Painting and Detailing
Domain focus
Painting and Detailing tests surface preparation, masking, primer, basecoat, clearcoat, spray technique, defect correction, and safe detailing. Expect cause-and-effect questions on runs, orange peel, and adhesion failure.
Core rules
- Preparation determines finish: wash, degrease, sand, repair, prime, and sand primer before topcoat. Wax and silicone cause fish eyes.
- Mask glass, trim, and openings; use tack cloth before painting. Maintain recommended flash time between coats.
- Spray gun distance, speed, fluid flow, and air pressure affect atomisation. Too close or too slow causes runs; too dry causes orange peel.
- Use booth ventilation and respiratory protection. Clearcoat protects basecoat and gives gloss. Clean the gun after use.
- Detail with pH-neutral shampoo, microfibre cloths, and polishes appropriate to the finish.
Worked example
A fresh clearcoat shows a run on a vertical panel. The likely causes are too heavy a coat, gun too close, or too slow a pass. The reasoning is that excess wet film cannot hold its shape. Allow curing, sand level carefully, and recoat with thinner passes.
Traps
Painting over silicone, skipping flash time, sanding through edges, and polishing before full cure are common mark losers.