09
Coating
Chalking
A dull, chalky deposit on the paint surface — degradation of the resins in the clear coat under the effect of UV and poor protection of the finish.
Cause
- Prolonged exposure of the resins in the clear coat layer to UV radiation — gradual breakdown of the coating structure
- Use of a clear coat without a UV filter or with insufficient protection against sunlight
- Wrong choice of hardener — too little or too much causes incomplete cross-linking and lower UV resistance
- Incorrect thinner ratio — over-thinned clear coat has a lower resin density and degrades faster
- Washing the car with aggressive cleaning agents which destroy the protective layer
- Lack of regular waxing — wax creates an additional barrier against UV and slows down chalking
- Parking exclusively in the sun without any protection for many years
Prevention
- Use clear coats with high resistance to UV radiation
- Observe the hardener and thinner mixing ratios from the technical data sheet
- Advise the owner to wax regularly — at least twice a year
- Avoid aggressive cleaning agents and coarse polishing compounds
- Use only cleaning agents designed for automotive paintwork
Repair
- Light chalking — polish the surface with a fine polishing compound, then protect it with wax
- Protective wax temporarily restores the appearance but is not a permanent solution
- Deep chalking — sand off the degraded clear coat layer and apply a new one with adequate UV protection
- After the repair, advise the owner to protect the paintwork regularly every 6 months