Common Paint Problems

How-To

Detailed solutions from PPG Porter® to the most common paint problems faced by both painting professionals and do-it-yourselfers.

Exterior

Alligatoring:

Patterned cracking in the surface of the paint film resembling the scales of an alligator.

Possible Causes

  • * Application of an extremely rigid coating, like an alkyd enamel, over a more flexible coating, like a latex primer
  • * Application of a top coat before the undercoat is dry
  • * Natural aging of oil-based paints as temperatures fluctuate. The constant expansion and contraction results in a loss of paint film elasticity.

Solutions

Old paint should be completely removed by scraping and sanding the surface. A heat gun can be used to speed up work on large surfaces, but take care to avoid igniting paint or substrate. The surface should be primed with a high-quality latex or oil-based primer, and then painted with a top-quality exterior latex paint.

Porter® System Recommendations

  • Primer: One Coat of ACRI-SHIELD Acrylic Bonding Primer No. 515
  • Finish: One or more coats of Super Premium ACRI-SHIELD Acrylic Finish No. 519 Flat, 739 Satin, 619 Gloss
  • Or:
  • One or more coats of ACRI-PRO 100 Acrylic Finish No. 929 Flat, 3729 Satin, or 6029 Semi-Gloss