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Glossary and explanations

The definitions and explanations stated in this glossary are given in relation to paints and coatings. Themajority of the terms will have additional non-paint/coating related meanings.

AbrasionResistance

The ability of a coating to resist being worn away and to maintain itsoriginal appearance and structure when subjected to rubbing, scraping, orwear.

Abrasive A fine graded (sized) granular or spherical material, such as sand, steelgrit, steel shot, metallic oxide particles, minerals, which is used in a blastcleaning process or for abrasive cleaning.

Abrasive padsand discs

A non-woven synthetic fibre web material of continuous filamentsimpregnated with abrasive grit.

Absorption Process of soaking up, or assimilation of one substance by another.

Accelerator An additive that accelerates the reaction speed in curing of certaincoatings.

Acrylic resin A physically drying synthetic resin obtained by polymerising variousacrylic monomers either alone or in combination.

Additive A substance added in small quantities to paint formulations, its function being to improve certain properties of the paint or to facilitate its preparation. Examples are viscosity modifiers, anti-settling agents, anti-skin agents, dryers, etc.

Adhesion State in which two surfaces are held together by interfacial forces whichmay consist of valence forces or interlocking action, or both.

Air-dryingpaints

Paints, whose film hardens by evaporation of organic solvents or water,followed by reaction of the binder with oxygen in the air without anyexternal heat being applied. Drying oils, alkyds and epoxyesters are air-drying binders.

Airentrapment

Air bubbles included in paint film. May be caused by foam created byapplication equipment, or by air-inclusion in the paint during vigorousstirring prior to application. Some paints release air easier from the wetfilm than others. Those who dont may suffer from air entrapment in the

dry film (like a Swiss cheese). Protective properties will be reduced and possibility for blistering increased.

Airless spray A method of paint application by means of spray equipment that does notuse compressed air to atomise the paint. A pump delivers the paint at high

pressure (up to 5,000 psi) through a pressure hose to the spray gun. Whenreleased through the spray guns nozzle, the sudden drop in pressureatomises the paint, the droplets of which are carried to the surface bytheir momentum. The orifice size is chosen to suit the consistency of the

paint.

Aliphatichydrocarbon

Straight chain solvent of low solvent power, derived from petroleum.White Spirit used in alkyd paints is an aliphatic hydrocarbon.


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Alkali A substance that in water solution is bitter and is irritating or caustic tothe skin and mucous membranes, turns litmus blue, and has a pH valuegreater than 7.0. Examples: sodium hydroxide, sodium carbonate (sodaash), sodium chloride, sodium bicarbonate, and corresponding potassiumcompounds.

Alkalinecondition

Condition where there is an excess of hydroxyl ions. The pH will behigher than 7. May cause breakdown of paint whose binder is not alkalineresistant, e.g. alkyd paint.

Alkyd A synthetic resin binder made by reacting two chemicals in the presenceof natural or processed oil. They are the modern version of oil-paints,also some times incorrectly referred to as gloss finish. Alkyds can alsooften be characterised as fortified types of the original oil. There are awide variety of possible constituents; the most usual of which are drying

oil, fatty acids and alcohols. Alkyds can be tailor-made to meetdifferent conditions, such as flexibility, weathering, drying time, etc. Theyare mostly air-drying, curing through a reaction with oxygen in theatmosphere.

Alligatoring A type of crazing or surface cracking of a definite pattern in a coatingfilm, giving an appearance similar to that of an alligator hide. The effectis often the result of weather ageing of a coating. Also referred to asCrocodiling.

Ambient An encompassing atmosphere or surrounding environmental condition,such as temperature, relative humidity and pressure.

Amines Organic substituted ammonia, organic compounds having NH 2 or NHgroups. Curing agent for epoxy.

Amine adduct An amine curing-agent pre-reacted with a portion of epoxy.

Anchorpattern

Blast cleaning of steel will result in a certain roughness of the steelsurface (profile). This roughness creates a larger surface area on thesubstrate to be painted, which in turn will improve the adhesion of the

paint to the steel.

The higher the surface roughness, the better the adhesion. Profile depth isthe average distance between top of peaks and bottom of valleys. Peakdensity describes how dense the pattern is (number of peaks per area).Grit (angular blasting media) will give a better anchor pattern than shot(round blasting media).

Anode The positive electrode of an electrolytic cell, to which negatively chargedions travel when an electric current pass through the cell. In a primary cell(battery or fuel cell), the anode is the negative electrode. See alsoSacrificial Anode and Cathode.

Anodic area The positively charged area (metal surface) in corrosion cells wherecorrosion takes place. See also sacrificial anode.


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Antifouling Type of paints used on areas submerged in seawater. They are mostlyformulated in such a way that biocides gradually leach out and affect athin layer of water close to the paints surface, preventing the marineorganisms (fouling) to settle and develop on the painted surface.

Aromatichydrocarbon

Solvent containing the cyclic benzene ring having high solvent power e.g.xylene.

Artificialageing

A procedure designed to accelerate the ageing of a paint system, i.e. toweaken the corrosion-protective properties faster than through naturalexposure / weathering.

ASTM Abbreviation for American Society for Testing and Materials, issuingstandards for testing of paints (among others).

Atmosphere A mixture of gases, and normally also aerosols and particles, that

surrounds a given object.

Atmosphericcorrosion

Corrosion with the Earths atmosphere at ambient temperature as thecorrosive environment.

Back-burning Steel is an excellent conductor of heat. When hot work (welding, flame-cutting, fairing, etc.) is carried out on one side of steel, any paint appliedon the reverse side is likely to be damaged by the heat transferred throughthe steel. This is called back-burning and may affect any type of paint(shopprimer, primer, mid-coat, etc.). If the paint becomes charred, it iseasy to detect, but weaknesses in the paint system may develop beforevisual charring takes place.

Barrier coat A coating used to isolate a paint system from the surface to which it isapplied. Also called Sealer Coat.

Binder The binder is the component of paint that after drying forms a continuousfilm adhering to the substrate. The pigment particles are distributed moreor less uniformly in this layer. The choice of binder is crucial for the

properties of the paint, and determines to a large extent properties such asadhesion, hardness, elasticity, gloss and resistance to weathering, water,chemicals etc. Binders are based on synthetic resins or natural compoundsand rosins, or combinations of such. See also Generic type.

Biocide General name for any substance that kills or inhibits the growth of micro-

organisms such as bacteria, moulds, slimes, fungi, etc. Some of them aretoxic to humans. Biocides are used in antifoulings (prevent marinegrowth), in decorative paints for external use (fungicide), and as in-can

preservative for water-borne paints.

Bituminouscoating

Asphalt or tar compound used to provide a protective coating.

Blastcleaning Cleaning and roughening of a surface (particularly steel) by the use ofmetallic or non-metallic grit or metal shot (usually steel), which is

projected at high speed against a surface by compressed air, centrifugalforce, or water. Will remove corrosion, paint, coatings and contaminants,

but not salts, grease and oil.


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Bleeding The diffusion of colorants through a coating from a previously paintedsubstrate. Tar, bitumen, soluble pigments and dyestuff are typicalcolorants that may cause bleeding. Solvents from the latest applied coatare often the vehicle for the undesired migration of such colorants.

Blistering Formation of dome-shaped projections in paints or varnish films resultingfrom local loss of adhesion and lifting of the film from an underlying

paint film (inter-coat blistering) or the base substrate. Requires a drivingforce to be inflated, be it hydraulic pressure (liquid filled blisters, seeOsmotic blistering) or pneumatic pressure (air or vapour-filled blisters,see Dry blisters, Solvent entrapment, air entrapment andPopping).

Blooming Epoxy coatings, especially amine cured, are particularly subject to poorcuring at cold, humid weather conditions. The amines react with carbon

dioxide (CO 2) and humidity (H 2O) in the air to form an AmineCarbamate, commonly referred to as amine blooming or aminesweating. The result is a tacky film, often appearing as white stains.These are water-soluble and can be removed by using clean, warm waterand rags. To avoid lack of adhesion between coats it must be removed

before over-coating.

Blushing (alsocalledwhitening)

Until paints have cured properly there is a risk of having blushing. It is afilm defect that appears as a milky opalescence and loss of gloss as thefilm dries. Condensation and moisture on the surface of the coating beforethe paint has dried / cured completely form white spots on the surface.When formed, blushing will remain on the surface, even after the coating

has dried.BSI Abbreviation for British Standard Institution, the governing body in

Great Britain for BS-standards.

Calcareousdeposit

Deposits containing calcium or calcium compounds.

Catalyst A substance of which a small proportion notably affects the rate of achemical reaction without itself being consumed or undergoing achemical change. An example is peroxide, which starts up the chemicalcuring process of polyester coatings.

Cathode The negative electrode of an electrolytic cell, to which positively chargedions migrate when an electric current pass through the cell. In a primarycell (battery), the anode is the positive electrode. See also Anode andSacrificial Anode.

Cathodic area The negatively charged area (metal surface) in corrosion cells wherereduction (e.g. of oxygen) takes place. This part of a metal surface doesnot corrode.

Cathodicprotection(CP)

Method of reducing the rate of corrosion of a metal by making it cathodic,i.e. more negative. This can be done by applying current from an external

power source (impressed current) or by letting another, more negativelycharged metal corrode (sacrifice). In zinc-rich paints and sacrificialanodes the active zinc (or aluminium) will protect the less active metal -


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steel. The steel will have cathodic protection.

Chalking That phenomenon manifested on cured coatings (paints) by the presenceof loose, removable powder, evolved from the film itself, at or just

beneath the surface, generally caused by ultraviolet exposure andsubsequent degradation of the binder. Must be removed before new paintis applied.

Checking A defect in a coating (paint) film that manifests itself by slight breaks inthe surface of the film. If the underlaying surface is visible, it should beclassified as Cracking.

Chemicallycuring paints

Paint consists of a base component and a curing agent component. The paint film cures by evaporation of solvents, if present, and subsequentchemical reaction between the base and the curing agent component.Examples are epoxy and polyurethane paints.

Chlorinatedrubber

Resin formed by the reaction of rubber with chlorine. Often used as binder for some physically drying paints.

Cissing A defect in which wet paint or varnish film recedes from areas of thesurface, leaving either no coating or an attenuated one. Usually caused bysurface contaminants such as oil, grease, silicone, etc.

Climate The prevailing weather conditions at a given location or in a given area.

Cleaner Chemical used for preparing / cleaning a substrate before paintapplication. May be based on detergent, degreaser, alkali, acid or other

cleaning materials, usually water or steam borne. Solvents / thinners may be used for cleaning paint equipment.

Close-upsurvey

Inspection of area that can be reached with the hand.

Coalescence The formation of a film of resinous or polymeric material when waterevaporates from an emulsion or latex system, permitting contact andfusion of adjacent latex particles. Action of the joining of particles into afilm as the volatile evaporates.

Coal Tar Black, viscous liquid (or semisolid) obtained by destructive distillation of bituminous coal as in coke ovens. The crude or refined product orfractions thereof are used for waterproofing, paints, roads, roofing,insulation, etc. Coal Tar Pitch is used as binder in paints, either alone orin combination with other binders (e.g. Coal Tar Epoxy).

Coat A continuous layer of metal material or a continuous film of paint orvarnish resulting from a single application (one layer) to form an evenlydistributed film when dry.

Coating A liquid, liquifiable or mastic composition that is converted to a solid protective, decorative or functional adherent film after application.

Cohesion The forces, which bind the particles of a paint or varnish film togetherinto a coherent whole. It is distinct from adhesion, which are the forcesthat bind the film to its substrate.


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Cold flow A paint film changing its appearance (shape) after it has dried completely,caused by external forces (pressure). May for instance on occations beobserved on the submerged part of a ship, where an initially smoothcoating surface has become rippled or adopted a wave-patterned profile,due to forces created by friction with the seawater.

Cold curing The process of curing at normal atmospheric temperature (as opposed toelevated temperatures).

Colourretention

Ability to retain original colour.

Compatibility 1. Of the products in a paint system: The ability of two or more productsto be used in a paint system without causing undesirable effects.

2. Of the products with the substrate: The ability of a product to be

applied to a substrate without causing undesirable effects.Conductivecoating

Accomplished by the addition of pigment that will conduct (static)electricity, such as graphite.

Confinedspace

An area which may be hazardous because a limited number of openingscould make escape difficult in an emergency, and because ventilation may

be inadequate to support life. The space may also present unknownhazards such as toxic or caustic chemicals, or flammable or explosivevapours.

Contaminants Foreign substances inadvertently added to a coating or found on asubstrate, that adversely affects the application, adhesion, curing and/orsubsequent performance of the applied coating.

Conventionalpaint

A collective description for single pack paints based on binders such as bitumen, alkyds and oils.

Copolymer Large molecule obtained by simultaneous polymerisation of differentmonomers.

Correction ofDFT

Application of one or more extra coats on top of an insufficiently thickcoating in order to obtain the specified DFT (see DFT).

Corrosion The deterioration of metal or of concrete by chemical or electrochemicalreaction resulting from exposure to weathering, moisture, chemicals, or

other agents in the environment is which it is placed.Corrosiondamage

Corrosion effect that is considered detrimental to the functioning of theaffected material (metal or concrete), the environment or the technicalsystem of which these form a part.

Corrosivity NOTE: DUBIOUS EXPLANATION, DO WE NEED THIS????

Ability of an environment to cause corrosion in a given corrosion system.

Coverage Ambiguous term that is used in some instances to refer to hiding powerand on other terms to mean spreading rate. The more precise terms are

preferred. See Spreading Rate and Hiding Power.

Cracking A break or split in a coating penetrating at least one coat, extending from


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the surface to an underlying coat or to the substrate. May be expected toresult ultimately in complete failure.

Cratering Formation of small bowl-shaped depressions in a paint film. Often caused by contamination such as silicone.

Crevicecorrosion

Corrosion that occurs within or adjacent to a crevice formed by contactwith another piece of the same or another metal or with a non-metallicmaterial. When this occurs, the intensity of attack is usually more severethan on surrounding areas on the same surface. Can be observed forinstance in stainless steel.

Crosslinking Applied to polymer molecules, the formation of chemical links betweenthe molecular chains to form a three-dimensional polymer during thecuring process. Found in two-pack paints and coatings.

Crossspraying Making two passes with a spray gun over the same surface at right anglesto each other. Technique used to build up high film thickness and evenfilm thickness without sagging.

Curing Agent Additive that promotes the curing of a coating film. A component of amulti-component coating that causes cross-linking and film-formation(curing).

Currentdensity

The electric current that flows from or to a unit area of a metal surface.Current density is given in mA/m 2 or A/m 2.

Curtains See Sagging

Daily log A form to be filled in each day during painting work which contain dataon temperatures, relative humidity, wet and dry film thickness, type of

paint, etc.

Degrease To remove grease and oily substances from a surface by usingemulsifying chemicals or detergents. Solvents may also be used, but

precautions must be taken to eliminate hazards to health and safety.

Delamination Failure of a coat of paint to adhere to the previous coat, leading toseparation of layers.

Descaling Removal of mill scale or caked rust (flake rust) from steel by chemical ormechanical means. See also Electrolytic Descaling.

Dew point The temperature at which moisture in the air will condense and form dewon available surfaces (unless the surface has a temperature above the dew

point, usual requirement is 3 oC higher).

Diluent A volatile liquid, single or blended, which, while not a true solvent for the binder in a paint or varnish, may be used in conjunction with the truesolvent without causing dissolution. A diluent is usually mixed with the

binder solution (vehicle) to achieve an effect, e.g. regulation of theevaporation pattern, adjustment of the paint viscosity or a reduction in thecost of the volatile part of the paint.

Dilute To dilute paints or coatings by means of thinners, in order to obtain better

application properties, or to improve wetting and penetrating properties


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on corroded or porous surfaces, and thus improve adhesion.

Dispersion Process of dispersing a dry powder (or pigment) on a liquid media in sucha way that the individual particles of the powder become separated fromone another and are reasonably evenly distributed throughout the entireliquid medium.

Documentation

The assembling and dissemination of written information or records insubstantiation of work done or facts quoted.

Drier Chemical that promotes drying or oxidation of air-drying paints.

Dry blisters Blisters in a paint film applied over a porous substrate (e.g. wood ormasonry materials). Caused by air in the pores expanding duringtemperature increases (e.g. heated up by strong sunlight), whereby theresulting pneumatic pressure inflates blisters in the paint film. Solvent

entrapment and air entrapment in paint films may give a similar result.These blisters will always be filled by air or by (solvent) vapours. Theywill be easier to detect in soft or flexible paints, while in thick andrelatively hard / inflexible films they may hardly inflate, merely looseadhesion in the affected areas.

Dry FilmThickness(DFT )

The thickness of a coating remaining on the substrate when the coatinghas hardened. DFT is usually measured with a magnetic orelectromagnetic gauge. Readings are in micrometer (0.001 mm) or mils(25.4 micrometer).

Dry-to-handle Time interval between application and ability to handle without excessivedamage.

Dry-to-recoat Time interval between application of the coating and its ability to receivethe next coat satisfactorily.

Dry spray Overspray or bounce back, creating a sand-like finish due to spray particles being partially dried before reaching the surface.

Dry-to-touch Time between application and tack-free condition.

Durability Degree to which paints and paint materials withstand the destructiveeffect of the conditions to which they are subjected. Often seen inconjunction with he expected life of a protective paint system to the firstmajor maintenance painting.

Dust Loose particulate matter suspended in the air or present on a surface prepared for painting, arising from blast-cleaning or other surface preparation processes, or resulting from the action of the environment.The size is normally 1- 100 m in diameter.

Efflorescence The powdery substance or crystals formed as a result of chemical changeor evaporation. Typical examples being water soluble salt deposited onthe exterior of cement or lime containing material (bricks, concrete, etc.).May accumulate under a paint film on a painted cementicious substrateand cause loss of adhesion.

Elastomer Polymer having rubber-like properties.


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Electrode Metal or other electrically conductive material that can function as ananode or cathodic in an electrochemical cell.

Electrodepotential The potential of a metal (electrode) in an electrolyte (e.g. seawater). The potential is measured against a reference electrode and is given in Volt ormV.

Electrolyte Electrically conductive liquid, e.g. seawater.

Electrolyticdescaling

Sacrificial anodes in the form of magnesium alloy strips are distributedevenly and welded or clamped to the internal surface of a tank, which issubsequently filled with seawater. An electrolytic reaction takes placewhich causes breakdown of the oxide (i.e. scale and rust) and a softcalcareous layer forms on the surface of the steel which forces the rustscale and poorly adhering paint film to loosen and fall off. Recommendedfor heavily corroded and un-coated tanks, or where corrosion has caused

breakdown of the paint in 70% or more of the area.

Electrostaticspray

A special electrostatic spray gun will give an electric charge to the paintdroplets as they leave the gun. The object to be painted is connected toearth, causing an electrostatic attraction of the charged paint droplets.

Emulsionpaint

Paint in which the binder is dispersed in water (emulsified) e.g. polyvinylacetate (PVA), polyvinyl acrylates (PVAc) etc.

Enamel Commonly used expression for any hard, glossy coating.

EPA Abbreviation for Environmental Protection Agency.

Epoxy A binder with a special chemical composition. Paints containing epoxyare usually of the two-component type, i.e. the addition of a curing agentis necessary to start the chemical reaction forming a hard film. Curing istemperature dependent. Epoxy paints are well known for their resistanceagainst chemicals and mechanical wear. Use of different epoxy types andcuring systems allow paint formulations to be developed for various

purposes.

Epoxyester Epoxy modified oil; single package epoxy, air-drying.

Epoxy coaltar

Coating containing a binder combination of epoxy and coal tar products,which give an especially waterproof film. A curing agent must be added,otherwise it will not cure.

Epoxy Mastic See Mastic

Erosion Phenomenon manifested in paint films by the wearing away of the finishto expose the substrate or undercoat. Erosion occurs as the result ofadvanced chalking or by the abrasive action of wind-borne particles ofgrit.

Ester Reaction product of alcohol and acid.

Etching Surface treatment using an acid. May be used on ferrous substrates (seePickling) or on concrete. Acid treatment of concrete is usually carriedout with hydrochloric acid (HCl). The most common purpose is to etch

powerfloated (see this) concrete floors to secure a good adhesion for floor


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paints.

Etchprimer See Washprimer.

Extender Mostly natural, but also synthetic minerals. Their main function is toreinforce the paint film. Application and anticorrosive properties of the

paint are influenced, as well as appearance (gloss), rheology (flow),durability, cost, etc.

Fading Reduction of brightness of colour (lightening / fading).

Feathered A gradual taper in thickness from a coated surface to an un-coated surface(creating a smooth transition between old paint and area to be repaired).

Filler Pigmented composition used for filling fine cracks and indentations toobtain a smooth, even surface preceding painting. Sometimes also used asa synonym for extender.

Film Film is a firm continuous layer, which is formed during the drying of the paint. See also Coat.

Filmthickness

The protective qualities of the paint or paint system depend upon thethickness achieved during application. Specialised equipment is availableto measure the film thickness. Wet film thickness (WFT) is including itssolvents immediately after application. Dry film thickness (DFT) is themeasurement after solvents have completely evaporated and the film hascured.

Final cure Time required for a coating (paint) to achieve the degree of curenecessary to permit commencement of intended service. Also termedfully cured.

Fineness ofgrind

A measure for size of dispersed particles in liquid paint; degree ofdispersion of pigments in the binder.

Fingering Expression used for broken spray pattern: fingerlike. May be caused by poor atomisation (pressure, viscosity, etc.), or wrong, defect or partly blocked / clogged spray tip.

Fish eyes Paint defect that manifests itself by the crawling of wet paint into arecognised pattern resembling small dimples or fish eyes. Typicallycaused by contamination.

Flaking The detachment of pieces of the paint film either from its substrate orfrom paint previously applied. It is the result of loss of adhesion, oftendue to stress/strain-factors or for instance corrosion taking place under thefilm.

Flame spray Any process whereby a material is brought to its melting point andsprayed onto a surface to produce a coating. The process includesmetallising thermospray and plasma flame.

Flashpoint The lowest temperature of a liquid at which it gives off sufficient vapourto form an ignitable mixture with the air near the surface of the liquid orwithin the vessel used. The term characterises the flammability of paints

and solvents. It is measured under standardised conditions and determinedas the temperature at which the vapour will be ignited (flash) by a spark


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or open flame.

Flash rusting Slight rust formation on a prepared steel surface soon after blast cleaningor water jetting.

Flocculation Formation of clusters of pigment particles in a fluid medium, which mayoccur after dispersion has been effected. The condition is usuallyreversible and the particle clusters can be broken up by the application ofmechanical forces. Flocculation may result in more rapid settling (usuallysoft), loss of colour strength and poor dispersion.

Floating /flooding

Separation of colour pigments in the wet film. Causes a deviation fromthe intended (original) colour.

Flow The degree to which a wet paint film can flow out after application so asto eliminate brush marks and produce a uniform smooth surface on

drying.Fluorescent Special pigments instantly transforming invisible radiation (UV light) to

visible light. Included for instance in high visibility coatings, used formarking hazardous areas or objects. See also Luminescence andPhosphorescence

Forced cure Acceleration of curing by increasing the temperature above ambienttemperature accompanied by forced air circulation.

Fouling Marine organisms growing on structures in water. See also Antifouling.

Full coat Application of a continuous coat in the specified film thickness, asopposed to touch-up and stripe coats.

Fungicide Biocide retarding or preventing growth of fungi. See also Biocide.

Galvaniccorrosion

Corrosion of dissimilar metals in electrical contact, e.g. steel andaluminium or mild steel and stainless steel.

Galvanisedsteel

Steel covered by a coat of zinc, applied by a variety of methods, e.g. byelectro-plating or by dipping in a molten bath of zinc (hot dip).

Gelling A process whereby paint or varnish thickens to jelly-like consistency. Cansometimes be seen when paint is stored under wrong conditions or hasexceeded its shelf life.

Generic type Generally: a group of coatings with the same type of binder. Sometimes(incorrectly) also used for coatings with the same type of active pigmentor functionality, e.g. zinc-rich, antifouling, heat resistant.

Glossretention

Ability to retain original sheen.

Grinding Use of power tools to remove adherent weld-spatters, rust, millscale, andfor rounding sharp edges, smoothen rough welding seams and correctfaults in the steel (delamination, etc.).

Grit Abrasive obtained from steel or slag that are predominantly angular, thathave fractured faces and sharp edges, and that are less than half-round inshape.


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Hardener See Curing Agent.

Heat

ResistantPaint

Paints that can tolerate exposure to higher temperatures than normal

paints. Most commonly based on inorganic binders, like silicone resin andsilicate. The upper temperature limit for zinc-rich versions is determined by the melting point of zinc (max. 400 oC), while aluminium pigmented products can accept higher temperatures (max. 600 oC).

Hiding power The ability of a paint to hide or obscure a surface over which it has beenapplied uniformly.

High buildpaint

Coatings that are applied in thickness greater than those normallyassociated with paint films and thinner than those normally applied with atrowel. (ISO 12944: min. 80 micr. DFT / SSPC: min. 5 mils / 125 micr.DFT).

High-solidpaint

A term used to describe paint materials with a greater than normal volumeof solids. Some states at least 70% solids, while others define it as morethan 85% solids.

Holdingprimer

A quick drying primer that is applied shortly after surface preparation has been carried out. It will preserve the pre-treatment (hold the blast) untilthe entire coating system is applied. It will thus form part of the completecoating system on the structure.

Holidays Application defect whereby small areas are left uncoated. When using aHoliday Detector, this means a discontinuity in a coating, whichexhibits electrical conductivity when exposed to a specific voltage.

HPWC High Pressure Water Cleaning is performed at pressures from 340 to 680 bar (5,000 to 10,000 psi.).

HPWJ High Pressure Water Jetting is a method of surface preparation whichrelies totally on the energy of a jet of water, at high pressure (from 680 to1,700 bar / 10,000 to 25,000 psi), to achieve the required cleaning of thesurface. See also UHPWJ.

Hydrolysis Disruptive reaction consisting of splitting a compound into two parts, oneof which combines with the H + ion of water and the other combines withthe OH - ion of water. Selfpolishing antifoulings take advantage of thisreaction.

Hydrophilic Having an affinity for water, capable of uniting with or dissolving inwater. The opposite of hydrophobic.

ImpactResistance

Ability of a coating to resist a sudden blow; ability to resist deformationfrom impact.

Inductiontime

Time between mixing a two component paint and starting its application.Recommended for certain paints for the curing process to start up in thetin before application commences, but the pot life must be strictlyobserved.

Industrial

atmosphere

The atmosphere contaminated by corrosive pollutants from local andregional industry (mainly sulphur dioxide).


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Inhibitor General term for compounds or materials (additives) that slow down orstop a chemical change, such as corrosion, oxidation, polymerisation,drying, skinning, etc.

Inorganic Containing no carbon.

Intermediatecoat

Coat(s) between priming and top coat(s). Sometimes also calledundercoat(s).

Intumescence The foaming and swelling of a coating when exposed to high surfacetemperatures or flames.

ISO Abbreviation for the International Organisation for Standardisation, aworldwide federation of national standards bodies.

Ketones Organic solvents containing CO grouping; commonly used ketones are

Acetone (diethyl ketone), MEK (methyl ethyl ketone), and MIBK (methylisobutyl ketone).

Laitance A milky white deposit on new concrete. May lead to reduced adhesion if paints are applied on top of such.

Latex A white, tacky aqueous suspension of a hydrocarbon polymer. The naturalversion of latex is the sap from rubber trees, but in paints the syntheticversions are used. These consist of synthetic resins emulsified in waterand used as binders in emulsion paints.

Leaching To remove or be removed from a substance by a percolating liquid.Example: cuprous-oxide pigment in antifouling paint being extracted

from the dry film by seawater.Life CycleAssessment(LCA)

A method for evaluating the environmental consequences at each stage ofa coatings life cycle, from raw material extraction throughmanufacturing, lifetime use and waste disposal.

Life CycleCost (LCC)

LCC-evaluation is a tool for comparing alternative protective systemsagainst each other in order to find the most economical solution for thelife span of the structure to be protected. It takes into consideration costsincurred during the construction and installation phase, and maintenancecosts over the planned service life of the structure. All relevant costelements should be included, such as costs for labour, materials,equipment, access, mobilisation, inspection, etc., all converted to net

present value.

Leafing Orientation of pigment flakes to the surface. The floating and slightoverlapping of certain metallic and other pigment particles in the form oflaminar flakes on the surface of a coating. Leafing occurs when such

pigments are mixed with a suitable vehicle and applied as a coating.

Levelling The measure of the ability of a coating to flow out after application so asto obliterate any surface irregularities such as brush marks, orange peel,

peaks, or craters which have been produced by the mechanical process ofapplication.

LifetimeThe useful service life of a structure, normally given in number of yearsfrom construction to scrapping.


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Lifting Softening and raising or wrinkling of a previous coat when applying anadditional coat, most commonly caused by the solvents in the last coat.

Lining A thick protective layer. Term often used in connection with internal protection of tanks, i.e. tank lining. A tank lining prevents corrosion of thetank itself, protects the content of the tank from being contaminated bythe tanks structural material, and makes cleaning of the tank easier. Themost common tank lining products are based on epoxy or polyester

binders, sometimes reinforced by glassfibre or glassflakes.

Localenvironment

The environmental conditions prevailing in the vicinity of a site /structure / workplace / component. Considerable differences may appearsurprisingly close to each other, e.g. under a ships bottom in a drydockcompared to on the dockside. See also Industrial / Marine / Rural / Urban

atmosphere.

LowerExplosiveLimit (LEL)

Low limit of flammability or explosibility of a gas or vapour at ordinaryambient temperature, expressed in percent of the gas vapour in air byvolume.

Luminescence The emission of visible or invisible radiation (e.g. light), unaccompanied by high temperature. Common examples are light from the firefly,fluorescent lamp tubes, television and computer screens. In general termsluminescence includes both fluorescence and phosphorescence (seethese).

Marineatmosphere

Atmosphere near the sea and close to the coastline in dependence ontopography and prevailing wind direction. Heavily polluted with sea-salt

aerosols (mainly chloride).Mastic paints Commonly referred to as epoxy mastics. They are high-solids, high-build

epoxy formulations with good surface wetting properties. They areformulated to wet and penetrate residual rust and give good corrosion

protection on surfaces prepared by hand tool or power tool cleaning.Often pigmented with aluminium flakes to retard moisture permeationthrough the film.

MaximumDry FilmThickness

(Max. DFT)

The highest acceptable dry film thickness, above which the performanceof the paint or the paint system may be impaired, often given inmicrometer (m) (0.001 mm).

MEK Methyl Ethyl Ketone, solvent used to test the proper curing of zincsilicate coatings (ASTM D 4752-87). See MEK-test

MinimumDry FilmThickness(Min. DFT)

The lowest acceptable dry film thickness, below which the performanceof the paint or the paint system may be impaired, often given inmicrometer (m) (0.001 mm).

MEK-test A test to check if a zinc silicate paint has cured properly. A white clothwetted with MEK (Methyl Ethyl Ketone) is rubbed back and forth 50times on a small area, which first has been cleaned properly with water.

The paint is fully cured if it is no zinc on the cloth after 50 double rubs.


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(See ASTM 4752)

Metalspraying

Application of spray coat of metal (usually zinc or aluminium) onto a prepared surface (usually shot blasted mild steel). The metal to be sprayedis rendered molten by passing it, in wire or powder form, through a flame

pistol that projects the semi-molten metal onto the surface by means of a jet of compressed air.

Micrometer(m)

Thickness of paint is usually measured in micrometre (m). Onemicrometre is one thousandth of a millimetre. Sometimes referred to onlyas Microns.

Mil One one-thousandth of an inch: 0.001. One mil is 25.4 micrometer

Mill scale The black oxide of iron produced during the hot rolling, hot fabrication,or heat treatment of steel.

Mist coat A very thin coat sprayed over the substrate to improve adhesion and/or fillup pores just before full coat to avoid popping and pinholes. See alsoPopping

Mixing ratio Ratio expressed by weight or volume of separately packaged componentsof a multiple-component coating by which the components are to becombined and mixed to uniform conditions before application.

MSDS Material Safety Data Sheet Printed information concerning a hazardousmaterial (chemical) which must be provided by manufacturers and madeavailable to all employees and customers.

Modifiedpaints

Paints containing more than one binder (e.g. Coal Tar Epoxy), or basedon a binder that have been chemically altered when compared to the mostcommon version of that particular generic type (e.g. Styrinated Alkyd).

Moisturecuring paints

The film dries initially by solvent evaporation. It cures chemically byreacting with moisture from the air. Too low relative humidity may

prevent a proper curing. Examples are ethyl silicate (1 and 2-pack) and 1- pack polyurethane.

Mordantsolution

An acid containing solution applied on steel and other metals for the same purpose as Washprimer, but does not leave a film.

Mud-cracking Irregular cracking that occurs as coating dries, appearing as a dried mud

puddle. Most commonly found in zinc silicate coatings that have beenover-applied.

NACE Abbreviation for National Association of Corrosion Engineers, anorganisation in USA.

Nominal DryFilmThickness(NDFT)

The dry film thickness specified for each coat or for the whole paintsystem to achieve the required durability.

Non-conformance

Expression used for products, procedures, work practises ordocumentation that do not meet acceptance criteria given in a

specification or a standard.


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Non-ferrous Term used to designate metals and alloys that do not contain iron or steel,e.g. brass, aluminium, zinc, copper, etc.

Non-volatilematter Ingredients of a coating composition that, after drying, are left behind onthe material to which they have been applied, and that constitute the dryfilm. Also called Solid content.

NORSOK Abbreviation for The competitive standing of the Norwegian offshoresector, the body governing NORSOK Standards,

Occupationalexposure limit(OEL)

Values for airborne hazardous / toxic materials that are to be used asguides in control of health hazards. They are given as time-weighedconcentrations to which operators / workers / others may be exposedwithout adverse effects. It may be given as maximum long term exposure(8 hours per day over extended periods) or short term exposure (max. 15minutes).

Occupationalairrequirement(OAR)

The amounts of air necessary to dilute vapours from one litre of paint to aconcentration below the administrative norm.

Opacity The degree to which a paint film is opaque (not transparent ortranslucent). See also Hiding Power.

Orange peel Dimpled appearance of dried film, resembling orange peel.

Osmosis Transfer of liquid through a semi-permeable membrane (e.g. a paint film),driven by a difference in solution concentration on each side of themembrane (osmotic pressure).

Osmoticblistering

Blistering caused by diffusion of water molecules through a paint filmcaused by a difference in soluble salt concentration. If for instance paint isapplied onto a substrate contaminated by salt and subsequentlysubmerged, an osmotic pressure will develop. This will force watermolecules through the paint film to dilute the salt under the film. Thewater will accumulate where the salt contamination is, creating a water-filled blister.

Overspray A deposit of wet or dry coating particles that has drifted onto a surfaceduring spray application. May often be caused by strong wind and/or too

long distance between spray nozzle and substrate.Paint A liquid product containing pigment(s), which, when applied to a

substrate, is converted to an opaque solid film having protective,decorative or specific technical properties.

Peeling Separation of one or more coats or layers of a coating system from itssubstrate due to loss of adhesion.

Peening To strike a surface (e.g. steel) with the peen of a hammer or a stream ofmetal shot. May remove material (old paint and rust) from the surface andcause indentations (roughness) in the surface. Recently introducedrotating peening tools may replace mechanical wirebrushing (prevent

polishing of the substrate and create a certain profile).


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pH Measure of acidity or alkalinity; pH7 is neutral; the pH value of acidsranges from 1 to 7, and of alkalies (bases) from 7 to and including 14.

Phosphating Metals are treated with phosphoric acid (immersion or spray) to form athin layer of metal-phosphate. This will have a corrosion-inhibitingfunction, commonly used in production lines for smaller components,metal-sheets too thin for blastcleaning, and car production.

Phosphorescence

Special pigments storing radiation (light) and emitting this as visual lightafter the radiation has ceased (lights up in the dark). See alsoFluorescence and Luminescence.

Physicallydrying paint

Solvent-borne: The binder is diluted by solvents. The film dries byevaporation of the solvents. The process is reversible, i.e. the dry filmremains soluble in its original solvents.

Water-borne: The binder is dispersed in water. The film hardens byevaporation of water and film-forming (coalescence) of the dispersed

binder. The process is not reversible, i.e. this type of coating is notredispersible in water after drying.

Pickling Treatment for the removal of rust and mill scale from steel by immersionin an acid solution containing an inhibitor. Thorough washing and drying

before painting should follow pickling.

Pigment A substance, generally in the form of fine particles, which is practicallyinsoluble in binders and solvents. Is used in paints because of its optical,

protective or decorative properties.

A pigment gives paint its colour, hiding power and often also protective properties.

Some pigments have a special function, e.g. cuprous oxide for anti-fouling paints and zinc phosphate for corrosion protection. Paints

pigmented with aluminium flakes and other laminar pigments, likemicaceous iron oxide and glass flakes, have a very low water and watervapours permeability. Pigments are often combined with extenders.

Pigmentvolumeconcentration

(PVC)

Ratio of the volume of pigment to the volume of total non-volatilematerial (i.e. pigment and binder) in a coating. The figure usually isexpressed as a percentage.

Pinholes Film defect characterised by small pore-like flaws in a coating whichextend entirely through the applied film and have the general appearanceof pinpricks when viewed by reflecting light.

Pitting Highly localised corrosion, usually in the form of cavities, holes or pits ofvarying depth in the surface of a metal.

Plasticiser A substance added to paint or varnish to impart flexibility.

Polyestercoating

Coating in which the binder is unsaturated polyester. It needs peroxidefor cross-linking. Most polyester coatings use glassflakes forreinforcement.


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Polyesterresin

Synthetic resin which is polycondensation product of dicarboxylic acidswith dihydroxy alcohols. Chemically curing.

Polymer A high molecular weight material created from lower molecular weightconstituents by chemical reaction.

Polyurethane A specially polymerised binder that is used in both one-component andtwo-component paints. Paints based on polyurethane are extremelyhardwearing and generally resistant to chemicals. Aliphatic types havegood gloss, colour stability and weather resistance.

Popping Eruptions in a film of paint or varnish after it has become partially set, sothat bubbles or craters remain in the film. May be observed when paintinga very porous substrate (e.g. zinc silicate).

Post-cure Heat (or radiation) treatment, to which a cured coating is subjected to

enhance the level of one or more properties.

Potable water Water fit for human consumption drinking water.

Pot life The maximum time during which a coating material supplied as separatecomponents should be used after the components have been mixedtogether. At the end of the pot life, curing will be so far advanced that the

paint will no longer possess the necessary properties for a satisfactoryresult. Paint must never be allowed to remain in spray equipment after theexpiry of its potlife.

Powdercoating

A 100% solids coating applied as a dry powder (electrostatically) andsubsequently formed into a film with heat.

Power toolcleaning

Use of pneumatic and electric portable power tools to prepare a substratefor coating.

PowerfloatingTreatment of freshly poured concrete floors to achieve a smooth and hardfinish. May involve special surface hardeners and sprinkling of drycement powder on the still wet concrete surface before smoothening withsteel-trowels (i.e. powerfloating, smaller areas may be done by hand). Theresulting finish is hard, smooth and result in less dust than regularconcrete floors. If paint is to be applied on a powerfloated floor,

pretreatment involving grinding (floor grinder), blast cleaning (track- blast) or etching (hydrochloric acid treatment, require safety precautions)

should be carried out to ensure a satisfactory adhesion.Prefabrication primer

See Shopprimer

Primer The first coat(s) of a paint system, obtained by application of a primer.

Priming coats provide good adhesion to sufficiently roughened cleanedmetal and/or cleaned old coating, ensuring a sound base for and offeringadhesion to the subsequent coats. They normally also provide corrosion

protection during the overcoating interval and the whole service life of the paint system.

Profile Surface roughness resulting from surface preparations, such as abrasive blasting, power tooling, chemical etching, or other means. Blast cleaning


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will create a roughness usually referred to as anchor pattern.

Profile depth The average distance between top of peaks and bottom of valleys in a profile. See Anchor pattern

Protectivecoating

An adherent polymeric film applied to a substrate for protection againstthe environment and for aesthetic effect.

Protectivecoatingsystem

The combined coats of metal materials and/or paint or related productsthat are applied to a substrate to provide corrosion protection.

Pump ratio The ratio between the area of the air motor piston and the area of the paint piston. A pump having a ratio of 40:1, operating with an air pressure of5kg/cm 2, will supply paint at a pressure of 200 kg/cm 2 as it leaves theairless spray pump (a drop in pressure will occur in the painting lines /

spray hoses).PVA paint Emulsion paint in which the binder consists of polyvinyl acetate latex.

PVB Poly Vinyl Butyral a physically drying binder used in certainshopprimers.

Qualityassurance

Administrative and engineering procedures employed to assure thedesired level of quality. The verification of the conformance of materialsand methods of application to the governing specification, in order toachieve a desired result.

Qualitycontrol

The system whereby a manufacturer (or contractor) ensures that materials,methods, workmanship, and the final product meet the requirements of agiven standard.

RAL Colour definitions issued by RAL, Deutsches Institut fr Gtesicherungand Kennzeichnung e. V.

Recoat time Interval required between application of successive coats.

Relativehumidity

The amount of water absorbed in the air as a percentage of the maximumamount the air can absorb at a given temperature.

Resin A material used as a binder constituent, which forms a non-crystallinefilm when dried.

Resistivity A measure of the specific electrical resistance of a material. Given inohm-centimetres ( cm).

Retarder See Inhibitor.

Rosin Natural resin obtained from pine after removal of volatile fractions.

Ruralatmosphere

The atmosphere prevailing in rural areas and small towns, withoutsignificant contamination by corrosive agents such as sulphur dioxideand/or chlorides.

Rust Visible corrosion products consisting, in the case of ferrous metals,mainly of hydrated iron oxides.

Rust Products applied to corroded steel, containing chemicals that will react


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converters with ironoxide (rust), and convert these to a more stable iron-compound.Great care must be taken when overcoating the converted steel, to makesure there are no un-reacted chemicals left from the converter. The better

alternative is to remove as much rust as possible and use a surface tolerantcoating. Rust converters are not recommended for submerged areas due tothe risk for osmotic blistering.

Rust gradesA, B, C, D

Steel surface rust grades/qualities according to ISO 8501-1.

Rustpenetration

First observed as tiny spots of rust appearing on a paint film. Given time,the spots may develop and form larger areas of corrosion. May be caused

by low film thickness, pinholes, other weaknesses / defects in the film, ormetallic contaminants incorporated in the film (e.g. from grinding or blastcleaning in the vicinity).

Rust stain Discolouration of (intact) paint film by water containing corrosion products (rust water). May typically be found on vertical areas, where arelatively small corrosion spot may cause rust staining to a considerablylarger area situated below the corrosion spot.

Sacrificialanode

A metal (e.g. aluminium or zinc) that is less noble than the metal it isintended to protect. The anode sacrifices itself when connected to anobler metal, such as iron. This provides the iron with cathodic

protection.

Sacrificial zinc or aluminium alloy anodes are welded, bolted or clampedto steel and submerged in an electrolyte, such as seawater, to provide

cathodic protection. Anodes must be fixed so that they are in electricalcontact with the steel they are to protect and must not be greased or painted.

Sagging The downward movement of a paint film between the times of applicationand setting, resulting in an uneven coating having a thick lower edge.

Saponify The alkaline hydrolysis of fats whereby a soap is formed. Oil or alkyd based paints and varnishes will saponify (decompose) in an alkalineenvironment in the presence of moisture, e.g. new concrete, fresh plasteror in contact with zinc (zinc rich primers and galvanised steel).

Scattered

damage

A large number of damages to a coating, scattered over a wide area, e.g.

rust penetrations and blisters.Sealer coat A relatively thin coat of a compatible type, forming a seal between the

existing surface (old paint or uncoated substrate) and a new coat to beapplied. The purpose of the sealer coat can be to prevent bleeding fromthe substrate, to fill (or seal) a porous substrate (e.g. concrete or leach-layer in old non-polishing antifouling coats), adhesion improver, or toform an acceptable transition between two otherwise incompatible paints.A sealer coat may be used by itself to reduce water absorption in bricksand concrete structures, and to reduce the problem of dusting and cleaningconcrete floors.

Semihardcoating

A coating that stays soft and flexible, but is hard enough to touch andwalk upon. Only certain coatings have such properties. They will give


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temporary protection of rusted steel surfaces.

Sensitisation A condition in which a chemical causes an allergic reaction to individualsafter repeated exposure. Once sensitisation has been developed, evenminimal exposure to the particular chemical can provoke substantialallergic reactions, preventing the individual from any work containing arisk of such exposure.

Settling The sinking of pigments, extenders or other solid matter in a paintstanding in a container, with a consequent accumulation on the bottom ofthe can.

Sharp edges Gas-cut steel edges and outside corners of steel structures. Such edgesmust be ground round by disk-grinding and stripe coated.

Shelf life The time during which a coating material will remain in good condition

when stored in its original sealed containers under normal storageconditions.

Shopprimer A quick-drying coating applied as a thin film (15-25 m) to metal surfaceafter cleaning (e.g. blast cleaning), to protect the steel during storage andsubsequent fabrication. Shall protect the surface from corrosion duringconstruction and until the final paint system is applied. All application ofshopprimer takes place in automatic shoppriming plants. Also called

prefabrication primer. There are many types of shopprimers available, andit is important to select the correct one for the intended service / exposure.

Shot Particle used for blast cleaning that is predominantly round, with a lengthof less than twice the maximum particle width, without edges, brokenfaces or other sharp surface defects.

Shotblasting Blast cleaning with an abrasive consisting of round steel or iron shot.Usually used in shopprimer plants (mixed with grit), propelled bycentrifugal wheels.

Silicate Water borne sodium, potassium or lithium silicate, and solvent borneethyl silicate are used as binders in zinc rich coatings. After curing theyform an inorganic film (zinc silicate), which is non-flammable and cantolerate high temperature.

Silicone resin Resin based on silicone instead of carbon. Often used in heat resistant paints.

Silol polymer A new type of binder used in antifouling paints. It does not contain anyorgano-tin, but replicates the hydrolysing properties of tin-copolymers,thus providing genuine tin-free selfpolishing antifoulings.

Siloxane A compound of similar structure to paraffin hydrocarbons, but wherecarbon is replaced by silicon. Used for some speciality coatings.

Skinning Film formed over a liquid coating during storage. Frequently experiencedin partially used tins containing airdrying paints.

Slurryblasting

Blast cleaning where water is injected in the air/abrasive stream to reducethe dust problem and subsequent pollution caused by air-borne particles.


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Soft coating Coating that remains soft, so that it wears off when touched; often basedon old or sheep wool grease (lanolin).

Solids byvolume The volume of the nonvolatile portion of a composition divided by thetotal volume, expressed as a percent. In other words, the film-forming partof the coating (dry film) given as percent of the total volume of the paint(wet film).

Solvent A single or blended volatile liquid, in which the binder is completelysoluble. The solvent evaporates from a paint or varnish film afterapplication.

Solvent borne Paints and coatings containing organic solvents as thinner (to obtainsatisfactory application properties) are classified as solvent borne.Other classifications are solvent free and water borne.

Solvententrapment

Caused by a paint film drying too quickly on its surface, preventing allsolvent from leaving the film before it closes up. May occur during hotand windy conditions, or in confined space with insufficient ventilation.The resulting film will contain pockets of solvents, which eventually willescape and leave behind voids in the film, like in a Swiss cheese. Reducesthe paint films protective properties considerably and may lead to

blisters.

Sophisticatedpaints

Paints that are based on binders such as epoxies, acrylics, vinyls etc.Sophisticated paints generally give a higher level of protection thanconventional paints.

Spark test Method of detecting holidays on metallic substrates by means of aHoliday Detector. This means using a spark test tool for identifying adiscontinuity in a film, which exhibits electrical conductivity whenexposed to a specific voltage.

Sprayapplication

Method of application in which the coating material is broken up into finemist that is directed onto the surface to be coated. This atomisation

process may be created by high hydraulic pressurised paint beingsuddenly released into atmospheric pressure (airless spray), or by acompressed air jet (air spray / conventional spray) tearing the paint tosmall pieces.

Spray pattern The pattern formed on the substrate while applying paint by (airless)spray. Will be influenced by the proper atomisation of the paint whileleaving the spray gun, and by the technique applied by the spray operator(See for instance Cross spraying).

Spray tip During spray application, paint leaves the spray gun through an orifice(opening) in its exchangeable tip. The orifice is shaped such that the paintleaves the tip in a fan-shaped stream of droplets, with an elliptical crosssection. Each spray tip has a clearly defined orifice, defined by the size ofits opening and its angle (width of the fan). Each paint requires a specifictip size (orifice) to achieve the best application result. The tips angle willdepend both on the particular paint and on the object to be painted(narrow for smaller details, wide for larger clean areas). Recommendedtip-size can be found in individual paints technical data sheets.


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Spreadingrate

The number of square meter over which one litre of paint can be spread atthe specified film thickness. May also be expressed as square feet pergallon.

SSPC Abbreviation for Steel Structures Painting Council, an organisation inUSA that, among other activities, issues standards and recommended

procedures.

Steel surfaceprofile

See Anchor pattern.

Stripe coat A supplementary coat applied to ensure adequate protection of criticalareas like edges, welds, corners and areas with poor accessibility. Should

be applied prior to the main application of each coat in a paint system.

Substrate The surface to which the coating has been or is to be applied.

Surfacedefects

The existence in a coating of any of the following conditions whichimpair its performance for the intended surfaces: (a) fine line cracking;(b) checking; (c) alligatoring; (d) mud cracking; (e) blisters; (f) pinholes;(g) damages or abraded areas; or (h) anything that would be a defect inthe coating system.

Surfacepreparation

Any method or preparing a surface for coating.

Surfaceprofile

See Profile

Tackiness Paint film remains soft and tacky after normal drying time has beenexceeded. May be caused by a number of conditions, such as too highfilm thickness, excessive or wrong thinner, inadequate ventilation, wrongor lack of curing agent, low temperature or expired shelf life.

Tar epoxy See Epoxy coal tar

TBTO Abbreviation for tributyltin oxide, a biocide used in certain coatings.

TDS Technical Data Sheet. Information sheet issued by the paint manufacturer,containing technical information about a particular paint.

Thermoplasti

c

Softening under heat, regaining hardness on cooling.

Thinner A volatile liquid, single or blended, added to a product to lower theviscosity. Normally, thinners are either solvents or diluents or mixturesof both. They are also used to flush / clean application equipment.

Thixotropicpaint

Semi-solid or gel consistency when undisturbed, but flow readily whenstirred or shaken or when being applied (shear forces). The process isreversible. A fluid paint reverts to a gel consistency when the shear forcescease. When applied they flow easily when being worked but quicklyregain a gel consistency, which assists in preventing runs and sags.

Threshold

limit values

Values for airborne hazardous / toxic materials that are to be used as

guides in control of health hazards. They are given as time-weighedconcentrations to which operators / workers / others may be exposed


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(TLV) without adverse effects. It may be given as maximum long term exposure(8 hours per day over extended periods) or short term exposure (max. 15minutes).

Tie coat A coat designed to improve intercoat adhesion and/or avoid certaindefects as pinholes / popping during application. Often used when over-coating zinc silicate coatings.

Tin-copolymer

A resin used in self-polishing antifoulings, incorporating organotin (TBT)in the polymer. Hydrolyses in seawater, resulting in the polishing effect.

Top coat The last coat(s) of a paint system, designed to protect the underlying coatsfrom the environment, to contribute to the overall corrosion protectionoffered by the system and to provide the required colour.

Touch-up Application of paint on areas of previously painted surfaces to repair

mars, scratches, and small areas where the coating has deteriorated, inorder to restore the coating to an unbroken condition.

Transparency A film giving incomplete hiding of a surface, it has a lack of hiding powerand permit light to pass through.

Two-componentgun

Spray gun having two separate fluid lines leading to the spray gun, wherethe two components will be mixed and atomised.

Two-componentpaint

Paint that is chemically curing i.e. the product is supplied in twocomponents, base and curing agent (A component and B component).These two components must be mixed before the paint is applied.

UHPWJ Ultra High Pressure Water Jetting a method for cleaning substrates priorto painting. Delivers water at a pressure exceeding 25,000 psi (170 Mpa /1,700 bar), which can remove old paint, rust and other undesirable matterfrom a steel surface. Will not create any surface profile (roughness), butcan reveal existing profile from under old coatings. Cleanliness caninitially be compared to Sa 2 (blast cleaning), but may quickly besubjected to flash rusting.

Undercoat Same as intermediate coat.

Undercutting The gradual penetration and spread of corrosion beneath a coating from a break or pinhole in the film or from unprotected edges.

UpperExplosiveLimit (UEL)

Upper limit of flammability or explosiveness of a gas or vapour atordinary ambient temperatures, expressed in percent of the gas vapour inair by volume. (SSPC)

Urbanatmosphere

The contaminated atmosphere prevailing in densely populated areaswithout significant industry. It has moderate concentrations of pollutantssuch as sulphur dioxide and/or chlorides.

Vapours The gaseous phase of matter that normally exists in a liquid or solid state.

Varnish A product which, when applied to a substrate, forms a solid, transparentfilm which has protective, decorative or specific technical properties.

Varnish (a clear coating) is substantially the same as paint, the difference


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being that a varnish do not contain pigments.

Vehicle The liquid portion of paint, in which the pigments are dispersed. Avehicle is composed of binder(s) and thinner(s) (if any).

Vinyl resin Polymerised, often chlorinated, compositions used as binder in physicallydrying paints. Vinyl resins include polyvinyl acetate, polyvinyl chloride,copolymers of these, the acrylic and methacrylic resins, the polystyreneresins, etc.

Vinylestercoating

Coating in which the binder is vinylester resin. It needs peroxide forcross-linking. Most vinylester coatings need glassflakes forreinforcement.

Viscosity A measure of fluidity; the internal friction of a fluid that influences itsflow.

VLCC Very Large Crude Carrier, term used for large ships carrying oil (oiltankers)

VOC content The mass (weight) of volatile organic compounds present in a coatingmaterial, as determined under specific conditions. Often given as grams ofsolvents in one litre of paint.

Voids Empty spaces of molecular or larger dimensions occurring betweenclosely packed solid particles. Voids may occur in paint films due to dry-spraying, solvent retention (entrapment), air trapped within the film,foaming during application, etc.

Volatileorganiccompound(VOC)

Any organic liquid and/or solid that evaporates spontaneously at the prevailing temperature and pressure of the atmosphere with which it is incontact. See VOC content.

Volume ofsolids

See Solids by volume.

Washprimer Priming paint usually supplied as one- or two-component product. The paint contains carefully balanced proportions of an inhibiting chromate pigment, phosphoric acid, and a synthetic resin binder mixed in analcohol solvent. On clean, light alloy or ferrous surfaces, and on manynon-ferrous surfaces, such paints give excellent adhesion, partly due tochemical reaction with the substrate, and give a corrosion-inhibiting film,which is a good basis for the application of subsequent coats of paint.Although these materials are referred to as primers, the films that they

produce (when applied correctly) are so thin that it is more correct toconsider them as etching solutions and follow them with an ordinary

primer if maximum protection is required. Over-application can have verynegative effects on the total system (max. 10 micr. DFT). Jotun does notrecommend this product to be used in areas to be submerged, nor undertwo-pack paints (epoxy, polyurethane, polyester, etc.).

Water borne Paints and coatings containing water as the main thinner (to obtainsatisfactory application properties) are classified as water borne,

although most of them will also contain smaller amounts of organic


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solvents (co-solvents). Other classifications are solvent free andsolvent borne. Waterborne paints have greater humidity andtemperature limitations than solventborne types of paint.

Water jetting Cleaning / surface preparation using only a jet of water. Requiresdedicated equipment (pump, hoses, gun, and nozzle). Its efficiency isdetermined by the equipment, but most of all by the pressure of the water

jet. NACE has made following classifications:

Low Pressure Washing (LPW): Below 34MPa/340 bar/5000 psi)High Pressure Washing (HPWC): 34-70MPa/340-680bar/5000-10000psi)High Pressure Waterjetting (HPWJ): 70-170MPa/680-1700bar/10000-25000psi)Ultra-High Pressure WaterJetting (UHPWJ): Above 170MPa/1700bar/25000psi)

See also UHPWJ.

Weathering Behaviour of paint films when exposed to natural or artificially

accelerated weather conditions, characterised by changes in colour,texture, strength, chemical composition and other properties.

Weld slag Non-metallic deposits formed during welding.

Weld spatter Deposit on or adjacent to welding seams produced by weld metal duringelectric hand welding operation (drops of semi-molten metal). Suchspatter is unacceptable for over-coating due to their sharp protrusions, andmust therefor be removed prior to coating application.

Wet blasting Blast cleaning where the media carrying the abrasives is water instead ofcompressed air.

Wet FilmThickness(WFT)

Wet Film Thickness of a coat of paint, measured before its solventsevaporate. A wet film comb is used immediately after application in orderto check that the applied WFT is the one that corresponds to the specifiedDFT.

Wetting The ability of a vehicle to spread uniformly and rapidly over the surfaceof pigment particles. A vehicle with good wetting properties assists in thegrinding or dispersion of pigments and the ability to wet the surface towhich the finished coating is applied.

White rust White to dark grey corrosion products on zinc-coated surfaces.

Wire

brushing

Surface preparation of steel by hand cleaning tool comprised of bundles

of wires, or by mechanical (power) rotating wire brushing.Wrinkling A surface defect in a paint film resembling the skin of a prune.

Zinc fever An acute but short-lasting illness caused by the inhalation of zinc oxidefumes. The symptoms can include weakness, dryness of throat, chills,aching, fever and vomiting. Symptoms can last for about 24 hours and

patients will recover fully. Zinc fever is not known to be injurious tohealth. Zinc fever is most commonly experienced in connection withgalvanising work and when welding or flame-cutting primers containingzinc dust pigment.

Zinc

phosphate

A pigment with corrosion preventing properties.


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Zinc richpaint

Anti-corrosive primer for iron and steel incorporating zinc dust in aconcentration sufficient to give electrical conductivity in the dried film,thus enabling the zinc metal to corrode preferentially to the substrate, i.e.to give galvanic (cathodic) protection.

Zinc salt Zinc metal is not stable and will start to react with elements in theenvironment. Water and carbon dioxide will react with the zinc andcreate zinc salts. Also called White Rust due to its light colour. May befound on galvanised surfaces and zinc rich paints.

Zinc silicatepaint

Zinc filled paints based on an inorganic binder. Zinc silicates give veryhard films and are resistant to solvents and high temperature.

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