Powder Coating 101
TECHNICALHELP4UPowder Coating Made EasyPowderCoating101
TECHNICALHELP4UPowder coating made easy: Powder Coating 101 2001 - 2003 TechnicalHelp4U399 N. Main St Suite FThiensville, WI 53092www.TechnicalHelp4U.com
INTRODUCTION1WHAT IS POWDER COATING?2Why should we use Powder Coatings? 3How are Powder Coatings Made?4Powder Coating Types: ThermosetPowder Coating5Powder Coating Chemistry: ThermoplasticPowder Coating5Thermoset Powder Coating Types:Urethane Acrylic9Thermoset Powder Coating Types: GMAAcrylics9POWDER COATING HEALTH &SAFETY11General Powder Coatings Health andSafety Points:12POWDER COATINGPRETREATMENTThe Importance o f CleaningThe Fundamentals of CleaningCommon Chemical CleaningConversion CoatingZinc PhosphatizingHow to PhosphatizeRinsingPOWDER COATINGAPPLICATION141516161819202022Powder Coatings Application:Application Equipment22Fluidized Bed22Electrostatic Powder Spray Coating24Electrostatic Powder Spray Coating,Corona Gun.24Electrostatic Powder Spray Coating,25Electrostatic Powder Spray Coating, TriboGun.27Electrostatic effectiveness28Operation Conditions29Powder Booth31Powder Fines35Heating Applications In Powder Coatings35Preheating36Postheating - Product Cure36Postheating - Process Considerations 37Postheating - Hot Air, Gas or ElectricConvection Cure37Postheating - Infrared Radiation38Postheating - Ultraviolet Light & ElectronBeam38Oven Exhaust39Oven Residue40Our thoughts on ovens:41Gas or Electric (convection and IR),44Oven Efficiency44What about UV44What about Temperature and Energy? 45Application Conditions:46Excess Heat46POWDER COATING QUALITYCONTROL48Evaluating finished film properties andspecifications48SPECULAR GLOSS49DIRECT/REVERSE IMPACT50VISUAL COLOR51DRY FILM THICKNESS52FILM HARDNESS BY PENCIL TEST 53MANDREL BENT TEST(FLEXIBILITY)54ADHESION55SOLVENT CURE5610 STEPS TO SUCCESSFULPOWDER COATING5710 Steps to Successful Powder Coating 57Why should I use powder coating?59How long have powder coatings beenaround?59What is the difference betweenThermoplastic59What Powder Coating Chemistry should Ibuy?60What about Porcelain enamel60How should I prepare my parts forpowdercoating?60How do I spray Powder? What makes itstick?61Why do I need a spray booth? How is thepowder reused?61
What about curing ovens?61What is Transfer Efficiency?62Can I recoat parts? How?62Can I strip Powder coatings? How?62Care of Powder Coated Parts.62How do I change over from one powder toanother without contamination?63What is a Datapaq64Scratch and Dent Fillers66What maintenance does a powder systemneed?67Tell me about grounding and powdercoating:67Efficiency reasons for grounding.67How can I test for sufficient ground68Obtaining good groundCan I use powder as a primer for liquidcoatings? How?Can I touch up powder coatings?How do I take care of color standards?Where do I begin? What do I need topowder coat?Powder Application Rooms.What can I powder coat?68697070717175POWDER COATING SPECIALEFFECTS76Spices:Applying metallicsBonded/non Bonded powdersDeep Candy AppleCandy ApplePOWDER COATINGTROUBLESHOOTING767778808182Sintered Powder83Proper powder application83Dead Bed - No air percolating throughpowder surface83Dusting - Powder blowing out of hopper84Stratification - Powder separating intolayers of fine and coarse particles84Poor powder feed84Impact fusion - Hard buildup in feed tubesand orifices85Contamination in reclaim powder85Geysering - Air blowing large holesthrough surface of powder.85Powder drifting from spray booth86Inadequate powder buildup and/orwraparound on parts86Poor penetration into corners and recessed(Faraday Cage) areas87Back ionization - powder is repelled frompart in spots87Static charging - powder picks up arandom charge through powder hoses 88Spurting, surging, or puffing - interruptedpowder feed88Gloss too high for a low gloss typepowder89Gloss too low for high gloss type powder89Contamination in powder90Inconsistent film thickness90Excessive Orange Peel90Off color91Pinholing, outgassing and craters throughcoating surface91Pull-away or tearing - coating filmshrinks, leaving bare substrate92Poor impact resistance and/or flexibility92Poor corrosion resistance92Poor adhesion92Poor pencil hardness/poor abrasionresistance93Charging Theory93Faraday Cage Effect94Back Ionization95Gun Nozzles, Tips and Deflectors96SUPPLIER LISTINGTop Suppliers:PowderPowder CoatingsElectrostatic Spray EquipmentPretreatment SuppliersCure Oven SuppliersLube Equipment for ConveyorsPaint Striper ManufacturersKV MetersVacuum CleanersMasking SuppliesTouch Up PaintProduction RacksGloss Meters97979797100101101102102103103103104104104
P O W D E RC O A T I N G1 0 1IntroductionPowder coatings is a great industry. Powder has ran through our veins for over 16years, it is not new to us and we have literally done every single job associated withthis industry with the exception of the raw material side. Our contributors haveformulated, manufactured, developed, managed, troubleshoot, applied andconsulted. Powder can make you laugh and it can make you cry. This manual istargeted at the person who wants to do it right. The person who is tired of gettingrejects and field failures on their parts. Where applicable, shortcuts and moneysaving tips are incorporated. However, at no time do we cut out safety or quality.These are the traits of a successful manufacturer. If you want to do it cheap anddon’t care about safety or quality, then we suggest you read no further. We wishyou good luck.Over the years we have seen entrepreneurs with barely enough money for rentand a powder gun become millionaires and seen millionaires with huge facilities gobankrupt. Where you end up is directly proportional to how seriously (and attimes - unserious) you take this business.Regardless of your current skill level in the industry, you will find this manual willserve your needs. From the novice hobby coater to the OEM applying millionsof pounds annually, this manual has valuable information for you.Powder Coating can fall into the following categories:- Powder coating for hobby- Powder coating job shop- Powder coating for an OEMEventually we end up crossing into each category. Every single powder coatingline at one time or another is used for hobby, or 'government' work. Job shopsmay end up making certain parts for sale which they sell outright becomingOEM"s. OEM's may have excess line capacity which they end up using to do jobshop work.Research is imperative when deciding which industry you will serve with powdercoating. Find your niche, do quality work at a reasonable price and you will besuccessful. Some areas which are hot right now include refinishing wheels, coatingtemperature sensitive parts such as wood or plastic and doing OEM work-1 -
P O W D E RC O A T I N G1 0 1Chapter1What is Powder Coating?Although powder coating has been used for over 30 years, it hasonly been over the past decade that powder has hit mainstream usein industry, hobbies and art.Powder Coating is basically a dry paint. Instead of being dissolved orsuspended in a liquid medium: such as, solvent or water, powder is appliedin its dry form, finer than ground pepper, courser than flour, directly to thesurface to be coated.Each powder particle contains resin, pigments, modifiers, extenders and if it is areactive system, a curing agent. Most powder coatings are reactive and containcuring agents.The term for these reactive powder coatings is: ThermosetThe term for the non-reactive powder coatings is: ThermoplasticIngredients used in the manufacture of powder coatings.-2 -
P O W D E RC O A T I N G1 0 1Why should we use Powder Coatings?Powder Coating offers a number of significant advantages:* Absence of solvents* Applied in one coat - high standard of finish with good edge coverage* Few rejects* Resistant to chipping, scratching, abrasion and bending* Easy to apply* Cleaner working conditions* Virtually no atmospheric pollution, very little or 0% VOC!* Safety in use and on storage, low fire hazard* Insurance premiums may be lower* No viscosity adjustments* Savings in overall costs possiblePowder coatings are electrostatically applied to parts using either a fluidized bed orelectrostatic spray. The part to be powder coated is grounded and the powder ischarged, this attracts the powder to the part, much like a magnet attracts steel.This charge holds the powder to the part and the part is then cured (baked) in anoven. A typical cure cycle would be 15 minutes at 380 F. Cure cycles always referto the amount of time the part is at the temperature specified, not how long it is inthe ovenDue to the significant advances in formulating, manufacturing and applicationtechnologies over the past 15 years powder is used in many areas previously notthought possible.Powder coatings are daily applied in shops ranging from custom job shops to theworld's largest manufactures. Metal, plastic, wood, composite and glass substratescan be coated provided the part does not deteriorate or distort at the curetemperature of the powder. Current low temperature technology allows for curein the 250F range.Office Furniture, General Metals, Engine Parts, Light Fixtures, Industrial Shelving,Computer Cases, Toolboxes, Medical Equipment, Barbeque and Gas Grills,Appliances, Ceramic bottles, Ceramic flash/instrument bulbs, Ceramic roofing tile,Wooden toilet seats, Kitchen cabinets, Home-office furniture, Outdoor grill tables,Children's furniture and many other items can be successfully powder coated.-3 -
P O W D E RC O A T I N G1 0 1How are Powder Coatings Made?Powder coatings are manufactured using an extruder, or compounder, which meltmixes the raw materials together. This mixed material is then flattened and cooledand then subsequently ground down to the appropriate particle size forapplication.This is an example of an extruder used in the manufacture of powder coatings.This particular one is manufactured by APV.This is an example of a grinder used in the manufacture of powder coatings.This particular one is manufactured by PPS in England.-4 -
P O W D E RC O A T I N G1 0 1Powder Coating Types: Thermoset Powder CoatingThermosetting powders are primarily composed of relatively high molecularweight solid resins and a crosslinker. The primary resins used in the formulationof thermosetting powder are:* Epoxy* Polyester* AcrylicThese primary resins are used with different crosslinkers to produce a variety ofpowder coatings. There are many crosslinkers used in powder coatings, includingamines, anhydrides, melamines, and blocked or non-blocked isocyanates. Someformulations also use more than one resin in hybrid formulations.When a thermoset powder is applied and subjected to heat it will melt, flow andchemically crosslink to form a finished film. Chemical reactions during the curingcycle create a polymer network which provides excellent resistance to coatingbreakdown. Once cured and crosslinked, this polymer network will not melt andflow again if heat is applied.Powder Coating Chemistry: Thermoplastic Powder CoatingThermoplastic Powders do not chemically crosslink upon application of heat, butmelt and flow over the part in the oven. As the part cools, after exiting the oven,the film hardens, but will remelt upon application of sufficient heat. The primarytypes of thermoplastic powders are:* Polyethylene* Polypropylene* Nylon* Polyvinyl Chloride* Polyester* Polyvinyledene flurides/fluorcarbonsThermoplastic powder coatings are based on thermoplastic resins of highmolecular weight. The properties of these coatings are dependent on the basicproperties of the resin. These tough and resistant resins tend to be difficult, aswell as expensive, to grind to the very fine particles necessary for the sprayapplication and fusing of thin films. These systems are used more as thickercoatings of many mils thickness and are applied mainly by fluidized bed technique.Most powder coaters do not apply these.-5 -
P O W D E RC O A T I N G1 0 1Thermoset Powder Coating Types: Epoxy Powder CoatingsThe epoxy family of powder coatings is the most prominent type of thermosettingpowder in use today. The listing of available epoxy formulations is quiet extensivebecause of the wide formulating latitude that exists. These materials, as is allthermoset powder coatings, consist of resins, crosslinker or hardener, reinforcingfillers, pigments, processing aids, flow agents and other modifiers. A change in thetype or the amount of any one of these constituents can noticeably change theproperties and performance characteristics of the final product.Epoxy powder coatings are generally custom formulated to the specific decorativeand performance requirements of a given end use. Unfortunately, the epoxy resinbased powder coatings have two major deficiencies - they discolor if overbakedand chalk on exterior exposure.Typical Applications include: Fire Extinguishers, Toys, Mixers & Blenders, OilFilters, Shelving, Dryer Drums, Fertilizer Spreaders, Refrigerator Racks,Microwave Ovens, Primers, Tools, Kitchen Furniture.Thermoset Powder Coating Types: Epoxy Hybrid Powder CoatingsThis group of powder coatings could be considered part of the epoxy familyexcept that the high percentage of polyester (or Acrylic) utilized (often in excess ofhalf of the resin) makes that classification misleading. Property wise, however,these hybrid coatings are more closely akin to epoxies than polyesters, with a fewnotable exceptions. They show similar flexibility in terms of impact and bendresistance, but are slightly softer in pencil hardness - H to 3H being characteristic.Their corrosion resistance is comparable to epoxies in many cases, but theirresistance to solvents and alkali is generally inferior.A major advantage of these hybrids, due to the influence of the polyester or acryliccomponent, is a higher resistance to overbake yellowing in the cure oven. Thisalso translates to improved weatherablilty. These systems will begin to chalkalmost as fast as an epoxy, but the deterioration is slower and the discoloration lesssevere. These systems also have excellent electrostatic spray characteristics withhigh transfer efficiency and penetrate well into corners and recesses.Typical Applications include: same end use as epoxies, especially if a slightimprovement in heat stability or weathering is required.-6 -
P O W D E RC O A T I N G1 0 1Thermoset Powder Coating Types: Polyester Powder CoatingsPolyester powder coatings can be broken down in three groups:Polyester Urethane: Hydroxyl functional resin cured with a blocked IsocyanuratePolyester TGIC: Carboxyl functional resin cured with Triglycidyl IsocyanureatePolyester TGIC Free: Carboxyl functional resin cured either withTetramethoxymethyl Glycoluril or with BetahydroxyalkylamideAll three types of Polyester powder coatings have very good exterior weatheringproperties and are generally used for outdoor applications.Thermoset Powder Coating Types: Polyester Urethane PowderCoatingsThe primary type which has been in use for the past number of years is a urethanecured polyester powder which is comparable chemically to the exterior qualityurethane paints which have been used on aircraft, buses, trucks and railroad carsfor the past 17 years.Coatings of this type combine outstanding thin film appearance and toughnesswith excellent weathering properties. They are true competitors to high qualityliquid paints, exhibiting superior chip, mar and scuff resistance at 1.5 milsthickness. Adhesion to properly prepared ferrous and nonferrous metals isexcellent, providing long term resistance to humidity and salt spray.These formulations must reach a temperature of at least 360 F before crosslinkingcan occur. This is due to the fact that the curing agent is blocked with eCaprolactam to prevent cure at ambient temperatures. These powders aresensitive to films thicker than 3 mills due to the fact that the e-Caprolactamevolution can cause outgassing at thicker films.Thermoset Powder Coating Types: Polyester TGIC PowderCoatingsThis type of polyester is based upon technology developed in Europe. Theseproducts can best be described as more exterior durable cousins of the epoxypolyester hybrids - the difference being that instead of using a conventional epoxyresin to co-react with the polyester, a very low molecular weigh glycidal or epoxy-7 -
P O W D E RC O A T I N G1 0 1functional, curing agent is used.Overbake color stability, as with epoxy polyesters, is also excellent. Their adhesionand corrosion resistant properties are comparable to the urethane cured polyester,but their resistance to chemicals and solvents is lower. A significant advantage isthe fact that these can typically be cured at lower temperatures, for shorter periodsthan urethane or TGIC Free systems. Cure cycles as low as 6 minutes at 300 F areattainable. TGIC formulations also provide good overbake and outgassingcharacteristics making them friendly to apply.The higher melt viscosity of the TGIC crosslinker also results in good edgecoverage and tough thick films, but also results in a slight orange peel effect.Thermoset Powder Coating Types: Polyester TGIC Free PowderCoatingsThese formulations were developed in response to industry concerns regarding thepossible side effects from overexposure to the curative Triglycidyl Isocyanurate.These exhibit similar performance and application properties as TGICformulations do.With TGIC Free formulations it is possible to develop the much desired 'wrinkle'texture effect. An increased resistance to film discoloration and yellowing of thecoating is realized with these formulations.Example of a toolbox coated with a wrinkle powder coating. Kennedy Mnfg.-8 -
P O W D E RC O A T I N G1 0 1Thermoset Powder Coating Types: Acrylic Powder CoatingsAcrylic formulations give excellent exterior durability. There are twoclassifications of acrylic formulations. Urethane Acrylic and GMA Acrylic.Thermoset Powder Coating Types: Urethane AcrylicThese formulations are similar in properties to Polyester Urethane products,offering excellent thin film appearance, good chemical resistance and hard durablefilms. The flexibility and impact of these is very poor due to the high crosslinkdensity of the cured film.Thermoset Powder Coating Types: GMA AcrylicsThese are also similar in properties to Polyester Urethane products. They makeexcellent clear coats over brass and chrome, being ideal for bath fixtures andautomotive wheels. These however also exhibit poor flexibility and moreimportantly are highly incompatible with all other powder chemistries. Thisrequires the manufacturers and users to utilize isolated systems to prevent crosscontamination.Comparison of PropertiesHybridPolyesterUrethaneAcrylicPolyester TGIC& TGIC FreeHB - 7HHB - 3HHB - 4HH - 4HHB - 4H40 - 160 40 - 16040 - 160 40 - 10040 - 160 3 - 100 10 - 100 5 - 9510 - 9010 - 951,000 hrs.1,000 hrs.1,000 hrs.1,000 hrs.1,000 hrs.Salt Spray1,000 hrs.1,000 hrs.1,000 hrs.1,000 hrs.1,000 hrs.Cure Range3 min @ 450F 25 min @ 250FChemistryEpoxyPropertyPencil HardnessImpact Resistance(in - lbs)Gloss(60 Degree Meter)CondensingHumidity10 min @ 400F - 10 min @ 400F - 10 min @ 400F 25 min @ 300F 20 min @ 360F 25 min @ 350F10 min @ 400F 30 min @ 300FThese products are available in all color shades and a variety of textures.-9 -
P O W D E RC O A T I N G1 0 1Comparison of Properties ry good chemicalresistanceWater Heaters, RadiatorsTransformer covers,Office Furniture, Shelving1(least expensive)Excellent chemicalresistance & propertiesPoor exterior color/glossretentionGood chemical resistanceVery good mechanicalproperties & exterior colorgloss retentionVery good chemicalresistancePoor flexibilityMetal Furniture, AutoParts, Microwave Ovens,Shelving, Appliances2Automotive Wheels, Lightfixtures, Above GroundLP Containers3Oven Parts, WashingMachines, AluminumExtrusions- 10 -4(most expensive)
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Powder drifting from spray booth 86 Inadequate powder buildup and/or wraparound on parts 86 Poor penetration into corners and recessed (Faraday Cage) areas 87 Back ionization - powder is repelled from part in spots 87 Static charging - powder picks up a random charge through powder hoses 88 Spurting, surging, or puffing - interrupted
4:30 - 6:30 PM Powder Coating 2022 Tabletops & Reception TUESDAY, MARCH 8 Powder Coating 101 Workshop, Powder Coating 2022 Technical Conference & Tabletop Exhibition 7:00 AM Registration Opens 8:00 - 8:30 AM Breakfast for Workshop 8:30 - 11:30 AM Powder Coating 101 Workshop 8:30 - 9:30 AM Technical Conference Breakfast
4. Running an Efficient Powder Coating Line New Economical Fast Color Change System Allows Powder Coater to Minimize Lead Times Carl Troiano, Trojan Powder Coating Frank Mohar, Nordson Corp. Carl Troiano, owner of Trojan Powder Coating, will discuss his new economical fast color change system and how it has helped increase his productivity by .File Size: 2MB
powder coating. SUMMARY This eBook reviews the range of available powder coat finishes and discusses the numerous benefits of working with a manufacturer with in-house powder coating capabilities. Powder coating is a common practice because it's one of the most effective ways to paint a wide range of industrial products. Over the
Powder Coating is a type of coating that is applied as a free-flowing, dry powder. The main difference between a conventional liquid paint and a powder coating is that . Trojan and Gem Type Automatic Plant Vulcan Lat
This guide specifically covers those for powder coating. High temperatures Chemical Stripping Electroplating Anodizing . Powder coating is a finishing process that's applied as a dry, free-flowing thermoplastic or thermoset powder to a surface, melted, and then hardened into an even coating. It's suitable for various materials,
Uniform coating thicknesses are easily achievable despite thickness variations of the substrate. In particular, Halar powder coating offers many unique advantages. Final thickness of Halar powder coating normally varies from 0.2 to over 2 mm. Coatings greater than 1 mm are termed "High Build" coatings. The Halar powder application bake .
MnDOT Powder Coating Qualification Testing Procedure. The test procedures contained herein describe the process for submittal, testing, and evaluation of powder materials for use in MnDOT powder coating applications. Applied powder materials which meet or exceed the stated perfor
The U.S. Army Combined Arms Command is the proponent for this publication. Send comments or suggestions to the Deputy Commanding General for Training, Combined Arms Command, ATTN ATZL-CTT, Fort Leavenworth, KS 66027-7000. Unless this publication states otherwise, masculine nouns and pronouns refer to both men and women. 1 Chapter 1 The After-Action Review DEFINITION AND PURPOSE OF AFTER-ACTION .
