1 Troubleshooting Guide Solutions to Common Finishing Problems 2 Adhesion Inter
1 Troubleshooting Guide Solutions to Common Finishing Problems 2 Adhesion Intercoat Stain Substrate Air Entrapment Bénard Cells Bleeding Blocking Blooming Blushing Brittleness Brown Spots Bumps and Sinks Cold Check Cratering Crawling Discoloration Dry Fat Edges and Picture Framing Fish Eyes Floating Flooding Gloss Variation Grey Pores Haze Hiding Lifting Contents Page 4 Page 5 Page 5 Page 5 Page 6 Page 6 Page 6 Page 7 Page 7 Page 7 Page 7 Page 8 Page 8 Page 8 Page 9 Page 9 Page 9 Page 10 Page 10 Page 10 Page 11 Page 11 Page 11 Page 12 3 Marring Mud Cracking Orange Peel Printing Rub Up Sagging Seeds Separation Silking Skinning Solvent Popping Solvent Trap Tearing Telegraphing White Spots Contents Page 12 Page 12 Page 13 Page 13 Page 13 Page 14 Page 14 Page 14 Page 15 Page 15 Page 15 Page 16 Page 16 Page 16 Page 16 4 Adhesion – Intercoat Problem Delamination between coats Whitening of fi lm between coats Solution Ensure correct sanding between coats Topcoat within recommended time limit after sanding Allow correct dry time of sealer coats Use correct fi nishing system Ensure no contamination on previous coat Apply a wet coat material Do not fog or mist coating to apply thinner fi lm builds Adhesion – Stain Problem Delamination to stain Whitening of fi lm between coats Solution Reduce application of stain Ensure suffi cient wiping of stain Allow correct dry time of stain Dark stains should be obtained by using toners before stain application Avoid heavy shading Make sure to use the correct fi nishing system (sealer/topcoat) to match stain. Apply wet coat of sealer or topcoat Do not fog or mist coating to apply thinner fi lm builds Adhesion - Substrate Problem Removal of fi lm to substrate Delamination to substrate when impacted Solution Ensure correct sanding of substrate Use correct fi nishing system to match topcoat with primer used Ensure no contamination on substrate Apply wet coat of material Do not fog or mist coating to apply thinner fi lm builds Closed grain hardwoods should be well sanded before use Higher solids fi nishes need a better wood profi le to anchor to than low solids Ensure sand paper is not worn 5 Air Entrapment Problem Bubbles from pores in the wood Air entrapment from preparation of paint Air entrapment from application Blistering from drying techniques Topcoat attacking previous coat Solution Use defoamer Use slower solvent balance Change airfl ow during drying, check for drafts Reduce air pressure during application Spray thin wash coat as fi rst coat Ensure adequate fl ash off before oven Reduce viscosity Bring lacquer to room temperature Use correct thinner Use weakest solvent for previous coat to avoid blistering Reduce recirculation speed Reduce fi lm thickness Bénard Cells Problem Cell pattern in fi nish Color and surface irregularities Solution Add dispersant Add silicone additive to reduce surface tension Increase application viscosity Lower application thickness Add thixotrope or thickener Bleeding Problem Color migration from coated substrate Color in sanding dust Colored fi lm on surface Solution Avoid bleeding dyes and pigments Use vinyl sealer to seal color Change from acid catalyzed material 6 Blocking Problem Sticking together of panels when dry Solution Reduce fi lm build applied Increase or ensure recommended dry times are followed Ensure ovens are at the correct temperature Increase or ensure correct airfl ow during dry Ensure correct temperature of substrate Decrease or ensure correct temperatures at stacking Blooming Problem Hazy deposit on fi lm Oily or wax-like substance on surface Reduced gloss Mottled or non-uniform surface Solution Adjust catalyst level – over–catalyzation Do not use stearated materials such as lacquers and certain polyesters under acid catalyzed coatings Check formula for incompatibility Check substrate for contamination Blushing Problem Whitening of surface Lowering of gloss Solution Reduce humidity Use richer thinner Check water level in equipment Warm lacquer to room temperature Increase temperature of application area Slow dry time Dry waterborne stains or sealers 7 Brittleness Problem Poor coin scratch Delamination of fi lm when impacted Solution Ensure that brittleness is not lack of adhesion Check with representative If a catalyzed system, check ratio Brown Spots Problem Brown spots in fi lm Solution Clean air lines of oil contamination Drain or repair oil separator Bumps and Sinks Problem Uneven surface appearance LOW Depth of Image (D.O.I.) Solution Add silicone fl ow additive Add thixotrope Cold Check Problem Cracks in fi nish Solution Decrease dry fi lm build Ensure minimum room temperature during cure Use only freshly catalyzed material Ensure correct catalyzation Ensure profi les are sanded to reduce sharp angles 8 Cratering Problem Depressions in fi nish with raised edges and material at center Solution Remove source of contamination Clean substrate before application Clean equipment before application Filter material Clean air system and ventilation control Addition of silicone fl ow agent Crawling Problem Formation of beads, islands, craters or pinholes Poor wetting of substrate Solution Clean substrate before application Ensure sanding before application Addition of silicone fl ow agent Discoloration Problem Change in color of fi nished parts Yellowing of fi lm Solution Check age of coating Check contamination from drum liner Check iron or aluminum contamination from application equipment Check for presence of foreign vapors or fumes Check to ensure presence of UVA, if required Check to ensure material not stored at excessive heat Check for tannin bleed 9 Dry Problem Wet fi lm Soft fi lm Solution Decrease humidity during application Increase temperature in drying and curing area Clean wax or oil contamination from substrate Mix catalyst and thinner well into material Ensure correct ratio of catalyst Reduce / ensure correct addition of retarder solvent Fat Edges and Picture Framing Problem Paint build-up on edges Poor edge coverage Solution Addition of thixotrope Addition of silicone fl ow agent Faster solvent balance Lower viscosity Ensure profi les are sanded to remove sharp edges Fish Eyes Problem Depressions in fi nish with raised edges and uniform material at center Undispersed droplets in paint Solution Remove source of contamination Remove source of incompatibility Clean substrate before application Clean equipment before application Clean air system and ventilation control Addition of silicone fl ow agent 10 Floating Problem Mottled, blotchy or streaked appearance Separation and uneven distribution of pigment Result of Bénard cell formation Solution Increase application viscosity Lower application thickness Add thixotrope or thickener Add dispersant Add silicone additive to reduce surface tension Flooding Problem Uniform color change Surface enrichment of one or more pigments Different color on disturbed surface/ Rub-up Solution Reduce fi lm thickness Raise viscosity of coating Speed drying Gloss Variation Problem Uneven gloss areas Incorrect / unexpected gloss Flat or glossy spots Solution Ensure correct drying or oven temperatures Ensure correct fi lm build Apply seal coat to eliminate absorbent areas on substrate Reduce solvent strength to reduce exudation of resins from wood Ensure clean substrate Addition of silicone fl ow agent 11 Grey Pores Problem Grey areas in deep pores Poor cleaning of sanding dust from pores Poor wetting of pores Solution Blow out sanding dust from pores on sanded panels Reduce viscosity of sealer Add non-contaminating silicone to improve wetting of sealer Change sealer to improve wetting and shrink-back Change to urethane sealer Haze Problem Dulling of fi nished surface Exudation to surface Fine solvent pops Microvoids Fine Bénard cells Solution Use correct thinner Check current catalyzation Check the dry of previous coat Stir material to ensure uniform product Use retarder solvent Hiding Problem Poor coverage Show-through of dark lines at edges of profi les Solution Reduce amount of thinner in material Mix material thoroughly before use Increase / ensure correct fi lm build Sand sharp corners of profi les Increase speed of solvent balance 12 Lifting Problem Wrinkling of the fi nish Unevenness of the ripple effect on surface Solution Ensure correct system Do not use weaker fi lms under stronger Apply thinner coat of topcoat Apply heavier coat of sealer Use weaker reducer Ensure correct air movement and dry Allow longer dry on previous coat Ensure correct catalyzation Use freshly catalyzed materials Marring Problem Surface damage when scratched Solution Use freshly catalyzed material Increase dry and cure of fi nish Increase cure area to room temperature Allow 14 days to obtain full cure with acid cure materials Add silicone anti-mar additive Follow manufacturers recommended shelf life Add coalescing solvent to waterborne material to ensure good fi lm formation Mud Cracking Problem Fine cracks in surface of waterborne fi nish Solution Increase temperature of application area Increase drying temperature Add coalescing solvent under agitation Increase substrate temperature 13 Orange Peel Problem Surface bumpiness or waviness Orange peel effect Poor leveling Solution Check and / or lower viscosity Apply correct or thicker fi lm build Reduce dry spray or overspray Increase atomizing air Reduce fl uid pressure Check correct air cap Use retarder solvent or rich thinner Eliminate excessive air movement Add silicone fl ow agent Apply even stroke with spray gun at the correct distance from uploads/Geographie/ troubleshooting-guide-solutions-to-common-finishing-problems.pdf
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- Publié le Dec 07, 2022
- Catégorie Geography / Geogra...
- Langue French
- Taille du fichier 0.2323MB