Powder Coating Glossary

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CONTENTSA …………………………………. 2 – 5B …………………………………. 6 – 7C …………………………………. 8 – 1214–D (13)16–E (15)19F (17)–G (20)H (21)23–I (22)K (24)L (25)27–M (26)N (28)–30 O (29)34–P (31)–36 R (35)39–S (37)41–T (40)U (42)V (43)W (44)Y (45)Z (46)Powder Coating GlossaryAABRASIVEA coarse material used in blast cleaning, such as sand, steel shot, glass beads or plastics.ABSORPTIONProcess of soaking up or assimilation of one substance by another.AC (CURRENT)Alternating electrical current.ACCELERATORMaterial that accelerates the curing or crosslinking, a mixture of crosslinkers or resins. Catalyst.ACICULAR PIGMENTSPigments which have needle shaped particles.ACRYLICA powder coating with a significant content of a polymer containing short chain esters of various acrylic monomers.ACRYLIC RESINA clear resin derived from polymerised esters of various acrylic monomers. Acrylics are used for automotive topcoats and other applications where resistance to chalking with exposure to sunlight is important.ADDITIVE CHEMICALSAdded to a powder coating to improve some properties, such as flow, gloss and texture control.ADHESIONDescribes bonding strength. It is the molecular attraction to the substrate surface to which a powder coating is applied. A condition where one material is attached to another by means of surface attraction. Adhesion is affected by the condition of the surface to be coated.ADSORPTIONProcess of attraction to a surface.AEROSOLDispersing of a liquid into a gas, for spraying, often used for touch-up paints. AGGLOMERATIONPowder particles bound loosely together into clusters containing trapped air.AIR CLASSIFICATIONDevice used in powder coating manufacture to aid in particle size management. AIR, COMPRESSEDAir at any pressure greater than atmospheric pressure.AIR HOSEA section of non-metallic tubing used to deliver compressed air for paint or powder application.AIR RECEIVERSTanks into which compressed air is stored from the air compressor. Receivers help eliminate pulsing in the discharge lines and also act as storage capacity during intervals when demand exceeds the capacity of the compressor.AIR VALVEControl valve in an air system for setting volume and pressure.AIR VELOCITYMeasurement of air speed, typically in feet or metres per minute.AIR VOLUMEMeasurement of air volume, in cubic feet or metres per minute.ALKALICaustic, inorganic substances that share the characteristic of being strongly basic (high pH) (examples are Sodium Hydroxide or Caustic Soda).AMBIENTSurrounding environmental conditions. For example ambient temperature. AMIDESOrganic compounds. A structure sometimes used in curing agents in Epoxy powder coatings.AMP (AMPERE)A unit of electrical current flow. The current produced by one volt applied across a resistance of one ohm.ANTI FOAM AGENTMaterial used in pre-treatment systems to reduce the tendency of the chemicals to foam.ANTI OXIDANTAn organic compound added to coatings to retard oxidation and deterioration. APPLICATIONProcess of applying a coating to a substrate.AQUEOUSA water based material.ARCINGA discharge of built up electrical charge, often forming a spark to a point of lower charge or earth.ASTMThe American Society for Testing Materials.ATTACHMENTRetaining foreign molecules on the surface of a substance.ATOMThe smallest unit of an element that still possesses the properties of that element. ATOMISAITONThe distribution of powder particles with air to form a fine pattern during the spraying application process.ATOMISING AIRAir injected into the powder path to atomise it into a pattern.BBACK IONISATIONA condition, which may occur during electrostatic application of powder coating where excessive build up of charged powder particles limits further powder to be deposited onto the substrate. A pockmarking pattern usually occurs on the powder surface.BELLElectrostatic spray device whose applicator is bell shaped. Centrifugal force throws the powder off its edge into a fine pattern. The charged particles are then attracted to the work surface.BINDERThe portion of the powder formulation that forms the primary strength of the film. It binds pigments and additives into a sold film and to the substrate.BITSContaminations in the surface of the coating seen as lumps.BLAST CLEANINGRemoval of surface contamination and corrosion products by use of air and mechanical abrasives (also referred to as sand or shot blasting).BLISTERING BUBBLESFormed under the cured powder film, usually caused by the expansion of trapped air, moisture or corrosion.BLOOMINGA hazy appearance on the surface of a coating.BRIDGINGThe ability of a finish to cover cracks, voids or small gaps without a break in the film. BTU BRITISH THERMAL UNITThe amount of heat required to raise the temperature of 1 pound of water by 1o F.BULK DENSITYMass per unit of volume in powder form, including the air trapped between the particles.CAKINGA compacted mass of powder.CALORIEUnit of heat. The amount of heat required to raise the temperature of 1 gram of water by 1o C.CARTRIDGE BOOTHSA type of powder recovery booth that incorporates a cartridge filter system to collect overspray powder.CATALYSTA special chemical that promotes or accelerates the curing reaction or reduces stoving temperature.CAVITATIONSFailure of a powder to flow into the intake of a feed system “rat holing”. CENTRIFUGALTo force in a direction away from the centre.CFMCubic Feet per Minute.CHALKINGSurface loss of colour and gloss in a coating from degradation of the binder (resin) by the UV components in sunlight. Can be seen as a white deposit on the cured coating surface.CHEMICAL CONVERSION COATINGA chemical treatment of the metal surface to convert it to another chemical form. It increases resistance to corrosion and promotes adhesion of the coating.CHEMICAL STRIPPERA strong solvent or blend of chemicals that will remove the cured film from the metal substrate.CHIPThe result of breaking extruded powder coating after cooling (also known as kibble). CHIPPINGThe breaking away of small portions of a paint film due to the inability of that film to flex under impact, thermal expansion or the contraction of the surface.CISSING CRATINGDisc shaped indents in the surface of the film, often caused by oil or silicone contamination.CLEANERDetergent, alkali, acid, solvent or any other material used to clean and degrease before the application of a coating.CLEARCOATAn un-pigmented coating. Can be a protective coating over a coloured or metallic basecoat or metal (example – brass).COLOUR-FASTNon fading. The ability to maintain colour under specified conditions. COMPATIBILITYThe capacity of powder coatings to be mixed and applied so as to show no visible, mechanical or any other detectable defect.COMPOSITIONFormula, make up, analysis. A specific combination of ingredients.COMPRESSORMachine design for compressing air or gas from an initial intake pressure to a higher discharge pressure.CONDENSATIONCooling of vapour to produce a liquid or a solid. E.g. steam cooling on a cold surface to produce water molecules.CONTAMINANTSForeign materials such as dirt, dust or oil that can be detected in the cured powder film, pre-treatment chemicals or air supply.CONTINUITYA surface free from any defects.CONTRAST RATIOA value related to the hiding power of a coating. The ratio of reflectance of the coating over black and white backgrounds at equal film thickness.CONVERSION COATING(see chemical conversion coating)CO-POLYMERLarge molecules resulting from the simultaneous polymerisation of two or more monomer units.CORONAAn area of ionised air formed by a discharge of electricity commonly used in powder electrostatic spray equipment.CORONA CHARGINGThe process of introducing a static electrical charge on powder particles by passing the powder through an electrical field generated by high voltage.CORROSIONDecomposition or reaction or metal with oxygen, water or other chemicals.CORRISION INHIBITOR PIGMENTSPigments that retard the corrosion process in the substrate.CRACKINGSplitting or disintegration of a powder film with breaks penetrating through to the substrate.CRAZINGFine, random cracks or fissures in a paint film, caused by shrinkage.CRATERINGSmall round depressions in a powder film.CREEP/CREEPAGECorrosion under a scribe line or an area of damaged coating or edge, after salt spray testing or other testing.CROSS CONTAMINATIONA condition when two or more powders are mixed by accident usually reducing quality.CROSS HATCHTest to determine adhesion. Lines are scribed through the coating film to the meal surface to form a grid of squares of defined size (1mm or 2mm).CROSS-LINKERA chemical catalyst that promotes the crosslinking of polymer molecules.CUREThe reaction between resin and hardener to form the final film properties.CURE AGENTHardener or crosslinkers. Additive that promotes the curing of a film.CURE OVENHeated chambers for the purpose of stoving the powder coating.CYCLONEA cylindrical device that separates powder of particles from air. The system works by centrifugal forces spinning the particles around its perimeter, the usable powder is collected at the bottom and the air with finer powder particles extracted from the top.DC (CURRENT)Direct electrical current.DECORATIVE COATINGA coating designed primarily for appearance and secondarily for protection. DEFLECTORConical shaped disc attached to the end of the powder gun to evenly distribute the powder in a 360o pattern.DE-IONISED WATERWater containing no ions other than hydrogen, oxygen and hydroxyl ions. Usually produced through the use of ion exchange resins and used for the final rinse in pre-treatment processes.DELAMINATIONSeparation between two layers of coatings or between coatings and substrate. DELIVERYThe process of moving the powder through the application equipment to the end product.DE-MINERALISED WATERSee de-ionised water.DETERGENTA surface active agent that is able to clean soiled surfaces.DEW POINTTemperature at which water condenses from air at atmospheric pressure. Dew point varies with relative humidity.DIFFUSERA porous material used in an air line to evenly distribute the air.DISPERSIONSuspension of one substance in another.DRY BLENDMaterial generally added into the final powder as a dry additive without any melting. DFTDry Film Thickness. Depth of applied coating after curing.DRY FLOWThe properties of a powder coating that relates to the ease of movement or transportation with air or vibration.DRY FLOW ADDITIVEAn additive that improves the transportation properties of the coating in the powder state. It improves the free flowing characteristics (for better fluidisation or transporting via feed lines) along with the sieving.EDGE COVERAGEThe ability to flow over, build and adhere to the sharp corners, angles and edges of components.ELASTICITYThe ability to recover from stretching.ELECTRODEA metal filament within or at the end of a powder spray gun used to create air ions at high voltage to produce charged particles (Corona)ELECTROSTATIC CHARGEThis is a charge that is carried on the surface of an insulated object such as a powder particle. The charge can be generated by friction or applied by an external field or corona.ELECTROSTATIC DEPOSITIONCharged powder particles adhering to an earthed substrate by virtue of their electrostatic charge alone.ELECTROSTATIC FLUID BEDA fluid bed equipped with an electrode grid to charge powder so that it is deposited on an earthed component.EPOXYA type of powder coating manufactured using epoxy resins, generally having high mechanical strength, chemical and corrosion resistance. But limited in gloss and colour retention when exposed to sunlight.EPOXY RESINFilm forming binder usually made from Biphenyl-A and Epicholrohydrin. Characterised as a Polyether.EROSIONWearing away of a coating to expose the substrate.ESTERA chemical formed by the reaction of an acid and an alcohol.ETCHINGSurface preparation of metal before chemical process. Removal of a layer of the base metal. Usually an acidic substance is used.EXPLOSION VENTPressure relief membrane to prevent damage to a confined dust collection device. EXPLOSION LIMITThe ratio of powder particles to air at which the mixture will explode or ignite EXTENDERPigment that can contribute specific properties to a coating, but usually does not substantially affect the colour.EXTRUDATEMolten powder coating mixture as it exits the extruder during the manufacture process.EXTRUDERDevice used to melt and mix the raw materials to make a powder coating. An extruder utilises heat and mixing to mechanically knead the formulation to achieve a homogenous mixture.FADINGGradual loss of colour, due to a chemical or physical change, usually caused by UV light.FAN PATTERNGeometry or shape of the spray pattern.FARADAY CAGE EFFECTA condition that may exist on a component due to its shape or configuration, that it may inhibit the electrostatic application of powder particles at the specific localised area, such as cavities and recesses.FATTY EDGEThick film sometimes found on heavily coated work, resulting in a rounded thicker coating on (usually) the lower edge. Sometimes called picture framing.FDAFederal Food and Drug Administration.FEED HOPPERA container that holds the powder for the supply to the guns. Often designed to be fluidised.FERROUSContains iron.FILIFORM CORROSIONCorrosion or creep resembling a thread like structure under the coating, usually from a point of film breakdown or damage. Caused by poor or lack of pre-treatment. FILLERExtender, bulking agent or inert pigment.The coating thicknessFILM INTEGRITYDegree of continuity of a paint film.FILM THICKNESSDepth of cured coatings, usually measure in microns or thousands of an inch.FILM THICKNESS GAUGEInstrument for measuring film thickness.FILM WEIGHTThe weight of powder applied. Also often used as a description of film thickness. FILTERA component designed to remove small particles of contamination from the air supply.FINESSmall powder particles, usually under 10 microns. These particles can cause spray and application problems when in high levels.FISH EYESA large surface depression in a coating film often caused by contamination such as oil or silicone oil.FLAMMABLEEasy to ignite, capable of burning with ease.FLEXIBILITYAbility of a film to be bent without damage or cracking after application to a substrate.A characteristic of metallic coatings to change colour when viewed at different angles.FLOW MEASUREMENT OF SELF-LEVELLINGCharacteristic of a coating allowing it to level into a smooth film of uniform thickness during the cure process.FLOW ADDITIVESubstance added to a formulation to minimise defects and produce a uniform film. FLUIDISEDA term that describes powder that is in a state of suspension using compressed air, creating a fluid mixture of air and powder.FLUIDISED BEDA container in which powder is suspended in a continuous stream of air.FUSIONThe melting and flow of individual powder particles under the influence of heat to form a continuous film.FUSION POINTThe temperature at which the powder is melted to form a liquid film, before it begins to cure.GGALVANISED STEELSteel coated with a layer of zinc. Can be prepared by dipping the steel into a hot bed of zinc or applied by electro deposition.GASSINGAir or gas that escapes from as sub surface beneath a coating and causes blisters, eruptions or bubbles in the coating.GEL TIMEInterval of time required at a given temperature for a powder coating to be transformed from dry solid to a gel like state. Measured in seconds.GLOSSThe degree of reflection of light from the cured film.GLOSS RETENTIONThe ability of a coating to retain its original gloss over time and in adverse environmental conditions.GRAVITY HOPPERA powder container, typically cone shaped design t force powder by gravity to feed a gun or transfer system.GRINDERDevice used to crush or pulverise solid coating chip to powder form.HARDENERCuring agent for thermosetting powder coatings.HARDNESSThe ability to withstand indentation and damage. The toughness of a powder film. HIDING POWERThe extent to which a powder coating masks the colour and pattern of the surface it is applied to at a given film thickness. Affected by colours, pigment strength and formulation.HIGH VOLTAGE CABLEA specially designed cable that carries high voltage from generator to gun.HIGH VOLTATE GENERATORAn electrical power transformer that converts 220 – 250 volts AC (Alternating current) current to high voltage DC (Direct current).HOSEFlexible tube used to convey either powder from hopper to gun or compressed air to gun.HUMIDITYA measure of the amount of moisture in the air.HYBRIDA powder coating product formed from a mixed binder of Epoxy and Polyester, also known and Epoxy/Polyester.IMMISCIBLEIncapable of being blended. Components that cannot be mixed together.IMPACT FUSIONThe tendency of powder to form a hard mass upon impact with a surface. Often the cause of blockages and contamination.INCOMPATIBILITYInability to mix two powders without getting a different surface appearance, such as gloss reduction or craters.INFRARED (IR)Light Energy used in short wave or medium wave forms to initiate cure in a powder coating.INFRARED CUREA method of curing powder using direct exposure to light energy from the infrared spectrum.INORGANICA substance that is not formed by natural growth.INSOLUBLEA substance that will not dissolve in water or solvent.INTEGRAL CHARGINGA powder gun that has a low voltage single supply to it, and steps u the current to high voltage via a cascade multiplier located in the gun barrel. This then provides electrostatic charging of powder particles.INTERCOAT ADHESIONThe ability of a powder coating to adhere to a previously applied film.IRON PHOSPHATING CONVERSION COATINGChemical deposition on steel promoting corrosion protection and improving adhesion, converting the steel surface to a phosphate surface.ISOCYANATE RESIN URETHANE RESINSIsocyanate curing agents which when heated or reacted with hydroxyl functional polymers giving urethane coatings.KIBBLE (SEE ALSO CHIP)The result of braking extruded powder coating after cooling.KIBBLERThe machine that makes kibble (chip) from solid and cooled extruded powder coating.LEVELLINGAbility of a film to flow out to a smooth uniform thickness. LOW FILM BUILDThin coating of powder.MANDREL BEND TESTPhysical bending test for evaluating flexibility of a coating. It is an ISO and ASTM test.MASKINGCovered area of a part to prevent coverage by powder during application. MASKING TAPEAn adhesive tape made for easy application and removal to cover areas where coating is not to be applied.MATERIAL UTILISATIONThe percentage of powder that actually is deposited on the parts.MAXIMUM LOADING DENSITYThe maximum number of parts that can be loaded onto a conveyor to ensure optimum powder utilisation.MELT MIXINGA predominant process for the manufacture of powder coatings involving continuous compounding of pigment, resin, fillers, additives and hardeners, mixing at elevated temperature. This takes place in the barrel of the extruder.MELTING POINTThe temperature at which a finely divided powder will begin to melt and flow. MEMBRANEA fine (usually porous) substance separating adjacent parts of equipment. METAMERISMA visual characteristic that describes a coating that appears different in colour when viewed under different lights.MICRONOne millionth of a metre. Used to express applied film thickness.MILOne thousandth of an inch. 25 micron equivalent used mainly in the USA.MILD STEELStructural Steel or plate malleable iron based alloy. SEA 1020 with a carbon content of up to 2.5%.MILEAGEA term used to describe the area covered by a given amount of powder, usually measured in “square metres per kilo” or “pounds per square foot”.MILL SCALE OXIDELayer formed on steel by hot rolling process.MISCIBLECapable of mixing or blending.MISSESVoids in the cured coating.MOLECULEThe smallest particle of a substance that can exist and still retain the properties of that substance. Molecules consist of two or more atoms.MONOMERA molecule that can be chemically bound as a unit of polymer.MSDSMaterial Safety Data SheetNON – FERROUSA material containing no iron.NON-FLAMMABLEWill not burn.NON-VOLATILE SOLIDWill not evaporateNYLON THERMOPLASTIC POWDERSCoating that contains long chain polymers consisting of recurring amine groups (CONH). These coatings are tough, abrasive resistant and exhibit good chemical resistance.OEMOriginal Equipment ManufacturerOFF-COLOURNot matching the colour standard to which the coating is being compared.OHMA unit of electrical resistance.OPACITYAbility to hide the substrate at a given film thickness.ORANGE PEELA wavy irregularity in the surface of a coating film created by the flow characteristics. Orange peel appears as an uneven or rough surface to the eye, but usually feels smooth to the touch.ORGANICSubstance containing carbon, hydrogen and oxygen components.OSCILLATORDevice for moving automatic guns in a vertical plane to provide uniform and increased powder coverage.OVENChamber or enclosed area for the purpose of curing the coating by heat or other energy source.OVERBAKEApplying more heat or energy than is required to fully cure the powder coating. Overbaking can result in discolouration, loss of gloss or deterioration on mechanical properties.OVERCOATApplying a second coating of powder.OVERSPRAYMaterial that does not deposit on the component and goes to the recover system.PPARTICLE SIZEThe average diameter / size f particles in a powder coating, following the grinding process.PASSThe motion of a spray gun in one direction only.PASSIVATIONConversion of a metal surface to a less reactive state. A process to reduce corrosion rate of metal surfaces.pH VALUEMeasurement of acidity or alkalinity. pH 7 is neutral, values greater than 7 are alkali, less than 7 acid.PHOSPHATETo form a thin film of inert phosphate on the metal surface. Process to reduce the rate of corrosion.PIGMENTParticles in a powder coating formulation that provides the colour, corrosion resistance and other properties.PINHOLESFormation of small holes through to the substrate. The appearance of the fine pimply defects in a cured film.PINPOINT DIFFUSERPowder gun tip, which yields a concentrated pattern.PLASTICOne of many high polymeric substances, including both natural and synthetic rubber. At some stage in its manufacture or refinement every plastic is capable of flowing under heat and pressure to form its final shape.PLASTISOLFilm former containing resin and plasticizer with no solvents that forms a tough resistant thermoplastic coating.POLYESTERA resin (binder) containing the grouping R-COOC-R. A polyester has excellent resistance to UV light.POLYETHYLENEResin with the formulation CH2CH2 used in thick film thermoplastic powder coatings. POLYMERSPoly = many: mer = units, Polymers are very large molecules built up by the combination of many smaller molecules, often having many thousand molecules. POLYMERISATIONChemical reaction in which smaller molecules combine to form a high molecular weight polymer.POLYPROPYLENEOne of many polyolefin thermoplastics. Usually in exterior quality thermoplastic powder coating.PVCPolyvinyl Chloride. Synthetic resin used in both liquid and thermoplastic powder systems.POROSITYA porous material will allow liquid or air to pass through. Degree of integrity or continuity.POST CUREHeating an object after application of the powder coating to achieve cure.POST HEATHeating of an object after application of the powder coating.POURABILITYThe ability of a dry powder to flow uniformly or to be continuously poured from container at a steady flow.POWDER BOOTHAn enclosure used for containment of powder coatings during the spray application. POWDER PARTICLEThe smallest single piece that results after grinding powder chip.POWDER SEGREGATIONSeparation of power particles (due to size) during the spray operation and recovery system. Due mainly to the force of gravity, speed and electrostatic deposition. Resulting effect can be changes in gloss or changes in the degree of “orange peel”. PREHEATHeating the component before the application of the powder coating.PRESSUREForce per unit area relative to atmospheric pressure. Usually expressed in psi (pounds per square inch).PRESSURE DROPLoss in pressure usually due to length or diameter of piping or hose. Can be caused by blocked filters.PRESSURE GAUGEA gauge to determine the delivered pressure of a gas or fluid.PRE-TREATMENTThe preparation of a part (component / substrate) prior to powder coating to improve adhesion and corrosion resistance. Often used as a term to describe, phosphated or chromated surfaces.PRIMERA type of coating applied to the substrate surface to improve protection and enhance adhesion of a subsequent topcoat. A primer improves corrosion resistance, hiding power, surface smoothness.PROFILE DEPTHAverage distance between the top and bottom of valleys on a surface. Used as a measure of effective blast cleaning.PSDParticle Size Distribution. The range of particle sizes in the manufactured powder coating.PURGINGCleaning one colour or powder formulation from all areas that come in contact with the powder coating before introducing a new powder.RRADIATION CURECuring a coating by means of exposure to electromagnetic waves or particles such as infrared or ultra violet, or electron beam.RATIORelationship in quantity or size between 2 things.RECIPROCATORDevice used to move automatic guns up and down in a vertical plane.RECLAIMThe process of collecting over-sprayed powder and re-cycling it in the coating equipment.RECLAIM POWDERPowder that has been oversprayed and collected for reuse.RECOATThe process of refinishing parts that have a surface defect from the first coat. Application of a second coat after correction of the defect in the first coating. RECOVERYThe process of removing non-deposited powder from air prior to re-cycling the powder through the delivery system.RECOVERY SYSTEMA filtration system that separates powder from the air stream to capture the overspray powder. Most common types are the cyclone or filter (cartridge) system. REFLECTANCEA measure of the brightness of light reflected from a coating surface.。