Cracking

Causes

1. Inappropriate paint system used on thermoplastic substrates (direct use of polyester body fillers/fillers, wash primers/synthetic resin products on TPA) which caused the TPA surface to soften.
2. Refinished paintwork insufficiently cured (too little or no hardener used).
3. Inappropriate paint system used:
   • Wash primer overcoated with polyester products.
   • Synthetic resin or nitro-cellulose paints overcoated too early.
4. Cracks on plastic parts:
   see chapter on "Faults in painting plastics".
5. Exposure to strong UV radiation, extreme temperature fluctuations.
6. Flash-off time too short in wet-on-wet process.
7. Total film build too high.

How to avoid

1. Apply a suitable paint system to the substrate.
2. Ensure correct hardener quantities.
3. Use correct paint system.
4. Plasticise materials (see chapter "Faults in painting plastics").
5. There are no complaints about "cracking" with regard to present Glasurit automotive refinish products.
6. Respect recommended flash-off times.
7. Check paint system and film thickness of old paintwork and sand down or strip down, if necessary.

Please note: For older car models, use refinishing processes for solvent-sensitive paintwork. Classic Car system S 1a.

Repair

Sand down to the "sound" layers. Refinish using the recommended undercoats and topcoats.