Faults in Painting Plastics - Flaking

Definition

Easy removal of the total film build from the plastic substrate.

Causes

1] Insufficient cleaning of the plastic substrate.

2] Insufficient sanding of the plastic substrate.

3] Unsuitable cleaner or degreaser used, or wrongly used

4] Plastic part not tempered before painting.

5] No plastics primer/adhesion-promoter or 2C plastics primer filler used.

How to avoid

1] Wash the part thoroughly with a mild detergent solution to remove any water soluble release agents. Thoroughly clean the plastic with Glasurit Universal Cleaner 541-30 to remove solvent soluble release agents. Where plastic is very dirty or textured, clean with the assistance of a sanding pad. Clean the surface before and after sanding.

2] Use recommended sanding grades. Where an irregular shaped part is to be sanded (e.g. radiator grill, bumper etc.) use a sanding pad.

3] Re-clean with Glasurit Cleaner 541-30.

4] "Tempering” means sweating out the release agents by heating (1-2 hours at a maximum)

5] Use Glasurit 934-0 1C Plastics Adhesion Primer or Glasurit 934-10 1C Plastics Primer or Glasurit 934-70 2C Plastics Primer Filler as per Refinishing Systems S. 3 / S. 3a.

Repair

Remove the flaking paintwork completely and refinish as per the Glasurit Finishing Process V3. Do not use a normal paint stripper or the plastic could be damaged or destroyed.