Duritan® Manual

Duritan ® ManualWork flawlessly and utilise all thebenefits of the super fast coating system!Edition 02.05.11

SectionTechnical equipmentDuritan ® cannot be processed with allspray devices on account of itsextremely high proportion of solidcontent. Learn more on the followingpages about the devices that aresuitable and why.Starting from page 9Duritan ® dries up and cures very quicklywhen exposed to sunlight. You needspecial lighting equipment so that thisprocess takes place in a controlledmanner.Starting from page 157

Spray devicesDuritan ® cannot be processed with allspray devices owing to its extremelyhigh proportion of solid content9

Choosing the proper spray devices for applying Duritan ® is critical for a clean formationof the film and flawless coating.You can achieve the best results by using spray devices made by SATA. Werecommend either the use of a cup gun or a spray system with a pump and materialhosepipe.It goes without saying that guns of other manufacturers, too, having the same or similarmode of operation can also be considered. Pre-trials are always necessary for thesuccessful use of devices produced by other manufacturers.1. The cup gunThe use of a SATAjet 3000 RP has provenitself. The advantage of the cup gun lies inthe processing of small coating quantitiesfor occasional coating or for coatingsmaller surface areas. The figureillustrates a SATAjet 3000 RP digital withSATA RPS UV black cup.HVLP guns are not so suitable on accountof the coarser atomization!Cup adjustment for the SATAjet 3000 RP:Input pressure minimum 2 bar to 2.5 bar(measured at the gun with the leverdisengaged)Nozzle size 1.2 mm for Duritan ® FillingPrimer DT-F, as well as Duritan ® Deep-MatVarnish DT-TM and 1.0 mm for Duritan ®High-Gloss Varnish DT-HG.The spraying clearance from the nozzle tothe surface should be approx. 25 cm. Donot spray less than 20 cm away!The spraying angle at the gun must be setto the maximum width. (Never changethis!)Alignment of the nozzle always parallel tothe surface; never hold it at an angle!10

2. Spray device with pump and materialhosepipeFor coating larger surfaces or for coatingthe whole day long we recommend the useof a coating system with a feed hosepipein order to be able to apply the coatefficiently and in a fatigue-free manner.The figure illustrates the coating system,SATA ® Vario Top Spray with the gunSATAjet ® 1000K, which is available with ablack flow cup, as well as a solventresistantmaterial hosepipe.HVLP guns are not so suitable on accountof the coarser atomization!Cup adjustment of SATAjet ® 1000K withdouble diaphragm pump SATA ® Vario topspray:Inlet air pressure minimum 2 bar to 2.5 bar(measured at the gun with the leverdisengaged).Material feed pressure 0.5 barNozzle size 0.8 or 1.1 mm for all Duritan ®varnishes.The spraying clearance from the nozzle tothe surface should be approx. 25 cm. Donot spray less than 20 cm away!The spraying angle at the gun must be setto the maximum width. (Never changethis!)Alignment of the nozzle always parallel tothe surface; never hold it at an angle!11

3. Airmix / Airless systemsWe discourage the use of the classicalairmix or airless systems.These systems work with a highcompressed air ratio. The materialpressure goes up from 50 to 120 bar, i.e.the varnish itself gets compressed andejected with this pressure from the nozzle.At the air cap, the relatively hard spray ispost-formed with low-pressure atomizingair of approx. 0.5 to 2 bar, so that no hardspray edges occur and a softer coatingmist hits the surface.Duritan ® is not suited for this sprayingmethod, since it is a High-Solid coatingsystem, which must be atomized with airpressure to a particularly fine level.Exception: Systems without compressedair conversion (1:1), since the coatingmaterial is not compressed here!When using airmix systems for processing,the high material pressure on the surfacecauses foam formation (Micro-foam) and asandy appearance (Macro-foam) of thesurface resulting from the air trapped byvery large separate coating droplets.The figure illustrates a surface having asandy appearance resulting from the useof a coating system not suited for Duritan ® .12

Cleaning the working devicesIMPORTANT:Prior to filling up Duritan ® in your coatingdevice, it is extremely important to ensurethat it has first been rinsed thoroughly withZweihorn ® Univeral Cleanser UR. Forcleaning the spray device subsequently,too, we recommend urgently that you useZweihorn ® Univeral Cleanser UR.While diluting with thinners of third-partymanufacturers, it is possible that theDuritan ® coating mixture gets curedundesirably and this can destroy thecomplete coating system.All Zweihorn ® thinners are made fromfresh raw materials and never producedfrom recycled thinners. This ensuresuniformly pure quality. Hence, anypremature reaction of these thinners withDuritan ® is ruled out.Compressed airNot merely the proper selection of thespray devices is decisive for an optimalspray result.Particularly in the case of High-Solidcoating systems, such as Duritan ® , thequality of the compressed air is extremelyimportant in order to achieve perfectsurfaces.Water and oil residues lead to flaws in thesurface. This can be prevented by the useof appropriate compressed air filters (e.g.,Sata ® Filter 484).13

Exposure devicesDuritan ® coats require sunlight in orderto start the curing process.You can bring this on the surface withthe help of special devices in a targetedand controlled manner.15

SunlightDuritan ® is a coating system that dries withUV-A, i.e., plain sunlight is adequate forcuring it. However, this means that coatedsurfaces or even coating residues andguns must be protected from intensivesunlight.Direct sunlight behind windows may alsocause undesirable curing of the coat (e.g.,if the prescribed evaporation or drying timeshould not yet have been reached).Hence, it is recommended to protect thedevices and tools.Available for the cup guns:Black UV protective cup and cap cover, aswell as a black or white pigmented storagetank for the SATA Vario Top Spray.Tip:If your mixing or painting shop iscompletely protected from direct sunlightor UV light, no black UV protective cupsare necessary.16

Duritan ® exposure panelThe use of the special Duritan ® exposurepanel is recommended, among others, forthe exposure.This simulates the sunlight without emittinga high dosage of the aggressive UV-B andUV-C radiation in the process.It is comparable with an intensive tanningsystem as you know them in solariums.The robust construction and optimiseddesign for the workshop and rack trolleysdrying make it optimal for drying coatings.In addition, apart from the option of wallmounting, it provides the facility of beingmounted on a stable and portable wheeledstand in order to meet the needs in theworkshop.In order to illuminate the edge on the rearside, we recommend that you placereflective walls made of metal, for example(available with the manufacturer of theexposure panel) or an HPL mirror filmbehind the rack trolley (see Figure).17

Duritan ® hand-held lampThe hand-held lamp is a conventional UVspotlight that is also suitable for curingclassical UV varnishes.Special radiation protection is necessaryon account of its high intensity (see pages67-69).A protective sleeve and a metallic storagehousing are included as additionalprotection against stray or scatteredradiation.The exposure with the hand-held lamp hasbeen conceived for small parts as well asthree-dimensional parts that are difficult toaccess.As a result of its high level of radiationdosage, the "retraction" of the coatedsurface with half the coating speed isadequate here during exposure.A cross movement, i.e., each surface iscaptured briefly twice by the light beam isgenerally fully adequate.Tip:Dark substrates require longer exposuretime than light-coloured substrates.Similarly, curing the filler material requiresseveral passes with the UV hand-heldlamp.Attention: Place the hand-held lamp only inthe metallic housing – Fire hazard!18

Maintenance / Service of the exposuredevicesThe Duritan ® exposure devices can worksmoothly when they are cleaned from timeto time, the filters are cleaned regularly orreplaced and the lamps are changed whenneeded.For cleaning orreplacing the tube, theperspex pane can beremoved easily!Cleaning:Clean the perspex pane 1 to 2 times amonth with a wet cloth depending on theincidence of dust (inside and outside).Blow off the filter in the blower (there are 2filters in the exposure panel and 1 filter inthe hand-held lamp) once a week or every 2weeks depending on the incidence of dustwith the compressed air nozzle.Simply unscrew the strip and remove the perspexsheet!Replacement:If the filters can no longer be cleaned in theblower or if they are defective, they must bereplaced.The lamp tubes in the Duritan ® exposurepanel lose power depending on their use (ingeneral, they must be replaced after oneyear at the latest!).The lamp in the hand-held lamp has a verylong service life (naturally, also dependenton the usage).Regular cleaning of the filter or its replacementTip: You can test the power of the tubesand lamps using a special UV tester thatyou can also buy from Panacol. The energyincident on the coated surface must be atleast 1 mWatt/cm² (for the rear edge in therack trolley, 0.3 mWatt/cm² is sufficient,measured at the mirror)Information on protection from radiationand explosion protection is given in thesection on Occupational safety / Safety.Protection against radiation from page 67onwardsExplosion protection from page 71 onwards19

SectionProcessingDuritan ® is a new and patented coatingsystem.The workflows in the production facilitiesmust be modified as a consequence ofthe fast curing. However, since thecoating system also has many peculiarities,it is also necessary that youmodify your working method, e.g., whenmixing the varnish from page 23filling up wooden pores from page 27varnishing from page 33surface compositions from page 39sanding from page 45polishing from page 4921

Mixing the varnishDuritan ® becomes sensitive to light onlyafter adding the activator. You mustcomply with the quantities precisely herein order to be able to create a flawlesssurface.23

General, mixing, pot lifeDuritan ® is a three-pack coating systemwhose chemical cross-linking (curing) isinitiated by low-level UV energy, e.g.,sunlight. The paint and the hardener donot react at first. The system becomesreactive only after adding the activator thatis sensitive to UV light. From this stageonwards, the coating mixture is sensitive toUV light and even sunlight! See also thesection on Exposure.If Duritan ® is mixed under normal roomlighting conditions and stored andprocessed ideally in a container that isprotected against light, the mixture has apot life of at least 6 hours.Please protect the ready Duritan ® mixturefrom UV light, such as, for example, strayor scattered light from the Duritan ®exposure panel or the Duritan ® hand-heldlamp or direct sunlight. The pot life isaffected considerably by UV light. Theextent to which the pot life is affected isdetermined by the intensity and duration ofthe UV rays. In general, it can be said thatthe more and longer the incidence of theUV rays, the faster is the cross-linking andthe shorter is the pot life.Weighing the paintWeighing the hardenerThe figure illustrates the mixing of Duritan ®in a special black cup SATA RPS UV,which can be used directly on the SATAflow cup gun that is compatible with it.Weighing the activator24Stir well!

The mixing procedure:In general, we recommend that the components be mixed by weight.Product Mixing ratio Example Mixing ratio ExampleDT-F 100 parts 1,000 gm 100 parts 1,000 mlDH 1 100 parts 1,000 gm 100 parts 1,000 mlDA 2 2 parts 20 gm 2.5 parts 25 ml*S 9004 optional 5 parts 50 gm 5 parts 50 mlDT-HG 100 parts 1,000 gm 100 parts 1,000 mlDH 1 100 parts 1,000 gm 100 parts 1,000 mlDA 2 2 parts 20 gm 2.5 parts 25 ml*DT-TM 100 parts 1,000 gm 100 parts 1,000 mlDH 1 50 parts 500 gm 50 parts 500 mlDA 2 4 parts 40 gm 5 parts 50 ml**Please use the dosage aid enclosedPlease use the exact dosage quantity of the DA 2 activator.There may be severe surface faults that occur if you do not follow this.25

FillingUsing the Duritan ® Two-Pack PoreSurfacer, depending on the type ofwood, you can save 2-3 coats withclosed-pore structures.27

Filling up wooden poresCoarsely porous woods that need to betreated in a close-pored manner withDuritan ® , can be set up in several coatinglayers with Duritan ® Filling Primer DT-F.Since in certain types of wood, the coatforms around the pore, some open poreswould always remain behind and thus,stop the work process.In order to coat such types of woodefficiently in a close-pored manner, werecommend the use of special Duritan ®Pore Surfacer DT-PS. The pore surfacerconsists of 100% solids, i.e., no volatilematerials such as solvents escape afterfilling, which could cause subsequentsinkage in the pores. Another advantage isthe possibility of being able to expose itimmediately after the filling process withoutany drying off time.Duritan ® Pore Surfacer DT-PS is suppliedin a tube set. The set consists of:• 1 tube with 150 gm of component A• 1 tube with 150 gm of component B• Several wooden spatulas for stirring• 1 piece of plastic spatula28

Please take care to wear proper workclothing prior to using the filler material.Gloves are absolutely essential.Both the components are mixed, forexample, on a clean wooden board in theratio 1:1, and then applied on the workpiece.It is not necessary to activate thefiller additionally, since the activatorrequired is already included in thecomponents. Please take care to avoid theincidence of UV light such as sun rays orscattered (stray) light from the exposurepanel, since Duritan ® Pore Surfacer DT-PSis also sensitive to light and reacts andgets cured by it.It is basically recommended to first apply athin layer (approx. 60 µm) of Duritan ®Filling Primer to the surface.Duritan ® Pore Surfacer DT-PS can beapplied directly on the raw wood, and thefiller can be applied even on stainedsurfaces (with Zweihorn ® stains exceptWax Stain WB).Tip:In order to prevent through sanding of thestained surfaces, after filling the stainedsurfaces, you can apply a coat of Duritan ®Filling Primer DT-F prior to exposing it tolight.Attention:Duritan ® Filling Primer DT-F and Duritan ®Pore Surfacer DT-PS have different grainaccentuation. If all components need notbe treated with Duritan ® Pore Surfacer DT-PS, it is recommended that you do notapply the filler to the raw wood, butinstead, pre-treat it first with a thin coat(approx. 50 to 60 µm) of Duritan ® FillingPrimer DT-F. You can apply the fillermaterial after exposing it to light and afterintermediate sanding.29

Apply Duritan ® Pore Surfacer DT-PS to thesurface and spread the filler film uniformly.The filler is first spread uniformly with thewood grains on the component and next,the filler is "pressed in" across the woodgrain using the plastic spatula. The morecarefully that this step is carried out, thebetter is the subsequent result and fewerare the coats required for furtherprocessing. Above all, attention must bepaid to adequate cross-linking with thefiller at the edges.In the final step, the excess of the fillermaterial is removed with the wood grain.ATTENTION: The excess should beremoved completely. If tracks or increasedcoating thicknesses of Duritan ® PoreSurfacer DT-PS remain behind on thesurface, these cause turbidity at the time oflight exposure. If the filler is coated withoutlight exposure using a coat of Duritan ®Filling Primer, it is very important toremove the filler material with the woodgrain thoroughly, since otherwiseundesirable unevenness can occur on thesurface. If larger area spots need to befilled up, you must either reckon withdiscoloration (e.g., for subsequent colourfulpaint application) or work in severalstages depending on the depth of the spotto be filled with Duritan ® Pore Surfacer DT-PS.Profiled or sectioned components can alsobe treated with Duritan ® Pore Surfacer DT-PS. Here, for example, the material can beapplied and spread using a brush, and theexcess can then be removed using a lintfreecloth. Finally, there are many objectsthat are suitable for applying and removingthe excess uniformly. What is important isto check the working devices beforehandfor their suitability with Duritan ® PoreSurfacer DT-PS. For example, certainrubber coating knives and plastics fade thecolour and may thus leave traces on thesurface.30

The light exposure takes place as usual,either with the hand-held lamp or theexposure panel. Please note here,however, that the exposure time anddrying time is at least double prior tofurther processing. We recommend theuse of the exposure panel since the curinghere is more controlled than when usingthe hand-held lamp.You can do sanding as desired after thecuring and drying time. Please take care toensure that you do not sand right throughotherwise spots may occur. However, if thesurface still gets sanded through, the fillingprocedure should be repeated so thatthere is no variation in the grainaccentuation. The filling procedure isrecommended even with certain woodpores that are difficult to fill. The knowntypes of wood having problematic coarseporedcharacteristics are, for example,Zebrano, Bubinga, Wenge and certaintypes of mahogany.When treating stained surfaces, you musttake care to ensure that you do not sandthrough the surface. After curing, the fillercan either be sanded carefully with theeccentric sander using grain size 320 to400 or sanded manually with an abrasivesponge. Similarly, it is possible that you donot expose the surface to light in case ofstained surfaces and to apply a coat ofDuritan ® Filling Primer DT-F on the surfaceimmediately after removing the excessfiller material and curing it only thereafter.However, here too, you must be "Cautiouswhile sanding".If you cannot sand the surface intensivelyas in the case of stained surfaces here, itis important to continue to work at a rapidpace. This means that you must work withDuritan ® Filling Primer immediately aftercuring and the drying time of the fillermaterial in order to ensure adequateintermediate adhesion. This mustnecessarily taken into consideration in theprocessing workflow.31

VarnishingDuritan ® is the innovative coatingsystem of the future.The three-pack system requires aparadigm shift in varnishing habits andstringent compliance with certainparameters.33

Foreword to varnishingThe actual process of varnishing takes place in the customary manner and requiresthe same occupational safety for the painter as in the case of conventional solventbasedand water-based varnishes.See the section on Ooccupational safety starting from page 58 onwards.Applying coats of Duritan ® varnishes requires the observation and implementation oftechnical parameters that are described in this manual and in the technical datasheets.In contrast to conventional PUR varnishes, the technical parameters are not merelyrecommended values for processing, which permit a large bandwidth inimplementation, but must be strictly complied with.Please observe and follow the section on spray devices starting from page 9 onwardsstrictly.If you are ready to adjust your customary method of working, you will start producingquickly and efficiently, and you can benefit from the new Duritan ® system in theprocess.34

Coating parametersThe most important adjustment when applyingDuritan ® is the atomization of the coatingmaterial. You achieve perfect results only withdroplets of coating material that have beenfinely atomized. If the coating is not finelyatomized, a "sandy" looking surface occurswhile coating. You can recognise this flawedpicture from the fact that it appears uniformlydistributed over the entire surface and itappears as if the sandy surface was causedby dirt particles in the paint or from the workenvironment. However, this is really air thatwas torn by the very large drops of paint andcould no longer escape from the film of paint.Hence, it is extremely important that the sprayappearance is adjusted optimally.The size of the paint droplets can be affectedby the following adjustments:• Nozzle size 1.0 to max. 1.2 mm• Input pressure minimum 2 bar. Themeasurement is made directly at the gun withthe coating lever pulled. An analoguepressure gauge is sufficient that is connecteddirectly in front of the pneumatic connection ofthe gun.• The spray angle must be adjusted to themaximum even if only small edges need to becoated. A smaller angle would again lead tothe formation of paint droplets to larger dropsof paint.• The angle of the spray beam to the objectshould be 180°. Clearance approx. 20-30 cm.• The varnish should be thinned only whenapplying Duritan ® Filling Primer DT-F, if thisappears to be necessary (e.g., for improvingthe pore cross-linking in woods such asMahogany, Wenge, Zebrano, etc.). Themaximum quantity of thinner added must becomplied with in the process.• The processing temperature should not bebelow 15°C.Attention: If you get a poor surfaceappearance, for example, a sandy surface, itdoes not mean that only one wrong adjustmentis responsible for this. Sometimesseveral inconspicuous or insignificant minorwrong adjustments add up and cause a majorproblem.35

Rest time:After the coating process, a minimum rest time of 10 minutes must be complied with.The only exception is Duritan ® Pore Surfacer DT-PS. This surfacer is 100% solid, whichmeans that no solvents need to escape after filling and thus, it can be exposed to lightimmediately.ProductMinimum rest time priorto light exposureRemarksDT-PS omitted 100% solid, hence nodrying necessaryDT-F and DT-HG 10 minutes Air bubbles and residualsolvent must escape priorto light exposure. Theexposure to light shouldcommence only when thesurface appears to be asclear as glass.DT-TM 20 minutes Here, too, air bubbles andresidual solvent mustescape. The exposure tolight should commenceonly when the surfaceappears to be uniformlydeep matt.Light exposure time:All light exposure parameters such as clearance to the surface and proper illuminationare furnished in the section on “Exposure devices" from page 15 onwards.In addition, pay attention to adequate temperature of the coating material and the activesubstances, as well as an ambient temperature of at least 15°C for optimal processingand optimal coating procedure.36

Benefit of the long open timeA great advantage of processing with Duritan ® is that even large surfaces or 3-D partshaving several corners and edges can be coated at leisure.In contrast to conventional coating systems, in fact, a small portion of solventsevaporates at first from the varnish film applied, but however, the varnish itself is curedonly after feeding UV energy. This characteristic has the advantage that no spray mistlies on those parts of the object that have already been coated. If, for example, you arecoating a chair, the painter now has the time to coat it properly and need not worry aboutany addition of a slow thinner or a retarder, since any spray mist falling on the regionsthat have already been coated fuse into one another.Curing overspray with the Duritan ® Overspray Drier DT-OTAfter the coating process, there is an adhesive layer of Duritan ® remaining in thecoating room caused by the over-spray remaining behind. In coating rooms where thereis no incident daylight, these coat residues cure only after several hours. The curing ofthese residual coating materials can be accelerated with the product, Duritan ®Overspray Drier DT-OT to cure them immediately. Depending on the layer thickness ofthe coating film, Duritan ® cures within a matter of minutes. In this manner, the workingdevices such as the spray racks, floors or floor grates and walls do not become tacky.The product is water-based and should be used only to accelerate the curing of spraymist.Attention:• Please process the product only in a clean gun.• Never use it to clean Duritan ® in the spray device. (Risk of deterioration by immediatecuring!)• The product is not suitable to accelerate the curing process on coated surfaces. It isnot an alternative to the exposure panel or the UV hand-held lamp.Tip:Fill up Duritan ® Overspray Drier in a spray bottle. In this manner, the product is alwaysready at hand and is not filled up inadvertently in Duritan ® spray devices.37

Use of suitable filter mats for your suction systemPlease take care to provide and use suitable filter mats for the suction system whenprocessing Duritan ® . Please enquire with the manufacturer of the suction wall regardingthe filter mats best suited for your system.Particles of PUR or NC systems that dry conventionally are extracted by the suctionwall, and depending on the distance to the suction wall and the quantity of spray mist,are more or less relieved of the solvent on reaching the filter mat and are somewhattacky. With this spray mist, the particles are then dust particles that are retained by thefilter mat. If the filters are not suitable or too coarse, the varnish particles enter into thepipes of the suction system usually in dry condition as varnish dust.In contrast to conventional coating systems, Duritan ® spray mist cures without UV lightand only after a few hours. If the filters are too coarse or not suitable, tacky varnishparticles can escape through the filter and collect on the pipe system or on the suctionrotor and cure at the end of the working day and form a film of varnish. This can beprevented by using appropriate filter systems that do not allow varnish particles to passthrough.38

Surface compositionsThere are diverse options for thecomposition with the Duritan ® coatingsystem, even in combination with provenvarnishes from Zweihorn ® .39

Depending on the substrate, we recommend the following varnish compositions:Fine-porous hardwoods such as Beech, Cherry, Pear tree as well as softwoodssuch as Fir, Larch and PineOur recommendations:High-gloss Deep mat Silky glossDT-HG or CL-H DT-TM Crystallit ® or DuocrylDT-F optional DT-F optional DT-F optionalDT-F DT-F DT-FDT-F thin DT-F thin DT-F thinFinely porous wood / raw MDFIn case of highly absorbent types of wood and MDF, it is recommended that you firstapply a thin layer (50-60 µm) of Duritan ® Filling Primer DT-F and cure this in the usualmanner. If the specified maximum quantity is coated on absorbent substrates, the fillerprimer penetrates non-uniformly in the substrate. Thus, clusters and unevenness form onthe coat that require intense sanding and make the surfaces appear uneven.Next, coating continues with DT-F, DT-HG or DT-TM.40

Coarsely porous substrates such as, e.g. Oak, Ash, Zebrano, Wenge andMahoganyDepending on the property of the wood pores, pre-treatment with Duritan ® PoreSurfacer DT-PS is necessary. We urgently recommend this to be used for efficientworking. Despite this, if pores or pores remaining after filling should be closed withDuritan ® Filling Primer, the filling primer can be thinned with approx. 5% PUR ThinnerS9004 (calculated on the basis of the uncured quantity of the master coat DT-F). Thecross-linking of the pores is facilitated as a result. Individual and tough spots may betrickled using a needle or a pipette. Please note that open spots caused by pores orveneer blows must be filled up. If this is not done, the problem with tough cavities orholes recurs in the next coating layer.If the substrate is finally prepared well, that is, treated with Duritan ® Filling Primer DT-F and optionally with Duritan ® Pore Surfacer DT-PS several times, you can apply thetopcoat. The last sanding prior to the use of a topcoat should be done with a grainsize of P320 for the subsequent use of Duritan ® , and in case of recoating with otherZweihorn ® varnishes with a grain size of P320 to P400.High-gloss Deep mat Silky glossDT-HG or CL-H DT-TM Crystallit ® or DuocrylDT-F optional DT-F optional DT-F optionalDT-F DT-F DT-FDT-F DT-F DT-Foptional DT-F thin (60µm) + DT-PSoptional DT-F thin (60 µm)+ DT-PSCoarsely porous wood (even exotic ones)optional DT-F thin (60 µm) +DT-PSWe have taken the trouble to present realistic compositions and have also includedthe optional steps. Please note that the number of the coating layers may varydepending on the property of the substrate and the type of wood.Tip: It is recommended to first wash woods that are very rich in ingredients such as,for example, exotic varieties like Teak or Wenge using the Zweihorn ® UniversalCleanser and to insulate it with a coating of Diadur ® Filling Primer DD-F.41

Coloured paint compositions on raw MDFOur recommendations:High-gloss Deep mat Silky glossDT-HG or CL-H DT-TM Crystallit ® or DuocrylWNC/colour WNC/colour WNC/colourWIG-IF or WIG/FILL WIG-IF or WIG/FILL WIG-IF or WIG/FILLDT-F DT-F DT-FDT-F thin DT-F thin DT-F thinRaw MDFColoured paint compositions on coated substrate (foil)Our recommendations:High-gloss Deep mat Silky glossDT-HG or CL-H DT-TM Crystallit ® or DuocrylWNC/colour WNC/colour WNC/colouroptional* WIG-IF orWIG/FILLoptional* WIG-IF orWIG/FILLKS foil, primer foil, HPL (always sanded)optional* WIG-IF orWIG/FILL* = with certain foils, you can dispense with the WIG-IF or WIG-FILL (please check theadhesion in advance and sand the foil with grain size of 320!).Attention: Please note the correct colour paint system given in following pages for theZweihorn ® system!42

The coloured paint systemThe coloured paint system is applied as described in the table previously. In theprocess, special attention needs to be paid to the interaction between Wigranit ®Novacolor and Duritan ® High-Gloss Varnish DT-HG.After applying WNC/colour on the sanded substrate, you must apply the topcoat after 2to maximum 6 hours using Duritan ® High-Gloss Varnish DT-HG.Reason:In the early drying stage of Wigranit ® Novacolor, the chemical cross-linking of the paintand hardener commences, as a matter of fact, but however, the film is still soluble, sothat a chemical compound may occur between the layers of coating. If the drying timeof the WNC/colour is increased, for example, overnight, the coloured paint surface canno longer be dissolved.Attention:These recoating times must necessarily be complied with in order to rule out anyadhesion problems subsequently.Similarly, proper hardening of Wigranit ® Novacolor WNC/colour is also a prerequisiteaccording to the technical data sheet.43

SandingDuritan ® becomes hard very quickly andhence, it can also be sanded very earlyafter coating and with more coarsesandpaper.45

The sandingIn order to be able to sand Duritan ®properly, a coating film that has hardenedwell is a basic prerequisite. In contrast toconventional PUR coating systems,Duritan ® film of varnish appears the samewhen it is hardened or not. Checking this ispossible with the finger only if it is donecarefully.The curing of Duritan ® may be adverselyaffected by the following parameters:• too little or no activator• very dark substrate• chemically treated substrates(hydrogen peroxide, ammonia, etc.)• very large distance from the exposuredevice• too early or too short exposure(see the minimum times on page 35)• shadow and semi-shadow zones• grooves and milled profiles or sectionsthat cause shadows• contaminated Perspex sheet in theexposure panel• contaminated reflectors• defective or used lamp tubesSanding with the eccentric sander (stroke max. 3 mm)Sanding the coating on the edges manuallyAfter ensuring that the substrates coatedwith Duritan ® have been properly exposedand the drying times have been compliedwith, the objects can be sanded.46

For intermediate sanding in the systemusing Duritan ® Pore Surfacer DT-PS aswell as Duritan ® Filling Primer DT-F werecommend grain size of P 240.Exception: If there is a risk of sandingthrough stained surfaces, we recommendthat you apply a primer coat of Duritan ®Filling Primer DT-F to the stained surfacebefore filling it, or apply a coat of the fillerDuritan ® Filling Primer DT-F without lightexposure.Please note and follow the instructionsgiven in the section on "Filling" startingfrom page 27!Sanding with the automatic grinding machineIf the substrate has been filled adequately,a graded sanding P240, P320 isrecommended for the intermediate sandingof the last coat (prior to the final coat) forapplying the topcoat using Duritan ® High-Gloss Varnish, and up to P400 for thetopcoat with other Zweihorn ® varnishes.This prevents any signs of sanding to bevisible in the last topcoat.Sanding the coating on the edges manually47

PolishingDuritan ® High-Gloss Varnish has a highlevel of transparency and extreme gloss.With the Zweihorn ® Sanding andPolishing Pastes you achieve this highdegree of gloss once again aftersanding in the least time.49

Five steps to the perfect high-gloss surfacewith Duritan ® Three-Pack High Solid High-Gloss Varnish DT-HGIn order to be able to achieve a high-classhigh-gloss surface, the coating system must beapplied carefully and, as far as possible, in adust-free environment. The individual layers ofcoating should dry at least overnight in order tominimise subsequent dropping!1. Applying a primer coat with Duritan ®Two-Pack Pore Surfacer and / or Three-Pack High Solid Filling Primer DT-FIn case of coarsely porous or highly absorbentwoods, we recommend the use of Duritan ®Pore Surfacer. This transparent filler is solventfreeand fills the pores in 1-2 passes (see thetechnical data sheet). In this manner, you saveseveral passes and thus, time and money.Duritan ® Filling Primer DT-F has extreme fillingpower, is highly transparent and is applied afterfilling the pores with Duritan ® Pore Surfacer ordirectly on the raw wood (see the technicaldata sheet). Depending on the need andsubstrate, DT-F is applied several times. Atleast one overnight drying is recommendedbetween the individual applications of the coat,since this considerably improves the non-sagproperties. No special pre-treatment isnecessary in case of MDF for use in wet orhumid rooms.If the surface needs to be coated withWigranit ® Novacolor WNC/colour prior toapplying the high-gloss coat, it must first begiven a primer coat of Wigranit ® Two-PackMDF Insulating Filler IF or Two-Pack PURFiller WIG/FILL.50

2. Coating with Duritan ® Three-PackHigh Solid High-Gloss Varnish DT-HGApply the coat of Duritan ® High-GlossVarnish according to the technical datasheet after allowing the well preparedsurface to dry overnight.Since Duritan ® High-Gloss Varnish hasapprox. 80% of solids, a one-timeapplication prior to polishing is sufficient. Athree-pass system as in the case ofconventional high-gloss varnishes is notnecessary, since adequate dry film layer isavailable for sanding and polishing.3. Preparation for polishingAfter a curing time of 1-3 days, you can doboth dry and wet sanding.What is important with dry sanding is anexcellent eccentric sander havingoutstanding dust extraction feature and thegenerous use of fresh sandpaper (grainsize 1,500 - 2,000).Using wet sanding techniques, however,with Duritan ® you achieve the final resultfaster.By using 800 grain size sandpaper for thefirst plane sanding, you achieve sandingtimes with extremely hard Duritan ® High-Gloss Varnish that are comparable withthose for conventional high-glossvarnishes.The subsequent sanding steps should bedone using 1,000 and 3,000 grain size wetsandpaper. We recommend that you stripthe surface with a window wiper to controlthe sanding result with wet sanding.You can begin with polishing if the surfaceis completely matt.When processing the entire surface, neversand manually!51

4. Polishing with High-Gloss GrindingPaste HSPApply the High-Gloss Grinding Paste HSP,at any spots on the coated surface.The consumption is based on the surfaceproperty and the machine type.By spraying on some tap water, thesurface can be cooled down during thepolishing process and the High-GlossGrinding Paste can be somewhat thinned.You can differentiate between twoprocessing techniques:Polishing by hand with the angle polishingmachines:By using lambskin pads, the distribution ofthe special High-Gloss Grinding PasteHSP yields the initial gloss with therequired pressure and uniform to and fromovements.Attention: Do not polish too long on oneside, since the coating can become veryhot and, under certain circumstances, theveneer comes up or the surface becomesblind! If the surface is too dry, paste mustbe added again since, otherwise, thesurface becomes too hot.Tip: Check the heating on the surface withthe back of your hand. The surface shouldonly be lukewarm!52

Polishing on tape machines or automaticflap-wheel machinery:Apply the High-Gloss Grinding Paste HSPto the surface to be treated or in case ofautomatic flap-wheel machines, spread itin front of the polishing cylinder.Spreading and polishing takes placeautomatically with the help of felt / tuft beltsor polishing cylinders.Tip: The felt tape should always be keptmoist so that the surface does not becometoo hot! Simply spray water on the felt tapeusing a spray bottle.You can achieve 96% of the desired glossusing the High-Gloss Grinding Paste HSP.This is often sufficient for the requirementsof many customers.For high-class and high-gloss surfaces,however, we recommend that you carryout step 5. This brings the final gloss sothat you cannot detect the difference froman unpolished surface any longer with thenaked eye.However, please note that you use themaximum polishing time for the High-GlossGrinding Paste HSP, since it is moreabrasive and thus, polishes off even themost minor scratches.Please make sure to read the separatetechnical data sheet of the High-GlossGrinding Paste HSP!53

5. Polishing with High-Gloss PolishingPaste HPPApply the High-Gloss Polishing Paste HPPat any spots on the coated surface.The consumption is based on the surfaceproperty and the machine type. Byspraying on some tap water, the surfacecan be cooled down during the polishingprocess and the high-gloss polishing pastecan be somewhat thinned.You can differentiate between twoprocessing techniques:Polishing by hand with the angle polishingmachines:The special High-Gloss Polishing PasteHPP is spread on the surface to bepolished with a honeycomb sponge pad(orange) with the required pressure anduniform to and fro movements.If the surface becomes too dry, paste mustbe added again since, otherwise, thesurface becomes too hot.Using the High-Gloss Polishing Paste, youcan almost achieve the gloss of anunpolished high-gloss surface.Nonetheless, only when you sand thesurface well and pre-polish it with the HSP.54

Polishing on tape machines or automaticflap-wheel machinery:Apply the High-Gloss Polishing Paste HPP tothe surface to be treated or in case ofautomatic flap-wheel machines, spread it infront of the polishing cylinder. Spreading andpolishing takes place automatically with thehelp of felt / tuft belts or polishing cylinders.Please make sure to read the separatetechnical data sheet of the High-GlossPolishing Paste HPP P!Cleaning the ready polished surfaceIn order to clean the surface from the polishresidues, simply wipe it with a micro-fibrecloth or apply small quantities of the High-Gloss Polish 10099, on the surface.It not only removes any residues of the High-Gloss Polishing Paste HPP that are present,but achieves still more brilliant surfaces. Afterdrying the surface, wipe it with a polishingsponge until it appears crystal clear.Subsequent polishing with the High-GlossCare Product HGP is possible (Caution:contains silicone!). As a result, the surfacebecomes insensitive to scratches.Brief overview of the polishing steps1. The basic wet sanding with minimum P800 (Mirka Polarstar or 3M 260L nonperforated)2. Wet sand-polishing P1200 Mirka Polarstar or P1000 3M Trizact3. Wet sand-polishing P2000 Mirka Polarstar or P3000 3M Trizact4. Wet sand-polishing P4000 Mirka Abralon (omitted with 3M)5. Polishing step Zweihorn ® High-Gloss Grinding Paste HSP with lambskin6. optional polishing step Zweihorn ® High-Gloss Polishing Paste HPP withhoneycomb pad7. Optional Zweihorn ® High-Gloss Polish 10099 with a soft honeycomb pad8. Optional Zweihorn ® High-Gloss Care Product HGP with a suitable cloth55

SectionOccupational safety /SafetyDuritan ® requires, like all varnishes,special attention to be paid to the safetyof the employees who process theseproducts day after day.Respiratory protection from page 60Skin and hair protection from page 64Protection against radiation from page 67Explosion protection from page 7157

Respiratory protectionDuritan ® products have little or nosolvents. Despite this or particularly thisis why the persons work with it mustwear breathing apparatus.59

Coating workA word on respiratory protection at thisjuncture.Unfortunately, there is still a widespreadbelief that no respiratory protection isrequired when coating wood:"…the extraction is good enough…" ,"…that is what we have always done…".In Duritan ® just as in other PUR coatingsystems, a high quantity of hardeners(Isocyanate hardeners) is sprayed apartfrom solvents and thus get into the air asaerosol and hence, find their wayinevitably into the lungs of those applyingthe coat, if no respiratory protection isused.Never paint without breathing apparatus!The extraction is NEVER (!) adequate inorder to protect the painter from this riskand hazard. In case of 3-dimensional partsor a body from inside, everyone hasdefinitely experienced this on their ownsome time or the other.While in painting in the automotiveindustry, each painter knows about thisand works accordingly, the timber industry,unfortunately, is still somewhat in thestages of infancy. Protecting the fingerswhile milling is something that you seedaily, but while painting, however, youoften tend to be negligent or careless.Spray mist contains, among others, solvents,hardeners and binding agentsIt is for this reason that the recommendationcan only be: Always wearbreathing apparatus.60

This means that if you are doing paintingwork daily for less than 30 minutes, youcan fall back on a half mask with a filter,e.g., type A2P2.The filters must be replaced regularly, e.g.,every 2 weeks and ideally, these must bedocumented in a filter replacement list foreach employee.Yet another note here: The masks mustalways be kept in safe custody outside thepainting and application rooms (at best, inclosed containers), in order to ensureflawless working of the active carbon filter.Half mask for < 30 min. of painting work per day!For more detailed information pleasecontact the relevant manufacturers ofbreathing masks and apparatus such as,for example, MSA, Sata, 3M etc.When working for more than 30 minutesper day, it is necessary to use ventilatedmasks (with external air supply).Mask systems independent of thecirculating air are suitable for this purpose,e.g. from Sata or 3M with an air hosepipeor systems that depend on the aircirculation having filters and fans driven offrechargeable batteries.The advantage of the systems ventilatedwith fresh air (independent of circulationair) lies in the long term, e.g., with thecosts that filter replacement is avoided inthis case. Moreover, when doing paintingwork for longer periods, breathing isconsiderably easier as compared with halfmasks.Full mask for > 30 min. of painting work per day!61

Skin and hair protectionThe spray mist of Duritan ® settles, justas in the case of other varnishes, on theskin and hair and cures only with theincidence of sunlight.This is why you need to protect the skinand hair accordingly.63

Skin and hair protectionSkin and hair protection is also importantapart from respiratory protection.Just as with all paints, even with Duritan ® ,protective gloves (at best, disposableLatex gloves) should be worn.The advantage of disposable gloves lies inthe fact that, as a result of the lower costs,the single use and immediate replacementin case of contamination takes place fasterthan with expensive, non-disposablegloves. Latex gloves are available invarious qualities. With increasedprotection, however, the price alsoincreases, and the wrong presumption thatthese can be reused or worn for a verylong time. Nonetheless, gloves alwaysoffer only resistance times againstcontamination that vary, that is, once theyare contaminated, it is a matter of qualityvs. time before the material startspenetrating. Hence, the right approachhere is to replaced them more often andmore quickly.Basically, the body must be protectedacross the entire surface from paint dust /droplets. Apart from gloves, it is alsorecommended to use overalls, electrostaticdischarging safety shoes, safety gogglesand, if required, hair protection.When painting for longer periods, it isrecommended, particularly while workingwith Duritan ® , to use a disposable overall,since paint particles settle on the clothingand these then get cured subsequently(e.g. with exposure to sunlight).64

The right protective gear at a glance:Ventilated full mask(driven by a rechargeable battery or bycompressed air)Disposable overall(with a head coveror hood)Disposablegloves(solvent-resistant)Safety shoes(possibly still protection for the shoes)Note: This safety gear is, incidentally, not only meaningful for Duritan ® , but alsowhen processing all other paints (including water-based paints!)!65

Protection againstradiationDuritan ® products get cured by sunlight.Even when dealing with soft UV light,you must comply with certain safetyregulations in order to protect yourselfand the other employees.67

Protection against radiationWhen UV radiation is being used, youmust apply yourself to the subject ofprotection against radiation. Highlytechnical details are omitted here in orderto keep this section as clear and vivid aspossible.Background:With UV radiation, you differentiate, on theone hand, between intensity (i.e., thestrength of the incident radiation) and theenergy or wavelength of the radiation. Thelatter is differentiated in UV-A, B, and C.The UV-A rays (400-320 nm) are the leastharmful in this range and are also radiatedby the sun on the Earth similar to the UV-Brays (320-280 nm).UV-C rays that are rich in high-energy(280-200 nm) are, in fact, also emitted bythe sun, but prevented from reaching theEarth by the protective layer of ozone.Duritan Hand lampDuritan Belichtungsfeld68

Duritan ® hand-held lampThe hand-held lamp is a "classical" UVemitter (mercury lamp) with relatively highpower (about 80 -100 mW/cm²) andradiation intensity (280-350 nm). Even if itdoes not come close to the power levels ofstationary UV emitters by a long shot(which lie in the range of 80,000-150,000mW/cm²), nonetheless, the power outputand also the wavelength must not beignored.Since it is an emitter with an energyspectrum primarily in the UV-B range,attention must particularly be drawn herethat UV safety gear with, for example, UVproofgoggles and UV-proof clothing mustbe worn.The illumination must always be orientedaway from your body and should never bepointed at other persons.Duritan ® exposure panelIn contrast to the hand-held lamp, theexposure panel is to be considered lesscritical. The radiation dosage here ismaximum only 10-15 mW/cm² measureddirectly at the surface of the device andfalls rapidly to below 1 mW/cm² if youmeasure it at a distance of 1 m away fromthe tubes.For comparison: The radiation intensity ofthe sun behind a double glazing window is,for example, up to 2-3 mW/cm² in spring.Stated clearly once more: The exposurepanel is an extremely weak emitter, which,at a distance of 1 m is less critical than thesun behind windows.69

Explosion protectionDuritan ® products have little or nosolvents.It is for this reason that by complyingwith certain parameters, Duritan ® lightexposure devices can also be used inexplosion-prone zones.71

Explosion protectionUV emitters or exposure devices are notavailable in explosion-proof design.The explosion-proof designs cannot berealised both on cost and constructiveconsiderations (similar to the infra-reddrying equipment).On the other hand, explosion-prone areasmust almost always be specified inpainting booths (cabins) and divided intozones (see, for example, BGI 740).It is for this reason that the explosionprotection must be ensured with the helpof other technical and organisationalmeasures.In cooperation with (Graduate Engineer)Mr. Roland Knopp of the professionalassociation, Metall Nord Süd, who isgenerally in charge of the technicalcommittee, "Metal and surface treatmentfor painting plants", the subject ofexplosion protection with the Zweihorn ®Duritan ® exposure systems wasinvestigated.Outcome:Under certain conditions, which aredescribed and illustrated in the followingpages, the Duritan ® light exposure devicescan also be used in explosion-prone areas.Note: The following requirements arealigned with section 3.1.2 of the BGR 500,section 2.29 "Processing of coatingmaterials".72

1. Light exposure in the spray booth(cabin)The desire to expose objects to lightimmediately after coating can be doneunder the following conditions:a) The technical ventilation has been checkedand causes assured extraction of thesolvent vapours so that any explosiveatmosphere is prevented to themaximum extent. (The paint booth orcabin is, in contrast to the widespreadopinion, often less critical than, forexample, a hermetically sealed dryingroom).b) You should not apply the coating under anycircumstances when using the exposurepanel / hand-held lamp.c) Between the coating and exposure, youmust allow ample time with the extractionswitched on (e.g. at least 10 minutesdrying time).d) An interlock must be provided forinadvertent exposure when the coating isin progress (a so-called blockingprotective mechanism, in which, forexample, the socket is not live withactive compressed air)e) During the coating process, the exposurepanel and the hand-held lamp must beremoved from the coating area orprotected against paint aerosols andsolvent vapours effectively.In particular, the points b), c) and e) must beincluded in the Operating Manual.73

2. Exposure in drying rooms that are joined with the spray booth or cabinThe same applies here as given under paragraph 1.In addition, it is recommended to install an additional floor extraction system here nearthe rack trolley.Note: The extraction should always be done near the floor (not above the rack trolley)since the solvent vapours are heavier than air and fall to the ground.Exhaust airFloor extractionDrying roomExhaust airSpray wallAir supplySpray room74

3. Exposure in separate drying roomsAmong others, you must ensure here that the rooms have an exhaust air system.As far as floor extraction goes, the same applies here as given under 2.Exhaust airFloor extractionAir supplyDrying roomExhaust airSpray wallAir supplySpray room75

Preventing faultsDuritan ® is a completely newcoating system!It is but natural that faults and flaws cropup during processing. This sectionpresents the causes and the measuresfor rectifying or preventing them!77

The most important things that must definitely be taken note of and followed to preventfaults and flaws:• Do not mix the varnish in direct sunlight or UV light.• Do not work, paint or dry in sunlight or UV light.• Comply with the quantity of activator under all circumstances.• Do not use any thinners of other manufacturers.• Clean the coating devices with Zweihorn ® Universal Cleanser UR.• First rinse coating devices that contain residues of other cleaners withZweihorn ® Universal Cleanser UR.• Use only Zweihorn ® PUR Thinner S9004 for dilution or thinning.• Never mix other substances such as, for example, CK, WNC etc. in the coatingmaterial.• Comply with all parameters such as pressure, angle, clearance, nozzle size etc., seesection "Spray devices" (starting from page 9).• Make sure to provide proper exposure and lighting.• All time specifications such as the exposure time and drying time are minimum times,that is, they may always be exceeded and should not be undershot.• Always ensure that your wear the right work clothing and breathing masks.78

Fault / Flaw Cause Remedial actionThe varnish mixture appearsmore yellow than normalThe varnish gets cured in ashort time in the cupThe primer coat of Duritan ®Filling Primer DT-F appearshighly uneven. Smoothsanding takes a very longtime (see page 40).Uniformly sandy surfacesoccur while applying thevarnish. The first layerappears normal initially andthe subsequent coats areworse (see page 35).The drying is differentdepending on the substratewith the same varnishmixture.Quantity of activator addedis too highThe varnish is activated byUV light (Sunlight orscattered or stray light fromthe exposure panel / handheldlamp)The coating container wascontaminated or not cleanThe wrong thinner has beenaddedThe coating materialpenetrates non-uniformlydepending on the absorptionbehaviour of the substrateresulting in clusters beingformed.The coating materialdroplets are too large andtrap air along on thesurface.Dark substrates absorb theUV light more than the light(reflecting) substratesUse a suitable weighingmachine or dosage aid forthe activator (see pages 23-25). Use a new varnishmixture.Do not mix the varnish indirect sunlight / UV light.Use a black cup or acontainer opaque to light(see pages 23-25).First rinse all workingdevices with Zweihorn ®Universal Cleanser UR.Use only Zweihorn ® PURThinner S9004 for thinning,and for cleaning, Zweihorn ®Universal Cleanser UR.Apply a thin layer of the 1 stcoat in absorbentsubstrates, approx. 50 – 60µm, and then continueprocessing as usual.Check the followingparameters: Air pressure,nozzle size, spray angle,distance to the object, angleof the gun to the object,quantity of thinner added,quantity of activator added(see pages 33-37).Increase the exposure time.79

Fault / Flaw Cause Remedial actionThe varnish film does notcure despite properexposure.The varnish does not flowinto the wood poresAll objects that have beenmoistened in the coatingroom with Duritan ® havebecome tacky. Even thefloor is tacky.Coloured paint surfaces topcoated with Duritan ® havedifferent colours. Somecomponents appear lighterthan the othersYou have forgotten theactivatorIncorrect dosage of theactivatorThe wood has been pretreated,for example, it hasbeen bleached or treatedwith the stain (picklingagent) of anothermanufacturer.Surfaces stained withZweihorn ® Antique-FinishStain S9800/colour.Tough and sharp-edgedpores in various woods.(Mahogany, Zebrano,Wenge, Bubinga, etc.)Duritan ® cures only afteractivation.Certain components havebeen exposed too early as aresult of which the microfoam(air) could not escape.As a consequence, thecolour appears lighter andwhiter.Prepare the right varnishmixture.Prepare the right varnishmixture.Wash off bleached woodprior to coating with Duritan ®Universalreiniger (Universalcleaner) UR. Use stains(pickling agents) of theZweihorn ® brand.Allow Antique-Finish Stainto dry overnight beforecoating with Duritan ® anddouble the exposure time.Use Duritan ® Pore SurfacerDT-PS (see pages 27-31and pages 39-43). You canwork in the coating materialusing a coating knife orbrush, or fill up the individualpores using a pipette orneedle.Spray all tacky objects withDuritan ® Overspray DrierDT-OT, which causes cureswithin a few minutes.Comply with the drying orsettling time at all costs andavoid inadvertent prematurecuring by the incidence ofsunlight or scattered or straylight from the exposurepanel.80

Fault / Flaw Cause Remedial actionThe last layer of varnish withDuritan ® High-Gloss VarnishDT-HG showed spots on thesurface on account of whichpolishing seems necessary.You can notice streaks andfinger prints in the highglosssurface that iscompleted.During the rest time ofDuritan ® the film of varnishis still "open". Thus, duringthis period, dust particlescan fall on the varnish filmand cause spots to beformed on the high-glosssurface.If prior to the application ofthe topcoat with Duritan ®High-Gloss Varnish DT-HG,traces of Duritan ® residueswere present on the fingersor clothes applied on thesurface, these can stand outsubsequently. This canoccur by over-spray or bywet cleaning using a clothcontaminated with Duritan ®Universal Cleanser UR. Thisis visible particularly on darksubstratesDust particles falling on thesurface within the rest timecannot be prevented, buthowever, it can be reducedconsiderably: Provide a lowdustworking environment(e.g., humidify the spray /drying room in advance!).Avoid transporting theobjects as far as possibleafter coating them. Avoidraising or stirring up dust, forexample, by movements ofthe exposure panel. If theenvironment does not permitlow-dust coating, it ispossible, as an option, toapply a coating withDuritan ® Filling Primer DT-Fand to use Crystallit ® High-Gloss Varnish CL-H as thetopcoat.Avoid touching the surfacesafter they have been givenintermediate sanding. Donot touch the componentswith tacky Duritan ® fingers.Carry out only dry cleaningusing a tack cloth. Do notallow the cloth to lie openlyafter use.81

Fault / Flaw Cause Remedial actionObjects are tacky on thebottom side owing toover-spray.Duritan ® varnish film canbe removed completelyfrom the substrateWigranit ® NovacolorWNC/colour like a foil.The high-gloss surfaceshows slight unevenness(Orange skin)The surface appears tobe milky / smoky.82Duritan ® cures after activation.Shadow regions requireconsiderably more time forcuring.The Duritan ® film pulled out istransparent:WNC was, in fact, processedcorrectly, but however, topcoated with Duritan ® too late.The Duritan ® film pulled out iscoloured:Composition of Duritan ® withWigranit ® Novacolor has, infact, taken place, but however,the coloured coat is unstable.Either the check for adhesionwas done too early, as a resultof which WNC was notadequately cross-linked, orWNC was processed withouthardening it inadvertently.You have not complied with thefilm thickness and / or the gunclearance.Film thickness is too high and /or too much activator addedand / or too much thinner addedand / or object exposed toosoon.Place objects / componentsonly on the pipe of the racktrolley and place the rearmirror at an angle tofacilitate exposure of thebottom side. Similarly, whenusing the hand-held lamp,expose the object frombelow.Improperly coated objectscan be repaired only bycomplete removal of theDuritan ® varnish filmfollowed by the applicationof a new coating material.For this purpose, removepoorly adhesive Duritan ®layers of coatingmechanically, and finallysand the coloured coatthoroughly. Apply a freshcoat of Wigranit ® NovacolorWNC and put a topcoatwithin the time specifiedusing Duritan ® High-GlossVarnish DT-HG or Duritan ®Deep-Mat Varnish DT-TM.Check the film thickness aswell as the gun settings andadjustments.If required, increase thedrying or settling time priorto exposure.Dilute the coating materialusing PUR Thinner S9004.Observe the maximumquantity to be added in theprocess (see page 25).Check the coating mixture,avoid extreme individuallayers and preferably useseveral layers of coating.Observe and follow thedrying or settling times.

FAQ (Frequently Asked Questions)I have forgotten to apply a topcoat of Duritan ® within the specified time frame toWigranit ® Novacolor. How must I now proceed?Sand the substrate with grain size 320 and apply a new coat of Wigranit ® Novacolor.Next, the surface must be top coated within a time span of 2-6 hours with Duritan ®without sanding it again.The tubes of both components of Duritan ® Pore Surfacer cannot be opened afterhaving used them once.Please take care to ensure that no filler material comes on the threads, that thecontents of the tubes are not exposed to light (close the tubes again!) and that the tubecaps are not exchanged (mark the cap with an Edding highlighter!).I have forgotten to add the DA2 activator and coated my object. Can I somehowcure the surfaces or do I have to wash away everything completely?If there is no activator in the mixture, it cannot be added subsequently or recoated onthe surface. A new topcoat of a varnish / activator or paint / thinner mixture cannot berecommended since inexact and uncontrolled mixtures occur. The safest method,hence, is to remove the non-activated film of coating mechanically (rubber coating knifeand / or clean cloth with the help of Zweihorn ® Universal Cleanser UR.Can I cure Duritan ® in the sunlight?In general, yes! The light exposure times, however, are different as a result of varyingintensity of the sun's UV rays. Hence, for professional use with consistent curing times,we always recommend the Duritan ® exposure panel or the Duritan ® hand-held lamp.My coating and drying room is thoroughly flooded with sunlight. Could there bedamage resulting from this?Yes! After coating with Duritan ® , a certain rest period must be maintained prior to lightexposure. If the coating or drying room is intensely flooded with sunlight, prematurelight exposure takes place after applying the coat. This has the consequence that themicro-foam (air) cannot escape from the surface and, as a result, the surfaces appearmilky and turbid. In the case of surfaces that have been top coated with bright colours,different colour shades can occur as a result. Hence, please darken the coating ordrying room.83

FAQ (Frequently Asked Questions)Is the Duritan ® Overspray Drier suitable for activating coated surfaces? Couldthis be an alternative to the exposure panel?No, the Duritan ® Overspray Drier is a watery product that is not compatible withDuritan ® varnishes. It only ensures curing of the over-spray.I have inadvertently used a washing thinner of another manufacturer to clean myspraying gun after using Duritan ® .You are lucky if immediate curing has not taken place. However, please consider thatrecycled thinners particularly, e.g., washing thinners, can vary depending on the batch.Should another thinner work as specified, it is no guarantee that the same brand ofthinner will work always. Hence, for thorough cleaning without any surprises, wealways recommend Zweihorn ® Universal Cleanser UR. If immediate curing has takenplace, you must promptly try to clean the gun mechanically or with a stain.I do not have the nozzle required at hand. Can I use another nozzle?Duritan ® is a new coating system that assumes the availability of optimal equipment.Please use the nozzle sizes specified and comply with all parameters asrecommended in order to the get perfect results. If you would only like to try out thesystem, you can reduce the material quantity by adjusting the needle. However, in thelong term, you should definitely procure the right equipment.I would like to use my air mix system for coating with Duritan ® in order to beable to work economically and efficiently.Airmix systems compress the coating material with the ratio specified on the pump. If,for example, a ratio of 1:28 is specified, the coating material is compressed to 28 barwith an inlet air pressure of 1 bar. As a result of this high pressure, air is mixed whilecoating in the Duritan ® coating mixture and it cannot escape from the film of coat. Theresult is that the surfaces become sandy, spotty and milky. For economical andefficient working, you have the option of using a coating systems that does notcompress the coating material (1:1 ratio). We recommend, for example, the Sata VarioTop Spray (see page 11).84

FAQ (Frequently Asked Questions)I would like to repair minor coating flaws with Duritan ® at site. Is this possible?Yes, however, it is recommended not to apply a coat using the spray gun at site. Minorcoating flaws can be touched up with a brush and exposed to light with the Duritan ®hand-held lamp.I do not have any recommended UV RPS cup of SATA at hand, what then?If no direct sunlight or scattered light from the exposure panel or from the hand-heldlamp falls on the coat, Duritan ® can also be mixed and processed in transparent cups.Similarly, larger coating quantities can also be used in opaque containers, e.g., metalliccans.I have forgotten to clean my spray gun after using it with Duritan ® , and thevarnish residues can no longer be loosened with Zweihorn ® Universal Cleanser.Can the gun be salvaged?Please try to clean the gun with a special gun cleaner (paint remover).I have forgotten to switch off the exposure panel. As a result, the objects havebeen inadvertently exposed for a very long time. Does this damage the film ofpaint? Can it possibly become spotted or fade?Any overexposure of the Duritan ® varnish films does not have any impairing effect onthe coated surface. After curing has taken place, the coating system is no longeractive, i.e., it cannot get spotty or brittle. Duritan ® is lightproof, and hence, the varnishfilm also does not fade or get discoloured. We could not find any instance of fading ordiscolouration in tests conducted by us (8 hours of continuous exposure) even tointense woods sensitive to UV light such as maple or cherry wood.Do I have to insulate (e.g. with Plastic Varnish S 7000) exotic or other woods richin ingredients prior to coating them with Duritan ® ?No! Duritan ® is a highly insulating coating system. It is not necessary to apply anyspecial insulating primer and this is also not recommended. Woods that are rich iningredients, or feel greasy or oily, such as, for example, pine or teak, should bewashed off with Zweihorn ® Universal Cleanser UR prior to coating with Duritan ® . Forthis purpose, the product is applied to clean, non-fluffy cloth balls and the wood degreasedin the grain direction.85

Akzo Nobel Deco GmbHZweihorn DivisionDüsseldorfer Strasse 96-10040721 Hilden / GERMANYTelephone: +49 (0) 2103 / 77-800Fax: +49 (0) 2103 / 77-242www.zweihorn.comE-mail: zweihorn@zweihorn.com