Cleaning & Corrosion Control
Why must painted surfaces be inspected often for blisters, flakes, chips, and lumps?
Answer
Paint can mask the initial stages of corrosion, and corrosion products occupy more volume than the original metal
The handbook warns that paint can mask the initial stages of corrosion, and because corrosion products occupy more volume than the original metal, the underlying attack pushes the finish up into irregularities. Blisters, flakes, chips, and lumps in a finish are therefore the visible signals a technician uses to find corrosion that is hidden under the coating.
Source: FAA-H-8083-30B, Ch. 8 p. 8-3 — 'Corrosion — NOTE on painted surfaces'
Not the answer
- Paint flakes are the only permitted evidence that a conversion coating has failed
- Paint chemically accelerates corrosion of the metal beneath it
- Blisters and lumps always indicate that the paint was applied too thickly
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