Technical Data - Cooper Industries

1 FinishesZinc CoatingsZinc protects steel in two ways. First itprotects the steel as a coating, andsecond as a sacrificial anode to repairbare areas such as cut edges, scratches,and gouges. The corrosion protection ofzinc is directly related to its thickness andthe environment. This means a .2 milcoating will last twice as long as a .1 milcoating in the same also protects cut and drilled ZincElectrogalvanized Zinc (also known as zincplated or electroplated) is the process bywhich a coating of zinc is deposited onthe steel by electrolysis from a bath ofzinc rating of SC3, our standard, provides aminimum zinc coating thickness of .5 mils(excluding hardware, which is SC1 = .2mils).When exposed to air and moisture, zincforms a tough, adherent, protective filmconsisting of a mixture of zinc oxides,hydroxides, and carbonates. This film isin itself a barrier coating which slowssubsequent corrosive attack on the coating is usually recommended forindoor use in relatively dry areas, as itprovides ninety-six hours protection insalt spray testing per ASTM / Zinc Chromium / Zinc is a corrosion resistantcomposition, which was developed toprotect fasteners and small bulk items forautomotive use.

2 The coating applicationshave since been extended to larger partsand other markets. Chromium/Zinc composition is anaqueous coating dispersion containingchromium, proprietary organics, and zincflake. This finish provides 500 hours protectionin salt spray testing per ASTM Zinc(Mill galvanized, hot dip mill galvanizedor continuous hot dip galvanized) Pre-galvanized steel is produced by coatingcoils of sheet steel with zinc bycontinuously rolling the material throughmolten zinc at the mills. This is alsoknown as mill galvanized or hot dip millgalvanized. These coils are then slit tosize and fabricated by roll forming, shear-ing, punching, or forming to produce ourpre-galvanized strut G90 specification calls for a coatingof .90 ounces of zinc per square foot ofsteel. This results in a coating of .45ounces per square foot on each side ofthe sheet. This is important whencomparing this finish to hot dip galvanized after fabrication, cut edges and weldedareas are not normally zinc coated;however, the zinc near the uncoatedmetal becomes a sacrificial anode toprotect the bare areas after a short periodof Dip Galvanized AfterFabrication (Hot dip galvanized orbatch hot dip galvanized)Hot dip galvanized strut products arefabricated from steel and then completelyimmersed in a bath of molten zinc.

3 Ametallic bond occurs resulting in a zinccoating that completely coats all surfaces,including edges and advantage of this method iscoating thickness. Strut products that arehot dip galvanized after fabrication have aminimum thickness of ounces persquare foot on each side, or a total per square foot of steel ,according to ASTM zinc thickness is controlled by theamount of time each part is immersed inthe molten zinc bath as well as the speedat which it is removed. The term "doubledipping" refers to parts too large to fit intothe galvanizing kettle and must be dippedone end at a time. It does not refer toextra coating layer of zinc which bonds to steelprovides a dual protection againstcorrosion. It protects first as an overallbarrier coating. If this coating happensto be scratched or gouged, zinc'ssecondary defense is called upon toprotect the steel by galvanic Galvanized After Fabrication isrecommended for prolonged outdoorexposure and will usually protect steel for20 years or more in most atmosphericenvironments and in many industrialenvironments.

4 For best results, a zincrich paint (available from Eaton s B-LineBusiness) should be applied to field zinc rich paint will provide immediateprotection for these areas and eliminatethe short time period for galvanic actionto heal the damaged Life of Zinc Coatings In Various Atmospheric EnvironmentsHot Dip GalvanizedPre-Galvanized= Zinc Coating (.0026 Thick)= Zinc Coating (.00075 Thick)RuralTropicalMarineTemperatureMari neHighlyIndustrialLifeinYearsSuburbanEnv ironmentUrban102030401036829725621518311 ZnFeZnFeZnOTechnical DataTechnical Data6 Strut SystemsDURA GREEN and DURA-COPPER Epoxy CoatingsDURA GREEN and DURA-COPPER epoxycoatings are water borne epoxy coatingsapplied to Our products by a preciselycontrolled cathodic electro-depositionprocess. This process is accomplishedusing a conveyor to transport channel and fittings through several cleaning,phosphatizing and application stages priorto being baked (See diagram below).This custom-designed paint system isused for painting all channels, channelcombinations, slotted angle, and are selected on a routine basisfor Salt Spray (fog) testing to verify thequality of the finish.

5 These tests areperformed in accordance with ASTM B117and evaluated and related according toASTM D1654 (Tables 1 & 2). The DURA GREEN and DURA-COPPER epoxy coatings have been tested andlisted by Underwriters Laboratories inaccordance with Standard for SurfaceMetal Raceway and Fittings, UL5 and Standard for Pipe Hanger Equipment forFire Protection Service, UL203 .Due to DURA GREEN s organically basedcomposition, it seats itself into poroussurfaces more completely and efficientlythan zinc coatings. As these porous caverns are filled along the material profile,the outer finished surface demonstrates anincreased smooth uniform plane whichproduces considerably less off-gasing GREEN channel meets or exceeds100 level clean room standards. This wasconfirmed by testing the channel inaccordance with Boeing (PCL) Standards,which are more stringent and completethan ASTM E595-93. DURA GREEN wasfound to be a superior finish, due in part toits proven application 1/8 ( ) CreepageType of Finish5% Failure (1)from Scribe (1)DURA GREEN Epoxy1000 Hours312 HoursMill Galv.

6 (Pre-Galv.) G90192 Hours288 HoursPerma-Green438 Hours231 HoursZinc Chromate36 Hours96 HoursIndustry Green (Range)10 to 36 Hours4 to 30 HoursSalt Spray Test ResultsDURA GREEN / DURA-COPPER Epoxy Coating ProcessTank 1 Tank 2 Tank 3 Tank 4 Tank 5 Tank 6 Tank 7 Tank 8 Bake OvenThe channel A rinse isA phosphatized The materialA pre-deionized The electro-The firstThe final rinse The curingand parts are applied tosealer is applied moves throughrinse preparescoating tankpost rinseinsures aprocess takes 20thoroughlyremoveto insureclear water rinse the metal for the applies a removes anysmooth,minutes at acleaned and insoluble salts corrosionto remove excess cathodic electro- uniform coatunelectrically nonblemishbaking temperaturephosphatized. and unreacted resistance and epoxy paint 375 F (199 C). the (1) All salt spray (fog) tests conducted in accordance with ASTM B117 and evaluated andrated according to ASTM D1654 Tables 1 & 2. Tests are performed and certified by anindependent testing DataTechnical DataStrut Systems7