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

Nailhead Rusting:

Reddish-brown stains on the paint surface.

Possible Causes

  • * Non-galvanized iron nails have begun to rust, causing bleed-through to the top coat
  • * Non-galvanized iron nails have not been countersunk and filled over
  • * Galvanized nailheads have begun to rust after sanding or excessive weathering

Solutions

When painting new exterior construction where non-galvanized nails have been used, it is advisable to first countersink the nailheads, then caulk them with a top-quality, water-based all-acrylic or siliconized acrylic caulk. Each nailhead area should be spot-primed, then painted with a quality latex coating. When repainting exteriors where nailhead rusting has occurred, wash off rust stains, sand the nailheads, and follow the same surface preparation procedures as for new construction.

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