CPC30620 Painting common mistakes
CPC30620 Painting · Understand the traps and how to avoid them.
When asked to sequence surface preparation, the candidate lists sanding before surface cleaning and masking, or skips the contamination-removal step entirely and goes straight to coating.
Candidates memorise the visible steps of painting (sand, undercoat, topcoat) and treat cleaning and masking as incidental housekeeping rather than as ordered preparation stages that determine adhesion and finish quality.
What to do instead
Practise writing preparation sequences for at least six typical substrates (plasterboard, timber, masonry, metal, previously painted gloss, bare MDF), each starting with dust and grease removal, then repairs and filling, then sanding, then masking, then priming. Check each sequence against the principle that adhesion depends on a clean, sound, correctly abraded surface.
The candidate selects a coating system (primer, undercoat, topcoat) without matching it to the substrate, the service environment, or the manufacturer's stated recoat and overcoating times.
Candidates learn product names rather than product selection logic, and they underestimate how recoat windows, curing temperatures, and substrate porosity change the outcome.
What to do instead
Build a comparison table of the product families you use, listing substrate suitability, interior or exterior rating, recoat time at stated temperature, and thinning requirements. Answer practice questions by first naming the substrate and environment, then the product, then the timing, and state the reason for each choice.
When calculating paint quantities, the candidate divides total area by coverage without deducting openings, without allowing for the number of coats, and without rounding up to whole containers.
Candidates treat the calculation as a single arithmetic step and forget that coverage figures are per coat and per litre, and that real jobs need a wastage and touch-up allowance.
What to do instead
Use a fixed four-step method on every calculation: measure wall area, subtract doors and windows, multiply by the number of coats, divide by the stated coverage, then add a 10 per cent allowance and round up. Work through three worked examples with different ceiling heights and opening sizes until the method is automatic.
The candidate describes safe handling of solvents and two-pack products without naming ventilation, personal protective equipment, decanting controls, or fire precautions, and omits what to do with empty containers and waste.
Safety content is often studied as a list to recall rather than as a set of controls attached to a specific task, so candidates cannot apply it when a scenario is described.
What to do instead
For each product class (water-based, solvent-based, two-pack epoxy or polyurethane), write the controls under four headings: ventilation, PPE, storage and decanting, and waste disposal. Rehearse answering scenario questions by naming the hazard first, then the control, then the disposal route.
The candidate identifies a surface defect such as blistering, peeling, or picture framing but gives a generic remedy (sand and repaint) instead of diagnosing the cause and matching the repair to it.
Defect questions are answered from memory of the symptom rather than from a causal chain of moisture, contamination, incompatible coatings, or inadequate sanding between coats.
What to do instead
Create a defect chart with four columns: symptom, likely causes, diagnostic check, and correct repair. Cover at least eight common defects including blistering, sagging, brush marks, efflorescence, and poor adhesion, and for each write the one check that would confirm the cause before repair.
The candidate prepares and applies a finish without confirming the scope, the client's colour and sheen selection, or the acceptance standard, and cannot describe how the finished work would be inspected.
Candidates focus on technical application and treat planning, client sign-off, and quality inspection as administrative steps that are not examinable.
What to do instead
Practise writing a short job plan for a two-room interior repaint that states scope, surface preparation standard, products and sheen, number of coats, protection of adjacent surfaces, and the inspection criteria for each stage. Include a client confirmation point before final coats are applied.
The candidate estimates labour time for a job using a single rate for all surfaces, ignoring differences between cutting in, rolling large flat areas, spraying, and detailed trim work.
Candidates have limited site experience with productivity rates and assume area alone determines time, overlooking access, height, masking, and drying constraints between coats.
What to do instead
Build a small rate card from jobs you have observed or completed, separating cutting in, rolling, spray application, and trim. When answering an estimating question, break the job into these task types, apply a rate to each, then add drying and access time before totalling.
When asked about spraying, the candidate describes gun operation without covering masking of adjacent surfaces, extraction and ventilation, or the overlap and distance technique that prevents runs and dry spray.
Spray equipment is often studied only as hardware, so candidates cannot connect setup, technique, and containment into one safe, quality-controlled process.
What to do instead
Write a one-page spray procedure covering containment and masking, extraction, product thinning to the stated viscosity, gun distance and overlap, test pattern on scrap, and cleaning of equipment. Answer scenario questions by walking through this procedure in order.
The candidate describes working at height or erecting access equipment without naming the pre-use check, the load rating, or the fall-protection measure required for the specific task.
Access and height content is treated as general awareness rather than as a task-specific hazard assessment, so candidates give broad answers that miss the decisive control.
What to do instead
For ladders, mobile scaffolds, and elevated work platforms, write the pre-use inspection items, the load and height limits, and the fall-protection or exclusion-zone control. Practise answering by stating the task, the equipment, the check, and the control in that order.
The candidate answers environmental and waste questions by saying materials were disposed of responsibly, without naming segregation of solvent waste, bunding or spill containment, or the correct route for liquid and container waste.
Environmental duty is often memorised as a value statement rather than as concrete procedures, so candidates cannot specify what happens to thinners, empty containers, or washout water.
What to do instead
Write a waste map for a typical job: what is segregated, what container is used, where it is stored, and who removes it. Include spill kit location and bunding for decanting. Answer questions by naming the waste stream first, then the handling method, then the disposal route.