Lesson Notes By Weeks and Term v3 - Senior Secondary 3
Matching Colour
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Matching Colour
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Subject: Auto body repair And Spray painting
Class: Senior Secondary 3
Term: 3rd Term
Week: 2
Theme: Auto-Body Spray Painting
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Students should be ableto;determine the or iginal factory colour and list colour used on auto-body State guides thataid selecting matchedcolours.
the sticker is missing or illegible, the technician would use the VIN (from the dashboard or registration) and consult a paint manufacturer's database (e.g., PPG's local database) to retrieve the "040" formula.
2. List Colour Type: "Super White" is a solid colour. It will be a basecoat-clearcoat system.
3. Guides for Selecting Matched Colours: Mix Paint: The technician mixes the "040" formula according to the paint mixing system's specifications.
Prepare Spray-Out Card: A test card is prepared and sprayed with the mixed "040" basecoat and then clearcoat.
Visual Comparison: The technician takes the dried spray-out card and compares it to the original "Super White" on the fender of the Corolla. This is done under natural daylight (e.g., outside the workshop if conditions are good, or under a colour-corrected lamp inside).
Observe Fading: The technician observes that the original paint on the car has slightly yellowed over time due to sun exposure in Lagos. The freshly mixed "040" on the test card appears slightly brighter/whiter.
Tinting Adjustment: Based on visual assessment, the technician adds a tiny amount of a yellow or reddish toner to the "040" formula to subtly warm up the white, making it closer to the aged paint on the car.
Re-Test: Another spray-out card is prepared with the adjusted formula and re-evaluated under various lights and angles until a satisfactory match is achieved before painting the bumper.
Blending Consideration: Even with a good match, the technician plans to "blend" the paint slightly into the adjacent fenders to ensure a seamless transition between the new bumper and the existing body panels. and blues have a pearl effect (e.g., some Toyota Pearl White, Honda White Orchid Pearl).
Matching Challenge: The most difficult to match due to the multi-stage application (basecoat, mid-coat with pearl, clearcoat) and the highly sensitive nature of the pearl layer's application. The mid-coat thickness and number of layers drastically alter the final appearance.
Layers: Basecoat (solid colour) + Mid-coat (with pearl flakes) + Clearcoat. C. Guides that Aid in Selecting Matched Colours Achieving a perfect colour match requires a systematic approach and attention to detail.
1. Retrieve Original Paint Code: As detailed in section A, this is the essential starting point.
2. Prepare Test Panels / Spray-Out Cards: Purpose: Crucial for metallic and pearlescent colours. A small sample of the mixed paint is sprayed onto a dedicated test card or a scrap panel, mimicking the actual application process on the vehicle.
Procedure: Spray 2-3 coats, followed by clearcoat, just as on the actual vehicle. Allow to dry.
Benefit: This allows the technician to observe the actual colour, metallic "flop," and pearl effect before applying paint to the vehicle, enabling adjustments if needed.
3. Visual Comparison Under Varied Lighting Conditions: Natural Daylight (Overcast Sky Preferred): The most accurate and neutral light source. An overcast sky provides diffused light, minimising harsh shadows and reflections, which helps in seeing the true colour. Avoid direct sunlight as it can be deceptive. Artificial Daylight-Simulating Lights (Colour Corrected Lights): Modern workshops use specialised lamps (e.g., 5000K or 6500K colour temperature) that mimic natural daylight. These are vital for night work or in areas without sufficient natural light.
Angled Viewing: Always compare the test panel or mixed paint to the vehicle panel from multiple angles (straight on, 45 degrees, glancing angles) to assess metallic/pearl flop and undertones.
4. Consider Paint Fading/Ageing: Over time, vehicle paint fades due to exposure to UV radiation, environmental pollutants, and wear. This means the original factory colour code might no longer perfectly match the existing, aged paint.
Solution: After obtaining the factory code, slight tinting adjustments (adding small amounts of other toners like black, white, red, blue, or yellow) might be necessary to "shift" the mixed colour to match the faded paint. This is an art requiring experience.
5. Use of Colour Swatches/Colour Chips: Paint manufacturers provide physical colour swatches (small painted cards) corresponding to their formulas.
Application: After identifying the paint code, the corresponding swatch can be used for an initial visual comparison with the vehicle's paint to confirm the base colour and identify any major discrepancies due to fading.
6. Panel-to-Panel Blending (Scuffing/Fading-in): Even with the best match, sometimes the transition between a new paint job and an old, aged one can be visible.
Technique: To minimise this, technicians often "blend" or "fade-in" the new paint into the adjacent panels by gradually thinning the colour as it extends onto the original panel. This diffuses the colour difference, making it less noticeable.
7. Proper Surface Preparation: The condition of the surface (cleanliness, smoothness, correct primer colour) significantly influences the final appearance of the paint. Any imperfections or incorrect primer colour can alter the perceived topcoat colour.
Worked Example (Nigerian Context): A customer brings a 2018 Toyota Corolla to a workshop in Ikeja, Lagos, for a bumper replacement and painting after a minor fender bender. The car is "Super White."
1. Determine Original Factory Colour: The technician first checks the driver's side door jamb for the paint code sticker. They find "040" listed under "C/TR". This is the Toyota Super White code.
Alternative: If the sticker is missing or illegible, the technician would use the VIN (from the dashboard or registration) and consult a paint manufacturer's database (e.g., PPG's local database) to retrieve the "040" formula.
2. List Colour Type: "Super White" is a solid colour. It will be a basecoat-clearcoat system.
3. Guides for Selecting Matched Colours: Mix Paint: The technician mixes the "040" formula according to the paint mixing system's specifications.
Prepare Spray-Out Card: A test card is prepared and sprayed with the mixed "040" basecoat and then clearcoat. * *Visual This section provides detailed explanations of the core concepts related to matching colours in auto body repair. A. Determining the Original Factory Colour Accurately determining the original factory colour is the foundational step in colour matching. It ensures that the repair starts with the correct base formulation.
1. Vehicle Identification Number (VIN)
Decoding: The VIN is a unique 17-character alphanumeric code found on all vehicles. It typically contains information about the vehicle's manufacturer, model, year, and often, the paint code.
Location: VIN can usually be found on the dashboard (viewable through the windshield), driver's side door jamb, or vehicle registration documents.
Application: While the VIN itself doesn't directly provide the paint code, it can be used in manufacturer databases or online VIN decoders to retrieve the precise paint code specific to that vehicle at the time of manufacture.
2. Colour Codes on Vehicle Labels/Stickers: Most vehicle manufacturers place specific labels within the vehicle containing paint codes. These are the most direct and reliable sources.
Common Locations: Driver's Side Door Jamb: Often on the pillar when the door is open.
Under the Bonnet (Engine Bay): Usually on a sticker attached to the inner fender, radiator support, or firewall.
Boot (Trunk)
Lid or Floor: Sometimes on a sticker under the carpet or spare tyre cover.
Glove Compartment: Less common, but can be found.
Appearance: These codes are typically a short alphanumeric sequence (e.g., "040" for Toyota Super White, "NH-731P" for Honda Crystal Black Pearl). They might be labelled "Colour," "Paint Code," "C/TR," or similar.
3. Manufacturer's Paint Code Databases/Charts: Paint manufacturers (e.g., PPG, AkzoNobel, Sherwin-Williams, BASF commonly available in Nigeria) compile extensive databases of vehicle paint codes.
Method: Once the vehicle's paint code is located (via label or VIN lookup), it is entered into a paint mixing system. This system provides the precise formula (ratios of toners/pigments) required to mix the original factory colour.
4. Spectro-photometers (Advanced Tool): For highly precise matching, especially on aged or faded paint, spectrophotometers are used. These electronic devices read the existing colour on the vehicle and provide a digital colour formula.
Application: While not common in every Nigerian workshop due to cost, it's an important tool for high-end repairs and can give the most accurate starting point, compensating for paint ageing. B. Listing Colours Used on Auto-body (Types of Paint Systems) Understanding the different types of paint systems is crucial because each behaves differently during application and requires specific matching considerations.
1. Solid Colours: Description: These are single-stage (older) or basecoat-clearcoat (modern) paints that contain no metallic flakes or mica particles. They have a uniform, non-sparkling appearance.
Examples: White, Black, Red, Blue.
Matching Challenge: While seemingly simpler, slight variations in toner ratios can lead to noticeable differences, especially with common colours like white.
Layers: Basecoat (for colour) + Clearcoat (for gloss and protection) in modern systems.
2. Metallic Colours: Description: Contain tiny metallic flakes (usually aluminium) that reflect light, giving the paint a shimmering or "sparkle" effect.
Examples: Silver, Gold, Bronze, various shades of metallic Blue/Red/Green.
Matching Challenge: Highly sensitive to application technique (spray gun pressure, speed, distance, overlap). The orientation of the metallic flakes ("flop") significantly affects the perceived colour from different angles.
Layers: Basecoat (with metallic flakes) + Clearcoat.
3. Pearlescent / Mica Colours (Also called "Pearl" or "Tri-coat"): Description: Contain mica particles or synthetic pearl flakes that create a multi-layered, iridescent effect, often with a different hue visible at different angles (a "colour shift").
Examples: Many modern whites, silvers, and blues have a pearl effect (e.g., some Toyota Pearl White, Honda White Orchid Pearl).
Matching Challenge: The most difficult to match due to the multi-stage application (basecoat, mid-coat with pearl, clearcoat) and the highly sensitive nature of the pearl layer's application. The mid-coat thickness and number of layers drastically alter the final appearance.
Layers: Basecoat (solid colour) + Mid-coat (with pearl flakes) + Clearcoat. C. Guides that Aid in Selecting Matched Colours Achieving a perfect colour match requires a systematic approach and attention to detail. 1. *Retrieve Original Paint Teacher Activities: Introduction (10 minutes): Begin by discussing the importance of colour matching in auto body repair, showing examples of good and bad matches (visual aids, pictures, or short video clips). Relate it to the economic impact on vehicle value and customer satisfaction in Nigeria. Content Delivery - Determining Original Colour (20 minutes): Explain the concept of VIN and its use. Show a diagram of a VIN or point one out on a sample vehicle if available. Identify and show the common locations for colour code stickers on a sample vehicle (or detailed diagrams/posters of door jambs, engine bays, etc.). Explain how to read typical Nigerian vehicle paint code formats (e.g., for Toyota, Honda, Innoson, Mercedes). Briefly discuss the role of manufacturer databases and spectrophotometers. Content Delivery - Types of Paint Systems (20 minutes): Explain and differentiate between solid, metallic, and pearlescent (tri-coat) paint systems. Use paint samples or visuals to illustrate the unique appearance of each type. Discuss the specific challenges associated with matching metallic and pearlescent colours (e.g., "flop" effect, multiple layers). Content Delivery - Guides for Matching (20 minutes): Explain each guide thoroughly: paint code retrieval, test panels/spray-out cards, visual comparison under varied lighting (natural daylight, artificial colour-corrected lights), accounting for fading, use of swatches, and blending techniques. Demonstrate how to prepare a spray-out card (if materials are available, otherwise use a video demonstration). Emphasise the need for multiple viewing angles. Practical Demonstration / Discussion (15 minutes): If a vehicle or body panel is available, demonstrate how to locate the colour code. Show how to visually compare a paint swatch to an aged vehicle panel. Facilitate a class discussion on the observed differences and potential causes (e.g., sun, environment).
Q&A and Summary (5 minutes): Address any student questions and summarise key learning points.
Student Activities: Group Discussion (10 minutes): Students, in small groups, discuss why colour matching is difficult and its importance in the Nigerian context (e.g., accident repairs, resale value of vehicles like Sienna, Corolla, Prado).
Practical Identification (15 minutes): Using provided diagrams of vehicle parts (door jambs, engine bays) or actual vehicles (if accessible), students locate and identify potential locations for VIN and paint code stickers. Students attempt to read and record sample paint codes.
Visual Comparison Exercise (15 minutes): Students are provided with various paint swatches (solid, metallic, pearl) and a slightly aged car panel (or a picture of one). They practice comparing the swatches to the aged panel under different light conditions (e.g., near a window for natural light, under classroom fluorescent lights) and from different angles, noting the perceived differences.
Note-Taking (Throughout the lesson): Students take comprehensive notes on key concepts, definitions, and procedures.
Active Participation: Students actively participate in Q&A sessions and class discussions.
Accident Repairs in Nigerian Cities: In busy Nigerian cities like Lagos, Abuja, and Port Harcourt, vehicle accidents are frequent. Auto body repair shops constantly receive damaged vehicles that require panel beating and repainting. Accurate colour matching is crucial here to ensure the repaired parts blend seamlessly with the untouched areas, restoring the vehicle to its pre-accident condition. A poorly matched repair diminishes the vehicle's aesthetic appeal and often reduces its resale value.
Enhancing Vehicle Resale Value and Trade: The Nigerian used car market is vibrant. A vehicle with a noticeable colour mismatch from a previous repair is often viewed with suspicion by potential buyers, who might assume underlying damage or poor repair quality. A perfect colour match, however, maintains the vehicle's original factory look, making it more attractive and commanding a better price during resale or trade-in. This directly impacts the owner's investment and the profitability of car dealers. Entrepreneurship and Specialisation in Auto Refinishing: For individuals trained in auto body repair and spray painting, mastering colour matching opens doors to specialised services. Workshops that consistently deliver excellent colour matches build strong reputations and can attract premium clients. This skill can lead to entrepreneurial ventures focusing on high-end vehicle restoration, custom painting, or even becoming a dedicated paint mixing and matching specialist supplying other workshops in a community. This provides a direct path to self-employment and economic empowerment within the Nigerian informal and formal sectors.