United States federal research agency focused on preventing work-related injury and illness. It publishes research, recommended exposure limits, respirator information, hazard evaluations, and technical guidance relevant to coating operations.

Coating professionals may consult NIOSH resources for information about solvents, isocyanates, metals, abrasive blasting, respirators, noise, and other workplace hazards.

NIOSH recommendations do not replace applicable OSHA regulations or an employer’s site-specific exposure assessment. Additional resources are available from NIOSH.

Nitrile Glove

A nitrile glove is made from a synthetic rubber material commonly used for hand protection in coating, maintenance, cleaning, and mixing operations.

Nitrile provides resistance to many oils and chemicals, but no glove material protects against every coating, solvent, hardener, or exposure duration. Thin disposable gloves can also be damaged by abrasion, puncture, extended contact, or repeated use.

Glove selection should be based on the safety data sheet, chemical-resistance information from the glove manufacturer, expected contact time, glove thickness, work activity, and need for dexterity.

Nozzle

A nozzle is a component that directs or controls the flow of air, coating, abrasive, water, or another material. The term has different meanings depending on the equipment.

On an air spray gun, the fluid nozzle meters and directs liquid coating toward the air cap. On abrasive-blasting equipment, the blast nozzle accelerates and shapes the abrasive stream. On other systems, “nozzle” may refer generally to the complete discharge assembly.

The correct nozzle must be selected for the material, production rate, desired pattern, equipment pressure, and finish quality. A worn nozzle can change flow, atomization, pattern shape, and material consumption.

Nozzle Orifice

The nozzle orifice is the opening through which coating, abrasive, air, or another material passes. Orifice size is one of several factors controlling flow.

A larger fluid orifice generally permits higher material flow or allows passage of higher-viscosity material, but actual output also depends on pressure, viscosity, hose restrictions, needle travel, equipment design, and material density.

Orifice measurements may be stated in inches, millimetres, or manufacturer-specific codes. The operator should not assume that identically numbered parts from different equipment systems have the same dimensions.

Nozzle Size

Nozzle size identifies the dimensions or capacity of a spray, fluid-delivery, or abrasive-blasting nozzle. In air spray equipment, it commonly refers to the fluid nozzle’s orifice diameter. In airless spraying, the spray tip size normally includes both orifice and fan-width information.

Selecting a nozzle that is too small may restrict flow or require excessive pressure. A nozzle that is too large can produce excessive material delivery, poor control, heavy film, runs, or equipment demands beyond the pump’s capacity.

Nominal Dry-Film Thickness

Nominal dry-film thickness is the stated or intended dry thickness of a coating layer or system. It may be used as a design value, target, or general description.

“Nominal” should not be assumed to define the complete acceptance criteria. A specification should identify the permitted minimum, maximum, averaging procedure, number of readings, measurement method, and treatment of individual high or low values.

Nominal Pipe Size — NPS

Nominal Pipe Size is a standardized designation used to identify pipe size. It is not necessarily the pipe’s exact inside or outside diameter.

NPS can be relevant when estimating coating area, selecting internal pipe-coating equipment, planning inspection, or calculating material requirements. Pipe schedule and actual dimensions must be considered when accurate measurements are required.

Nonconductive Coating

A nonconductive coating resists the flow of electrical current. Most conventional organic coatings become electrically insulating after they form a continuous film.

In electrostatic application, a nonconductive coating layer can reduce the ability of subsequently applied charged material to transfer its electrical charge to ground. Excessive coating thickness may therefore reduce electrostatic attraction and contribute to back-ionization or poor deposition.

Nonferrous Metal

A nonferrous metal is a metal or alloy in which iron is not the principal constituent. Common examples include aluminum, copper, brass, bronze, zinc, magnesium, and titanium.

Nonferrous metals require preparation and pretreatment appropriate to the particular alloy and service. A method suitable for carbon steel may damage a softer metal or fail to provide adequate adhesion.

Oxide removal, cleaning, conversion coating, surface profile, and the interval between preparation and coating can strongly influence performance.

Non-Sag Coating

A non-sag coating is formulated to resist running or sagging when applied to vertical or overhead surfaces at the recommended thickness.

The term does not mean the material can be applied at unlimited thickness. Excessive film build, improper thinning, high material temperature, incorrect spray setup, or slow application can overcome the coating’s sag resistance.

Nonskid Coating

Also called: Non-slip coating or slip-resistant coating.

A nonskid coating system produces a textured surface intended to improve traction. It is commonly used on walkways, stairs, decks, ramps, factory floors, marine surfaces, aircraft, and transportation equipment.

Texture may be created by broadcasting aggregate, mixing aggregate into the coating, using a textured roller, or applying a purpose-formulated material. Performance depends on aggregate size, distribution, film thickness, cleanability, wear, contamination, and service conditions.

Describing a coating as nonskid does not establish a specific coefficient of friction. If measurable slip resistance is required, the governing test method and acceptance value must be specified.

Nonvolatile Content

Nonvolatile content is the portion of a coating that remains after specified volatile material has been removed under defined test conditions. It may be reported by weight or by volume.

Nonvolatile content by volume is commonly called volume solids and is used to estimate the relationship between wet-film and dry-film thickness. Nonvolatile content by weight is not interchangeable with volume solids because coating ingredients have different densities.

One relevant method is ASTM D2369, Standard Test Method for Volatile Content of Coatings. ASTM identifies the weight percentage of nonvolatile matter as a value that may be determined by difference under the test conditions.

Normal Spray Distance

Normal spray distance is the gun-to-work distance recommended for a particular spray technology, applicator, material, and part. There is no single correct distance for every spray gun or coating.

If the gun is held too far from the part, the result may be dry spray, overspray, poor transfer efficiency, and rough texture. If it is held too close, the spray pattern may not fully develop and the coating may run, sag, or build unevenly.

The applicator should maintain a consistent distance and keep the spray gun perpendicular to the surface unless part geometry requires a controlled change in angle.

NORSOK M-501

NORSOK M-501 is a coating standard widely associated with surface preparation and protective coating systems for offshore and related industrial facilities.

The standard addresses subjects such as coating-system selection, surface preparation, application, inspection, qualification, and documentation for demanding environments.

A general statement that a product is “NORSOK approved” should be examined carefully. The applicable system, substrate, service area, qualification testing, film thickness, and current edition must be identified. Information about NORSOK standards is available from Standards Norway.

Nylon Powder Coating

Nylon powder coating is a thermoplastic coating used where abrasion resistance, impact resistance, low friction, chemical resistance, or a smooth protective surface is needed.

Applications may include wire products, racks, appliance components, medical equipment, automotive parts, tools, valves, and material-handling equipment.

Because it is thermoplastic, nylon powder melts and flows with heat rather than curing through the same type of crosslinking reaction used by thermoset powders. Preheating, fluidized-bed coating, electrostatic spray, and post-heating may be used depending on the product and process.

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O

OEM — Original Equipment Manufacturer

An original equipment manufacturer produces equipment, components, vehicles, appliances, machinery, or other finished goods. OEM finishing refers to coating performed as part of the original manufacturing process rather than as later maintenance or refinishing work.

OEM coating operations often use automated or conveyorized pretreatment, liquid spray, powder coating, electrocoating, curing, inspection, and material-handling systems. Consistent color, appearance, film thickness, adhesion, corrosion resistance, and production rate are common requirements.

OEM Finish

An OEM finish is the coating system originally applied by or for the equipment manufacturer. It may include pretreatment, primer, surfacer, color coat, clear coat, powder coating, E-coat, or another engineered system.

Matching an OEM finish during repair may require more than matching color. Gloss, texture, film build, metallic orientation, corrosion protection, chemical resistance, and cure must also be considered.

Occupational Exposure Limit — OEL

An occupational exposure limit is a concentration or exposure level used to evaluate a worker’s exposure to a chemical or physical agent. The term may include enforceable limits and recommended guidelines issued by different organizations.

Examples include OSHA permissible exposure limits, NIOSH recommended exposure limits, and other professionally recognized values. These limits may use different averaging times, ceiling values, skin notations, and measurement methods.

Compliance cannot be established from odor or a visual observation. Exposure assessment and air monitoring should be performed by qualified personnel when required.

Oil Contamination

Oil contamination is the presence of unwanted oil, grease, lubricant, hydraulic fluid, compressor oil, cutting fluid, fingerprints, or similar material on a substrate or coating.

Oil can interfere with wetting, adhesion, cure, appearance, and corrosion protection. Abrasive blasting an oily surface may spread or drive contamination into the surface instead of removing it.

Visible oil and grease should generally be removed with an appropriate cleaning process before mechanical surface preparation. Compressed air used for blasting, spraying, and cleaning should also be checked for oil and moisture contamination.

Oil-Free Air

Oil-free air is compressed air that meets the process requirement for freedom from oil contamination. It may be required for spray atomization, abrasive blasting, breathing-air systems, instrumentation, powder coating, and sensitive OEM finishes.

The phrase does not necessarily mean that the compressor itself contains no lubricant. An air system may use separators, coalescing filters, dryers, and other treatment equipment to achieve the required air quality at the point of use.

Air quality should be evaluated where the hose connects to the process, not merely at the compressor.

One-Component Coating — 1K

A one-component coating is supplied ready for use without mixing a separate chemical hardener or activator into the product. It is often described as a 1K coating.

A one-component product may cure by solvent evaporation, water evaporation, oxidation, atmospheric moisture, heat, ultraviolet energy, or another mechanism. One-component does not necessarily mean that the coating is simple, low-performance, or ready to apply without mixing or adjustment.

Open Time

Open time is the period during which an applied material remains workable, receptive to joining, or capable of flowing into adjacent application areas. The exact meaning depends on the product and process.

For floor coatings and membranes, open time may affect the ability to maintain a wet edge. For adhesives or sealants, it may describe the period during which assembly can occur. Open time should not be confused with pot life, dry-to-touch time, or maximum recoat time.

Operating Pressure

Operating pressure is the pressure present while a spray gun, pump, blasting nozzle, or other device is functioning at its normal flow rate. It is different from static pressure measured when the equipment is not flowing.

Restrictions in hoses, filters, fittings, regulators, and valves can create substantial pressure loss during operation. For accurate setup, the measurement location and whether the reading is static or dynamic should be identified.

Orange Peel

Orange peel is a textured coating appearance resembling the surface of an orange. It occurs when the applied coating does not flow and level into the required smooth finish.

Possible causes include excessive viscosity, poor atomization, incorrect spray distance, unsuitable reducer, rapid solvent evaporation, low material flow, excessive airflow, incorrect fluid nozzle, improper oven conditions, or insufficient wet-film thickness.

Some amount of texture may be intentional or acceptable on certain OEM, powder-coated, architectural, or industrial surfaces. Acceptance should be based on an approved sample, appearance standard, or written requirement rather than personal preference alone.

Organic Coating

An organic coating contains a carbon-based binder such as epoxy, acrylic, alkyd, polyurethane, polyester, vinyl, or another polymer. Most paints and protective coating systems are classified as organic coatings.

The term distinguishes these materials from inorganic coatings such as certain silicate-bound zinc coatings. It does not mean that the coating is naturally derived, environmentally harmless, or certified for organic agriculture.

Osmosis

Osmosis is the movement of a solvent, often water, through a semipermeable film toward a region containing a higher concentration of dissolved material.

In coating systems, soluble contamination beneath or within a film can attract water through the coating. Pressure may then develop and contribute to blister formation or loss of adhesion.

Osmotic Blistering

Osmotic blistering occurs when water moves through a coating film toward soluble material at or near the substrate. The resulting pressure creates raised blisters and may eventually cause coating rupture or detachment.

Sources of soluble contamination include residual salts, cleaning chemicals, corrosion products, contaminated abrasive, process chemicals, and substances remaining in porous concrete.

The presence of water in a blister does not prove that osmosis was the only cause. Investigation should consider coating permeability, immersion conditions, surface preparation, moisture transmission, cure, and contamination.

Outgassing

Outgassing is the release of air, moisture, gas, or volatile material from a substrate or coating during application, heating, drying, or cure.

It is frequently encountered when coating porous castings, galvanized steel, concrete, wood, previously coated surfaces, and components containing trapped contaminants. Outgassing may produce bubbles, pinholes, craters, or ruptures in the film.

Possible controls include cleaning, preheating, applying the coating while the part is cooling, reducing film thickness, using an approved primer, adjusting oven conditions, or selecting a coating designed for outgassing resistance.

Over-Atomization

Over-atomization occurs when excessive atomizing energy breaks a liquid coating into droplets that are smaller than necessary for the application.

Common results include excessive overspray, dry spray, poor transfer efficiency, rapid solvent loss, rough texture, reduced gloss, color variation, and increased booth loading.

Possible causes include excessive atomizing-air pressure, excessive airless pressure, an unsuitable air cap or tip, low fluid delivery, low material viscosity, or excessive gun distance.

Overbake

Overbake occurs when a coating or coated part receives more heat exposure than permitted by the approved cure schedule. This may result from excessive oven temperature, excessive dwell time, a production stoppage, or unexpected part-metal temperature.

Possible effects include discoloration, gloss change, embrittlement, adhesion loss, reduced flexibility, degradation of the substrate, or difficulty applying another coat.

Air temperature alone does not establish whether a coating has been overbaked. Actual part-metal temperature and time at temperature are often the controlling values.

Overcoat

An overcoat is a new coating applied over an existing coating system. Overcoating may extend service life, restore appearance, add film thickness, improve cleanability, or change color without completely removing the old coating.

A successful overcoat depends on the condition, adhesion, compatibility, cleanliness, thickness, and remaining service life of the existing system. Coating over a poorly adhered or actively deteriorating film can transfer the original weakness into the new system.

Overcoating

Overcoating is the process of applying a new coating over an existing coating or lining. It may include washing, contaminant removal, spot preparation, feathering, repairs, adhesion testing, and application of one or more additional coats.

Before overcoating, the existing film should be evaluated for adhesion, compatibility, chalking, brittleness, underfilm corrosion, soluble salts, moisture, and hazardous constituents.

A small test patch can provide useful information, but it does not guarantee long-term performance across an entire structure with varying conditions.

Overlap

Overlap is the portion of one spray pass, roller pass, or application section that covers part of the preceding pass. Consistent overlap helps maintain continuous coverage and uniform film thickness.

Approximately 50 percent overlap is a common spray technique, but the correct value depends on pattern shape, coating flow, gun speed, target thickness, and part geometry.

Poor overlap can create alternating heavy and light bands. Excessive overlap may produce runs, sags, solvent entrapment, or uneven appearance.

Overspray

Overspray is sprayed coating that does not deposit on the intended target or does not become part of the desired film. It may remain airborne, collect in the booth, settle onto adjacent surfaces, or land on a partially dried coating.

Causes include excessive atomization pressure, incorrect gun distance or angle, poor part positioning, an oversized spray pattern, excessive airflow, worn components, and failure to trigger the gun properly.

Overspray increases material consumption, filter loading, housekeeping, emissions, and contamination risk. Overspray landing on the work can also create dry spray, roughness, poor gloss, or intercoat adhesion problems.

Overspray Collection

Overspray collection is the capture and removal of coating material that does not deposit on the workpiece. Liquid spray booths commonly use dry filters, water wash systems, or other collection arrangements.

Powder booths may collect oversprayed powder for disposal or, where the process permits, recovery and reuse. Recovery must control contamination, particle-size changes, color carryover, and the ratio of reclaimed to virgin powder.

Oven

In finishing, an oven is an enclosed heated chamber used to dry, flash, gel, bake, or cure coatings and pretreatment residues. Ovens may use convection, infrared radiation, induction, or a combination of heating methods.

Oven design must consider the coating, substrate, part mass, production rate, solvent release, ventilation, exhaust, temperature uniformity, electrical classification, fire protection, and applicable codes.

A coating oven should not be operated as though it were simply a heated room. Safe concentration limits, interlocks, purge cycles, airflow, burner controls, and preventive maintenance are critical.

Oven Cure

Oven cure is the use of controlled heat to cause a coating to develop its required film properties. It is common in powder coating, automotive OEM finishing, appliances, metal furniture, E-coat, coil coating, and other production processes.

The cure schedule may be stated as a required part-metal temperature for a specified amount of time. The clock typically begins when the part reaches the specified temperature—not simply when it enters the oven.

Oven Dwell Time

Oven dwell time is the total period a part remains inside an oven. It should not automatically be treated as equivalent to cure time.

A portion of the dwell time may be required for the part to heat to the specified metal temperature. Part thickness, mass, shape, loading pattern, line speed, oven balance, and starting temperature all affect the heating rate.

Oven Profile

An oven profile is a recorded history of temperature over time as a coated part travels through an oven. A profiling instrument normally uses temperature probes attached to the part and, where appropriate, an air-temperature probe.

The profile shows heat-up rate, peak temperature, time at or above specified temperature, zone transitions, and cooling conditions. It can help identify cold spots, excessive heat, line-speed problems, airflow imbalance, and differences between heavy and light parts.

Overcure

Overcure occurs when a coating receives more curing energy, time, or temperature than the approved range. The term is closely related to overbake but may also apply to ultraviolet, infrared, moisture, or other curing processes.

Overcure can cause discoloration, brittleness, gloss change, reduced adhesion between coats, loss of flexibility, or degradation of the coating or substrate. Some products tolerate additional cure better than others.

Overfilm Thickness

Overfilm thickness means that the applied coating exceeds the permitted maximum dry- or wet-film thickness. Although additional coating may appear beneficial, excessive thickness can create significant defects.

Possible consequences include solvent entrapment, slow cure, sagging, wrinkling, cracking, mud cracking, delamination, reduced flexibility, excessive internal stress, and difficulty during assembly.

Acceptance must be based on the specification and coating manufacturer’s limits. An average thickness within range does not necessarily make an extreme individual high reading acceptable.

Oxidation

Oxidation is a chemical or electrochemical reaction involving the loss of electrons. In coating work, the term is commonly associated with metal corrosion, weathering of organic coatings, and the curing of certain alkyd or oil-based products.

Oxidation can produce rust on steel, oxide films on nonferrous metals, chalking, color change, embrittlement, or loss of coating properties. The effect may be harmful or may form part of an intended curing or pretreatment process.

Oxide

An oxide is a compound formed when oxygen combines with another element. Rust on steel consists largely of iron oxides and related corrosion products. Aluminum, zinc, and other metals also form oxide layers.

Some oxide films are relatively protective, while others are loose, porous, or unsuitable for coating. Preparation requirements depend on the substrate, oxide condition, coating system, and service environment.

Oxygen Inhibition

Oxygen inhibition is interference with a coating’s surface cure caused by contact with oxygen. It is most often associated with certain free-radical-cured materials, including some ultraviolet-cured coatings and polyester systems.

The affected surface may remain tacky, soft, or chemically underdeveloped even when the material beneath it has cured. Control methods depend on the coating chemistry and may include proper cure energy, film thickness, formulation-specific procedures, or use of an inert atmosphere.

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Referenced Standards and Industry Resources

• AMPP Standards and Technical Resources
• AMPP — History of NACE International
• National Institute for Occupational Safety and Health
• National Fire Protection Association Codes and Standards
• Standards Norway — NORSOK M-501
• ASTM D2369 — Volatile Content of Coatings
• ASTM D2832 — Volatile and Nonvolatile Content of Paint and Related Coatings
• OSHA Respiratory Protection

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 P and Q.

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 N-O, industrial coating terminology, NACE coating standards, nozzle selection, nonvolatile content, OEM finishing terms, orange peel coating defect, outgassing, overspray control