CTVET Ghana Certificate II - Auto Body Repair & Spraying common mistakes
CTVET Ghana Certificate II - Auto Body Repair & Spraying · Understand the traps and how to avoid them.
When asked how to store or dispose of body-shop waste, candidates tip leftover thinner, basecoat, and used gun-cleaning solvent down the floor drain or into the yard, and put used masking paper and rags in the general bin.
The trainee copies what they see in small informal shops where there is no waste contractor, and treats liquids as 'just a little bit'. They have not learned that solvents and paint waste are hazardous waste and that absorbent, oily rags can self-ignite.
What to do instead
Learn the waste streams as a checklist: (1) waste thinner and gun-cleaning solvent go into a labelled, lidded, metal safety container for a licensed collector - never to drain or ground; (2) empty tins and hardened paint residue go to a licensed waste handler, not household bins; (3) solvent-soaked rags go in a lidded metal bin with a self-closing lid; (4) masking paper and cured plastic sheeting go to general waste only once dry. Practise sorting a set of sample items into the correct stream until it is automatic.
Candidates set up a spray job with the booth door open, wear only a dust mask or a surgical mask instead of a fitted respirator, and do not check that extraction is running before picking up the gun.
Isocyanate hardeners and solvent vapour are invisible, so the hazard feels abstract, and a proper respirator is uncomfortable in the heat. Trainees also confuse a dust mask (for particles) with a respirator (for vapour and particles).
What to do instead
Memorise the pre-spray safety sequence and state it in order: booth/extraction on and verified, respirator fit-checked (cover the cartridges and inhale - it should seal; exhale - no leak at the edges), correct cartridge type for the product (organic vapour plus particulate pre-filter for two-pack paints), skin covered, eye protection on, doors closed. Be able to explain why a dust mask gives no protection against isocyanate vapour and why two-pack hardener sensitivity can develop after repeated exposure.
When asked to describe mixing a filler or a two-pack primer, candidates give a ratio from memory or 'by eye', add hardener until it 'looks right', and do not record the batch or pot life.
Experienced colleagues often mix by feel, and the trainee assumes the ratio is not critical. They have not internalised that hardener ratio controls cure, adhesion, and sandability, and that too much hardener causes shrinkage, pinholing, and cracking.
What to do instead
Learn to state the manufacturer's ratio exactly as printed (for example 2:1 by volume for a primer and its hardener, or a percentage by weight for filler hardener), and to use a mixing stick with marked graduations or a scale. Always say: read the technical data sheet, measure by volume or weight as specified, mix thoroughly including scraping the sides, note the pot life, and use within it. Be able to name the failure caused by excess hardener (brittle, cracked, poorly adhering film) and by too little (sticky, never fully cured).
Before painting, candidates wipe the panel once with thinners or a dirty rag, skip the tack rag, and spray over sanding dust, fingerprints, and silicone contamination.
The panel looks clean under workshop light, and thinners evaporate fast so it seems to 'clean and dry in one step'. Trainees do not know that ordinary thinner smears contamination rather than lifting it and leaves an oily residue that causes fish-eyes and poor adhesion.
What to do instead
Learn the standard preparation sequence and be able to justify each step: blow off or brush loose dust, wash with the correct wax-and-grease remover on a clean lint-free cloth (two-cloth method - one wet, one dry), allow to flash off, sand as required, re-clean, then tack-rag immediately before the first coat. Explain that silicone and wax cause fish-eyes and craters, and that a dedicated panel wipe - not gun-wash thinner - is the product for the job.
When describing how to remove a damaged bolt-on panel such as a front wing or door, candidates list only the visible bolts and forget hidden fasteners, wiring, and adjustment shims, then lever the panel off and damage the mounting flange or paint on adjacent panels.
They have only watched the job done once on one model and generalise. Hidden clips, adhesive, and connectors are the parts that break, and trainees underestimate how much force a stuck panel needs and where to apply it.
What to do instead
Adopt a written removal routine you can recite: photograph and mark hinge and alignment positions, disconnect the battery where wiring is involved, unplug connectors and release harness clips, remove trim and hidden fasteners (arch liners, bumper fixings, adhesive beads), support the panel, then release the last fixings. Use plastic wedges and a trim tool rather than a screwdriver on painted edges. Store removed panels and fasteners labelled by position so refitting is not guesswork.
After filling a dent, candidates sand the filler with a coarse disc on a high-speed grinder, gouge the surrounding paint and bare metal, and leave the repair area larger and thinner than it should be.
The grinder removes material fast and the trainee has not learned to control speed, pressure, and contact area, or to read the surface as they go. They also confuse 'removing the filler' with 'feathering the edge'.
What to do instead
Learn the grit progression and the feathering principle: shape filler while it is still slightly soft with a surform or coarse paper on a block, then finish with progressively finer grits on a sanding block, feathering the paint edge back so the repair is invisible after priming. Keep the grinder flat and moving, use the correct backing pad, and check with a hand over the surface and a guide coat. Be able to explain why heat from a grinder can warp a panel and why bare metal must be primed promptly.
When asked to set up a spray gun, candidates describe turning the fluid and air knobs without knowing which does what, test-spray onto the car, and hold the gun at varying distances and angles across the panel.
The three adjustments feel interchangeable and the trainee has never been taught a diagnostic routine. Without a test card and a consistent stroke, they cannot separate a gun fault from a technique fault.
What to do instead
Learn the setting sequence and be able to state it: set air pressure at the gun inlet with the trigger pulled, open the fluid knob and fan knob, then adjust fluid for the pattern width and fan for the shape, test-spray on a card or masking paper. Hold the gun perpendicular to the surface at a consistent distance (commonly around 15–20 cm, per the product sheet), overlap each pass by about half the fan width, and move at a steady speed from the wrist and forearm. Diagnose faults from the pattern: a split or heavy-centred pattern points to air and fluid balance, spitting to a dirty needle or cap.
Candidates describe colour matching as 'use the code on the plate', mix the basecoat, spray it, and are surprised by a visible mismatch, or they blame the paint when a metallic looks patchy.
They do not know that the same code varies by plant, batch, and fade, and that metallic orientation depends on technique. The colour code is treated as an absolute rather than a starting point.
What to do instead
Learn the matching routine: obtain the code, then check against the vehicle with a colour chip or spray-out card in daylight, adjust the variant if needed, and blend into adjacent panels rather than stopping at a hard edge. For metallics, keep gun distance, speed, pressure, and overlap consistent so the flake lies evenly, and apply the clearcoat within the product's window. Be able to explain why a blend panel is used and why a test card is sprayed before the vehicle.
When describing a panel gap or door alignment check, candidates judge it by eye from one position, tighten the hinges fully, and then find the door sits proud at one corner or the gap tapers along its length.
Alignment is a three-dimensional problem and a single viewing angle hides twist and tilt. The trainee also tightens before checking, so there is no adjustment left and the panel is stressed.
What to do instead
Learn the systematic check: view the gap from several angles, compare gap width top and bottom and front and back, check the panel is flush with its neighbours, and use a gap gauge or feeler gauge rather than the eye. Leave fixings just snug, adjust hinge position and shims to correct the gap before final torque, and recheck the latch and seal contact. Be able to say what causes a tapered gap (hinge tilt) versus a proud corner (twist) and how shims correct each.
When a customer asks for an estimate or complains about a repair, candidates either quote a figure on the spot without inspecting the vehicle or argue that the work was done correctly, and they do not write down what was agreed.
Trainees treat the counter conversation as a social chat rather than a commercial transaction, and they have not practised separating the technical facts from the customer's feelings. Fear of losing the job pushes them into a premature price.
What to do instead
Practise a short script: listen without interrupting, acknowledge the concern, ask clarifying questions, inspect the vehicle and explain what you found in plain language, then give a written estimate covering parts, labour, materials, and time, with what is and is not included. For complaints, restate the issue back, agree a next step and a date, and record it. Learn to explain a warranty position calmly and to refer a dispute you cannot settle to the supervisor rather than promising a free redo.