Red Seal Auto Refinishing cheat sheet

Isocyanate exposure: sensitization can occur after a single overexposure; once sensitized, any further exposure can trigger asthma. Supplied-air respirators are required for spraying 2K isocyanate products in most jurisdictions; dust masks and cartridge respirators do not protect against isocyanate vapour.

Respirator fit: qualitative fit testing (saccharin, Bitrex) is acceptable for half-mask respirators; quantitative fit testing (PortaCount) is required for full-face and supplied-air units. Re-fit test annually and after facial changes such as weight change or dental work.

VOC limits: solventborne basecoat and clearcoat are regulated by VOC content (g/L minus water and exempt solvents). Compliant coatings are typically waterborne basecoat plus high-solids clearcoat; mixing compliant and non-compliant products does not change the regulated category of the resulting mix.

Flash point and fire safety: solvents with flash points below 23 °C (Class I) require explosion-proof electricals, bonding and grounding of containers, and no open flames. Grounding a drum requires bare metal contact; paint buildup on clamps breaks continuity.

Spontaneous combustion: solvent-soaked rags and booth filter media must go into a self-closing metal container with water or be laid flat outdoors; piles of rags can self-heat and ignite without an ignition source.

Waste streams: waste thinner, gun-cleaning sludge, and leftover catalysed paint are hazardous waste. Waste paint should be catalysed and cured solid before disposal where the jurisdiction permits; liquid waste requires a licensed carrier and manifest documentation.

Eyewash and spill response: eyewash stations must be within 10 seconds' travel (about 15 m) of acid/alkali and solvent use areas, unobstructed, and flushed weekly. Spill kits should include absorbent, non-sparking scoop, and disposal bags.

Heat stress: booth temperatures above 30 °C with full PPE raise core temperature; work-rest cycles, hydration, and cooling vests reduce risk. Symptoms progress from cramps to heat exhaustion (clammy skin, confusion) to heat stroke (hot dry skin, loss of consciousness).

Air supply: a refrigerated dryer delivers a pressure dew point around 3 °C; a desiccant dryer achieves -40 °C for critical clearcoat work. Coalescing filters remove oil aerosol; a final filter at the gun removes particulate. A 0.01 micron coalescing filter is standard before the spray gun.

Compressor sizing: a gun consuming 200 L/min (7 CFM) at 3 bar needs a compressor delivering at least 1.5 times that free air delivery to avoid pressure drop during continuous spraying. Receiver size buffers demand spikes; undersized receivers cause pressure fluctuation and orange peel.

Booth maintenance: intake and exhaust filters are replaced on pressure-drop readings, not calendar dates. A rising booth pressure differential reduces airflow and causes overspray to settle on the wet film. Booth airflow should be checked with a velometer at the filter face.

Gun cleaning: disassemble, soak in solvent, and clean fluid passages with a soft brush; never use a drill bit or wire to clear a nozzle because it changes the orifice geometry. Lubricate needle packing and air valve with a silicone-free lubricant.

HVLP vs. conventional: HVLP is limited to 10 psi (0.7 bar) at the cap and transfers 65% or more of material; conventional high-pressure atomizes finer but transfers 25-40%. LVLP sits between, using low pressure with higher transfer efficiency than conventional.

Fluid tip selection: tip size is chosen by material viscosity and film build, not by gun brand. Typical ranges: 1.2-1.3 mm for clearcoat and basecoat, 1.4-1.5 mm for primer surfacer, 1.6-1.8 mm for high-build primer and heavy-bodied products.

Measuring equipment: viscosity is measured with a Zahn cup (seconds to drain) or Ford cup; film thickness with a magnetic or eddy-current gauge on steel and aluminium. Measure wet film with a comb and calculate dry film from the volume solids percentage.

Lighting: colour matching requires a colour-corrected light source (D65 or equivalent) at 1000-2000 lux; standard fluorescent lighting has a discontinuous spectrum and shifts metameric matches.

Substrate identification: steel is magnetic; aluminium, plastic, and fibreglass are not. A magnet test distinguishes steel from aluminium but not from plastic. Burn test or sanding dust characteristics help identify plastic versus fibreglass.

Plastic repair: identify the plastic type from the ISO code stamped on the back of the part (PP, PE, ABS, PC, PA, PUR). PP and PE require flame treatment or adhesion promoter and cannot be repaired with standard fillers; flexible parts need flexible additive in the primer and clear.

Bare steel preparation: remove rust to bare metal, treat with a metal conditioner (phosphoric acid wash) followed by a conversion coating, then apply an epoxy primer within the product's recoat window. Do not apply etch primer over galvanized steel or zinc-coated panels.

Aluminium: sand with 180-220 grit, apply a self-etching or epoxy primer specifically rated for aluminium. Bare aluminium oxidizes within hours; primer should be applied the same day as sanding.

Galvanized steel: do not sand through the zinc layer. Clean with a solvent or mild acid wash, apply a wash primer or epoxy primer rated for zinc, and avoid products containing zinc or unreacted acid that cause blistering.

Film thickness and sanding: primer surfacer is typically applied 100-150 microns wet and sanded to 400-600 grit before basecoat. Sanding scratches finer than the topcoat's hiding power telegraph through; coarser scratches show as sandscratch swelling.

Contamination testing: water-break test (water beads indicate contamination) and solvent wipe with a clean lint-free cloth. Silicone contamination causes fisheyes; it is removed only by sanding back to bare substrate, not by solvent wiping.

Adhesion testing: cross-hatch (ISO 2409) or pull-off (ASTM D4541) after cure. Failure at the substrate interface indicates poor preparation; failure within the primer indicates insufficient cure or film build.

Colour measurement: spectrophotometers read Lab* values (L* lightness, a* red-green, b* yellow-blue). Delta E (ΔE) quantifies the difference between the sample and the formula; ΔE below 1.0 is generally not visible to the eye, ΔE above 2.0 is visible.

Metamerism: a match that looks correct under one light source but wrong under another is metameric. It occurs when the pigment composition differs from the original. Reduce it by matching pigment type, not only the measured colour.

Three-angle matching: metallic and pearlescent colours are matched at three angles (face, 45°, and flop or near-gloss). Face is the direct view, flop is the side view. The flop index describes the lightness change with angle.

Tinting strategy: adjust the dominant pigment first, then the secondary, then the flop. Adding black to darken also reduces chroma and shifts hue; use a chromatic darkener or adjust with complementary pigments to preserve saturation.

Mixing rules: mix by weight with a scale accurate to 0.1 g; volume mixing is inaccurate for small quantities. Add tints in small increments (typically less than 5% of total volume) and record each addition to reproduce the formula.

Pot life: catalysed products have a fixed pot life (often 4-8 hours for 2K clear, 24-48 hours for some epoxies) that shortens with temperature. Do not add fresh product to a pot that has started to gel; the gel particles will not disperse.

Formula documentation: record the mixing bank code, variant, product batch, and any manual tint additions. Variants correct for factory colour differences between plants and model years; the variant code is often on the vehicle's compliance plate.

Spray-out panels: always spray a test panel of the mixed colour and compare under the same lighting as the vehicle. Wet and dry films differ in colour; compare after flash-off, not while wet.

Epoxy primer: two-component, provides corrosion protection and adhesion on bare metal; recoat window is typically 7 days at 20 °C, after which it must be sanded. Epoxy is not sanded easily and is not a filler.

Etch primer: acid-based, provides adhesion to bare steel and aluminium; film build is thin (10-15 microns). Do not apply over body filler, galvanized steel, or previously painted surfaces, and do not topcoat with polyester products.

Primer surfacer: high-build product that fills sanding scratches and minor imperfections; applied 100-150 microns and sanded. It is porous and must be sealed before topcoat on bare or repaired areas.

Sealer: a thin coat applied over primer or old finish to prevent solvent penetration and colour bleed, and to promote topcoat adhesion. Sealers are tinted to the topcoat colour to improve hiding and reduce the number of basecoat coats.

Flexible additive: added to primer and clearcoat at the manufacturer's ratio (often 10-30%) for plastic bumpers and flexible parts; without it the film cracks when the part flexes.

Recoat windows: applying the next coat outside the recoat window without sanding causes intercoat adhesion failure or lifting. Solvent trapped between coats causes solvent pop during baking.

Guide coat: a contrasting mist coat applied over primer surfacer to reveal low spots and sanding scratches during blocking. Remove all guide coat before topcoat; leftover guide coat shows through as dark speckles.

Primer sanding: use a sanding block with 320-400 grit for primer surfacer, 600-800 grit for sealer. Sanding through to bare metal requires re-priming; sanding through the sealer requires re-sealing.

Basecoat application: apply in thin, even coats at 50% overlap; the first coat is a tack coat. Waterborne basecoat requires flash-off between coats and forced drying before clearcoat; solventborne basecoat flashes off by solvent evaporation.

Basecoat hiding: coverage is judged by the film's opacity, not by the number of coats. Metallic basecoats are applied to hiding plus one additional coat to orient the metallic flakes; over-application causes mottling and flop loss.

Clearcoat film build: typical clearcoat dry film is 40-60 microns. Too thin causes UV degradation and poor gloss; too thick causes solvent pop, cracking, and runs. Measure with a film thickness gauge after cure.

Spray technique: gun distance 15-20 cm, gun perpendicular to the surface, speed constant, 50% overlap. Arcing at panel edges causes dry spray; tilting the gun causes uneven film and runs.

Flash-off and bake: flash-off time depends on temperature and airflow; baking before solvent escapes causes solvent pop and blisters. Typical bake is 60 °C for 30 minutes for 2K products, but follow the product data sheet.

Orange peel: caused by insufficient atomization, too-high viscosity, too-fast solvent, or gun too far away. Reduce by increasing atomization pressure, thinning to the correct viscosity, or slowing the solvent.

Runs and sags: caused by too-heavy coats, gun too close, or too-slow solvent. Remove runs after cure by sanding and polishing; do not attempt to brush out a run in wet clearcoat.

Dust and contamination: tack off the surface immediately before topcoat; booth airflow should be on during spraying and remain on during flash-off to carry overspray away from the wet film.

Candy colours: a transparent tinted mid-coat over a metallic base; the final colour depends on the basecoat shade and the number of candy coats. Record the base shade and coat count to reproduce the finish.

Pearl and mica: effect pigments that shift colour with viewing angle. Apply over a ground coat matched to the pearl's undertone; too many coats reduces the flop and dulls the effect.

Matte and satin clear: flattening agents reduce gloss; the finish is sensitive to polishing and to film thickness variation. Matte clear cannot be sanded and polished to restore gloss because polishing changes the gloss level.

Airbrush and custom art: use a reduced-viscosity paint and low pressure; mask with fine-line tape and remove tape while the paint is still soft to avoid pulling the film. Clearcoat over art after full cure of the art layers.

Vinyl wrap and graphics: surface must be clean and smooth; wrap does not hide bodywork defects. Film thickness under the wrap affects adhesion; edges require primer or adhesive promoter.

Special-effect pigments: chameleon and interference pigments require a specific base colour and clearcoat; they are typically applied over black or a matched ground coat and cannot be tinted into a standard mixing bank formula.

Two-tone and stripe layout: measure and mark the break line before masking; use a consistent reference point on both sides. The break line should follow a body character line, and the clearcoat must cover both colours to seal the edge.

Cure and durability of custom finishes: extra clearcoat coats increase film build and UV protection but increase the risk of solvent pop; allow longer flash-off between coats and control booth temperature.

Fisheyes: circular craters caused by silicone, oil, or wax contamination. Remedy: sand back to the substrate, clean with a proper solvent, and add fisheye eliminator only as a last resort because it can cause adhesion problems.

Solvent pop: small blisters or pinholes caused by trapped solvent escaping during bake. Prevent by longer flash-off, thinner coats, slower solvent, and lower bake temperature; repair by sanding out and recoating.

Orange peel: textured surface from poor atomization or film flow. Repair by sanding with 1500-2000 grit and polishing, or by refinishing if severe; polishing removes only a few microns.

Sags and runs: excess material flowing under gravity. Remove after cure with a run razor or sanding block, then polish or refinish. Prevention is thinner coats and correct gun distance and speed.

Adhesion failure: peeling or flaking from poor preparation, contamination, or exceeding the recoat window. Diagnose with a cross-hatch or pull-off test; repair requires removing the failed film back to a sound substrate.

Colour mismatch: check under the correct light source and at multiple angles. If the formula is correct but the variant is wrong, adjust with a variant or blend into adjacent panels rather than tinting the whole mix.

Sandscratch swelling: sanding scratches reappear after topcoat because solvent swells the primer. Prevent by sanding finer and sealing; repair by sanding back and re-priming.

Dirt nibs: particles in the finish. Remove by sanding with 1500-2000 grit and polishing, or by nibbing and recoating. Prevention is booth cleanliness, tack-off, and filtered air.

Fluid tip and air cap: the fluid tip controls material flow; the air cap controls atomization pattern. A worn tip or needle causes an uneven pattern and increased material use; replace as a set.

Pattern test: spray a test pattern on cardboard at the working distance. A correct pattern is uniform with a soft edge; a split or heavy-centre pattern indicates a clogged or damaged air cap or a misaligned tip.

Pressure settings: HVLP is set at the cap to 10 psi or less; the gun inlet pressure is higher because of hose losses. Use a gauge at the gun inlet, not at the compressor, to set pressure.

Fluid adjustment: set the fluid needle so the pattern is fully atomized at the working distance; opening the fluid too far causes runs and poor atomization. Adjust air first, then fluid, then pattern width.

Viscosity: measure with a Zahn cup at the temperature specified by the product data sheet. Cold material is thicker; warm it or adjust thinner to the specified drain time.

Gun troubleshooting: spitting indicates a loose or dirty fluid tip or a worn needle packing; a pulsating pattern indicates air supply fluctuation or a partially clogged fluid passage; a curved pattern indicates a damaged air cap.

Cleaning and storage: flush with solvent after each use, clean the air cap holes with a soft brush or toothpick, and store the gun with the needle backed off to protect the seat. Never immerse the entire gun in solvent.

Air consumption: check the gun's CFM requirement against the compressor's delivery at the working pressure. A gun that needs 200 L/min at 3 bar will starve on a compressor rated at 200 L/min free air delivery because of hose and filter losses.

Work order documentation: record the vehicle identification number, colour code and variant, panel list, and the products and batches used. This record supports warranty claims and future colour matching.

Estimate vs. supplement: an estimate lists visible damage; a supplement documents hidden damage found after disassembly. Supplements require customer or insurer authorization before additional work proceeds.

Customer communication: explain the difference between a blend and a full panel refinish, including cost and colour-match risk. Obtain written approval for blend decisions and for any deviation from the original estimate.

Warranty terms: state the warranty period, what it covers (adhesion, colour match, gloss), and what voids it (improper care, aftermarket products, accidents). Provide the customer with care instructions for the first 30 days.

Material safety documentation: keep safety data sheets accessible for every product in the shop and provide them on request. Record the products used on each vehicle for traceability.

Colour code documentation: record the colour code from the compliance plate and the variant used. If the variant is not available, document the manual tint additions so the match can be reproduced.

Invoice accuracy: itemize materials, labour hours, and sublet work. Discrepancies between the estimate and invoice must be explained and approved before the customer takes delivery.

Handover inspection: inspect the vehicle with the customer under proper lighting, note any pre-existing damage on the check-in sheet, and document the final inspection with photos.

Isocyanate exposure: sensitization can occur after a single overexposure; once sensitized, any further exposure can trigger asthma. Supplied-air respirators are required for spraying 2K isocyanate products in most jurisdictions; dust masks and cartridge respirators do not protect against isocyanate vapour.

Respirator fit: qualitative fit testing (saccharin, Bitrex) is acceptable for half-mask respirators; quantitative fit testing (PortaCount) is required for full-face and supplied-air units. Re-fit test annually and after facial changes such as weight change or dental work.

VOC limits: solventborne basecoat and clearcoat are regulated by VOC content (g/L minus water and exempt solvents). Compliant coatings are typically waterborne basecoat plus high-solids clearcoat; mixing compliant and non-compliant products does not change the regulated category of the resulting mix.

Flash point and fire safety: solvents with flash points below 23 °C (Class I) require explosion-proof electricals, bonding and grounding of containers, and no open flames. Grounding a drum requires bare metal contact; paint buildup on clamps breaks continuity.

Spontaneous combustion: solvent-soaked rags and booth filter media must go into a self-closing metal container with water or be laid flat outdoors; piles of rags can self-heat and ignite without an ignition source.

Waste streams: waste thinner, gun-cleaning sludge, and leftover catalysed paint are hazardous waste. Waste paint should be catalysed and cured solid before disposal where the jurisdiction permits; liquid waste requires a licensed carrier and manifest documentation.

Eyewash and spill response: eyewash stations must be within 10 seconds' travel (about 15 m) of acid/alkali and solvent use areas, unobstructed, and flushed weekly. Spill kits should include absorbent, non-sparking scoop, and disposal bags.

Heat stress: booth temperatures above 30 °C with full PPE raise core temperature; work-rest cycles, hydration, and cooling vests reduce risk. Symptoms progress from cramps to heat exhaustion (clammy skin, confusion) to heat stroke (hot dry skin, loss of consciousness).

Air supply: a refrigerated dryer delivers a pressure dew point around 3 °C; a desiccant dryer achieves -40 °C for critical clearcoat work. Coalescing filters remove oil aerosol; a final filter at the gun removes particulate. A 0.01 micron coalescing filter is standard before the spray gun.

Compressor sizing: a gun consuming 200 L/min (7 CFM) at 3 bar needs a compressor delivering at least 1.5 times that free air delivery to avoid pressure drop during continuous spraying. Receiver size buffers demand spikes; undersized receivers cause pressure fluctuation and orange peel.

Booth maintenance: intake and exhaust filters are replaced on pressure-drop readings, not calendar dates. A rising booth pressure differential reduces airflow and causes overspray to settle on the wet film. Booth airflow should be checked with a velometer at the filter face.

Gun cleaning: disassemble, soak in solvent, and clean fluid passages with a soft brush; never use a drill bit or wire to clear a nozzle because it changes the orifice geometry. Lubricate needle packing and air valve with a silicone-free lubricant.

HVLP vs. conventional: HVLP is limited to 10 psi (0.7 bar) at the cap and transfers 65% or more of material; conventional high-pressure atomizes finer but transfers 25-40%. LVLP sits between, using low pressure with higher transfer efficiency than conventional.

Fluid tip selection: tip size is chosen by material viscosity and film build, not by gun brand. Typical ranges: 1.2-1.3 mm for clearcoat and basecoat, 1.4-1.5 mm for primer surfacer, 1.6-1.8 mm for high-build primer and heavy-bodied products.

Measuring equipment: viscosity is measured with a Zahn cup (seconds to drain) or Ford cup; film thickness with a magnetic or eddy-current gauge on steel and aluminium. Measure wet film with a comb and calculate dry film from the volume solids percentage.

Lighting: colour matching requires a colour-corrected light source (D65 or equivalent) at 1000-2000 lux; standard fluorescent lighting has a discontinuous spectrum and shifts metameric matches.

Substrate identification: steel is magnetic; aluminium, plastic, and fibreglass are not. A magnet test distinguishes steel from aluminium but not from plastic. Burn test or sanding dust characteristics help identify plastic versus fibreglass.

Plastic repair: identify the plastic type from the ISO code stamped on the back of the part (PP, PE, ABS, PC, PA, PUR). PP and PE require flame treatment or adhesion promoter and cannot be repaired with standard fillers; flexible parts need flexible additive in the primer and clear.

Bare steel preparation: remove rust to bare metal, treat with a metal conditioner (phosphoric acid wash) followed by a conversion coating, then apply an epoxy primer within the product's recoat window. Do not apply etch primer over galvanized steel or zinc-coated panels.

Aluminium: sand with 180-220 grit, apply a self-etching or epoxy primer specifically rated for aluminium. Bare aluminium oxidizes within hours; primer should be applied the same day as sanding.

Galvanized steel: do not sand through the zinc layer. Clean with a solvent or mild acid wash, apply a wash primer or epoxy primer rated for zinc, and avoid products containing zinc or unreacted acid that cause blistering.

Film thickness and sanding: primer surfacer is typically applied 100-150 microns wet and sanded to 400-600 grit before basecoat. Sanding scratches finer than the topcoat's hiding power telegraph through; coarser scratches show as sandscratch swelling.

Contamination testing: water-break test (water beads indicate contamination) and solvent wipe with a clean lint-free cloth. Silicone contamination causes fisheyes; it is removed only by sanding back to bare substrate, not by solvent wiping.

Adhesion testing: cross-hatch (ISO 2409) or pull-off (ASTM D4541) after cure. Failure at the substrate interface indicates poor preparation; failure within the primer indicates insufficient cure or film build.

Colour measurement: spectrophotometers read Lab* values (L* lightness, a* red-green, b* yellow-blue). Delta E (ΔE) quantifies the difference between the sample and the formula; ΔE below 1.0 is generally not visible to the eye, ΔE above 2.0 is visible.

Metamerism: a match that looks correct under one light source but wrong under another is metameric. It occurs when the pigment composition differs from the original. Reduce it by matching pigment type, not only the measured colour.

Three-angle matching: metallic and pearlescent colours are matched at three angles (face, 45°, and flop or near-gloss). Face is the direct view, flop is the side view. The flop index describes the lightness change with angle.

Tinting strategy: adjust the dominant pigment first, then the secondary, then the flop. Adding black to darken also reduces chroma and shifts hue; use a chromatic darkener or adjust with complementary pigments to preserve saturation.

Mixing rules: mix by weight with a scale accurate to 0.1 g; volume mixing is inaccurate for small quantities. Add tints in small increments (typically less than 5% of total volume) and record each addition to reproduce the formula.

Pot life: catalysed products have a fixed pot life (often 4-8 hours for 2K clear, 24-48 hours for some epoxies) that shortens with temperature. Do not add fresh product to a pot that has started to gel; the gel particles will not disperse.

Formula documentation: record the mixing bank code, variant, product batch, and any manual tint additions. Variants correct for factory colour differences between plants and model years; the variant code is often on the vehicle's compliance plate.

Spray-out panels: always spray a test panel of the mixed colour and compare under the same lighting as the vehicle. Wet and dry films differ in colour; compare after flash-off, not while wet.

Epoxy primer: two-component, provides corrosion protection and adhesion on bare metal; recoat window is typically 7 days at 20 °C, after which it must be sanded. Epoxy is not sanded easily and is not a filler.

Etch primer: acid-based, provides adhesion to bare steel and aluminium; film build is thin (10-15 microns). Do not apply over body filler, galvanized steel, or previously painted surfaces, and do not topcoat with polyester products.

Primer surfacer: high-build product that fills sanding scratches and minor imperfections; applied 100-150 microns and sanded. It is porous and must be sealed before topcoat on bare or repaired areas.

Sealer: a thin coat applied over primer or old finish to prevent solvent penetration and colour bleed, and to promote topcoat adhesion. Sealers are tinted to the topcoat colour to improve hiding and reduce the number of basecoat coats.

Flexible additive: added to primer and clearcoat at the manufacturer's ratio (often 10-30%) for plastic bumpers and flexible parts; without it the film cracks when the part flexes.

Recoat windows: applying the next coat outside the recoat window without sanding causes intercoat adhesion failure or lifting. Solvent trapped between coats causes solvent pop during baking.

Guide coat: a contrasting mist coat applied over primer surfacer to reveal low spots and sanding scratches during blocking. Remove all guide coat before topcoat; leftover guide coat shows through as dark speckles.

Primer sanding: use a sanding block with 320-400 grit for primer surfacer, 600-800 grit for sealer. Sanding through to bare metal requires re-priming; sanding through the sealer requires re-sealing.

Basecoat application: apply in thin, even coats at 50% overlap; the first coat is a tack coat. Waterborne basecoat requires flash-off between coats and forced drying before clearcoat; solventborne basecoat flashes off by solvent evaporation.

Basecoat hiding: coverage is judged by the film's opacity, not by the number of coats. Metallic basecoats are applied to hiding plus one additional coat to orient the metallic flakes; over-application causes mottling and flop loss.

Clearcoat film build: typical clearcoat dry film is 40-60 microns. Too thin causes UV degradation and poor gloss; too thick causes solvent pop, cracking, and runs. Measure with a film thickness gauge after cure.

Spray technique: gun distance 15-20 cm, gun perpendicular to the surface, speed constant, 50% overlap. Arcing at panel edges causes dry spray; tilting the gun causes uneven film and runs.

Flash-off and bake: flash-off time depends on temperature and airflow; baking before solvent escapes causes solvent pop and blisters. Typical bake is 60 °C for 30 minutes for 2K products, but follow the product data sheet.

Orange peel: caused by insufficient atomization, too-high viscosity, too-fast solvent, or gun too far away. Reduce by increasing atomization pressure, thinning to the correct viscosity, or slowing the solvent.

Runs and sags: caused by too-heavy coats, gun too close, or too-slow solvent. Remove runs after cure by sanding and polishing; do not attempt to brush out a run in wet clearcoat.

Dust and contamination: tack off the surface immediately before topcoat; booth airflow should be on during spraying and remain on during flash-off to carry overspray away from the wet film.

Candy colours: a transparent tinted mid-coat over a metallic base; the final colour depends on the basecoat shade and the number of candy coats. Record the base shade and coat count to reproduce the finish.

Pearl and mica: effect pigments that shift colour with viewing angle. Apply over a ground coat matched to the pearl's undertone; too many coats reduces the flop and dulls the effect.

Matte and satin clear: flattening agents reduce gloss; the finish is sensitive to polishing and to film thickness variation. Matte clear cannot be sanded and polished to restore gloss because polishing changes the gloss level.

Airbrush and custom art: use a reduced-viscosity paint and low pressure; mask with fine-line tape and remove tape while the paint is still soft to avoid pulling the film. Clearcoat over art after full cure of the art layers.

Vinyl wrap and graphics: surface must be clean and smooth; wrap does not hide bodywork defects. Film thickness under the wrap affects adhesion; edges require primer or adhesive promoter.

Special-effect pigments: chameleon and interference pigments require a specific base colour and clearcoat; they are typically applied over black or a matched ground coat and cannot be tinted into a standard mixing bank formula.

Two-tone and stripe layout: measure and mark the break line before masking; use a consistent reference point on both sides. The break line should follow a body character line, and the clearcoat must cover both colours to seal the edge.

Cure and durability of custom finishes: extra clearcoat coats increase film build and UV protection but increase the risk of solvent pop; allow longer flash-off between coats and control booth temperature.

Fisheyes: circular craters caused by silicone, oil, or wax contamination. Remedy: sand back to the substrate, clean with a proper solvent, and add fisheye eliminator only as a last resort because it can cause adhesion problems.

Solvent pop: small blisters or pinholes caused by trapped solvent escaping during bake. Prevent by longer flash-off, thinner coats, slower solvent, and lower bake temperature; repair by sanding out and recoating.

Orange peel: textured surface from poor atomization or film flow. Repair by sanding with 1500-2000 grit and polishing, or by refinishing if severe; polishing removes only a few microns.

Sags and runs: excess material flowing under gravity. Remove after cure with a run razor or sanding block, then polish or refinish. Prevention is thinner coats and correct gun distance and speed.

Adhesion failure: peeling or flaking from poor preparation, contamination, or exceeding the recoat window. Diagnose with a cross-hatch or pull-off test; repair requires removing the failed film back to a sound substrate.

Colour mismatch: check under the correct light source and at multiple angles. If the formula is correct but the variant is wrong, adjust with a variant or blend into adjacent panels rather than tinting the whole mix.

Sandscratch swelling: sanding scratches reappear after topcoat because solvent swells the primer. Prevent by sanding finer and sealing; repair by sanding back and re-priming.

Dirt nibs: particles in the finish. Remove by sanding with 1500-2000 grit and polishing, or by nibbing and recoating. Prevention is booth cleanliness, tack-off, and filtered air.

Fluid tip and air cap: the fluid tip controls material flow; the air cap controls atomization pattern. A worn tip or needle causes an uneven pattern and increased material use; replace as a set.

Pattern test: spray a test pattern on cardboard at the working distance. A correct pattern is uniform with a soft edge; a split or heavy-centre pattern indicates a clogged or damaged air cap or a misaligned tip.

Pressure settings: HVLP is set at the cap to 10 psi or less; the gun inlet pressure is higher because of hose losses. Use a gauge at the gun inlet, not at the compressor, to set pressure.

Fluid adjustment: set the fluid needle so the pattern is fully atomized at the working distance; opening the fluid too far causes runs and poor atomization. Adjust air first, then fluid, then pattern width.

Viscosity: measure with a Zahn cup at the temperature specified by the product data sheet. Cold material is thicker; warm it or adjust thinner to the specified drain time.

Gun troubleshooting: spitting indicates a loose or dirty fluid tip or a worn needle packing; a pulsating pattern indicates air supply fluctuation or a partially clogged fluid passage; a curved pattern indicates a damaged air cap.

Cleaning and storage: flush with solvent after each use, clean the air cap holes with a soft brush or toothpick, and store the gun with the needle backed off to protect the seat. Never immerse the entire gun in solvent.

Air consumption: check the gun's CFM requirement against the compressor's delivery at the working pressure. A gun that needs 200 L/min at 3 bar will starve on a compressor rated at 200 L/min free air delivery because of hose and filter losses.

Work order documentation: record the vehicle identification number, colour code and variant, panel list, and the products and batches used. This record supports warranty claims and future colour matching.

Estimate vs. supplement: an estimate lists visible damage; a supplement documents hidden damage found after disassembly. Supplements require customer or insurer authorization before additional work proceeds.

Customer communication: explain the difference between a blend and a full panel refinish, including cost and colour-match risk. Obtain written approval for blend decisions and for any deviation from the original estimate.

Warranty terms: state the warranty period, what it covers (adhesion, colour match, gloss), and what voids it (improper care, aftermarket products, accidents). Provide the customer with care instructions for the first 30 days.

Material safety documentation: keep safety data sheets accessible for every product in the shop and provide them on request. Record the products used on each vehicle for traceability.

Colour code documentation: record the colour code from the compliance plate and the variant used. If the variant is not available, document the manual tint additions so the match can be reproduced.

Invoice accuracy: itemize materials, labour hours, and sublet work. Discrepancies between the estimate and invoice must be explained and approved before the customer takes delivery.

Handover inspection: inspect the vehicle with the customer under proper lighting, note any pre-existing damage on the check-in sheet, and document the final inspection with photos.