A galvanized surface has been damaged. The contractor wire brushes the surface to remove the cracked coating, and then used spray paint to apply unthinned zinc rich paint to the cleaned areas. The contractor proceeded:

A galvanized surface has been damaged. The contractor wire brushes the surface to remove the cracked coating, and then used spray paint to apply unthinned zinc rich paint to the cleaned areas. The contractor proceeded:

• A. Correctly
• B. Incorrectly, he should have not used a wire brush
• C. Incorrectly, he should have not used spray paint
• D. Incorrectly, he should have thinned the paint

Answer: (C)

Repairing damaged galvanized coating requires applying zinc-rich coating to clean metal with a method that builds a proper, continuous film. After removing the cracked coating, you’ve exposed bare zinc that needs to be rebuilt with zinc-rich material so the protective, sacrificial layer can continue to protect the metal. Brushing or rolling on zinc-rich coating ensures the coating adheres well, reaches the necessary film thickness, and can be worked into edges and crevices. Spraying zinc-rich paint is not appropriate here because it can cause uneven coverage, insufficient zinc deposition, and overspray, leaving areas inadequately protected. So the contractor should have applied the zinc-rich coating by brush or roller rather than spray, following the recommended film thickness and cure guidelines.

Repairing damaged galvanized coating requires applying zinc-rich coating to clean metal with a method that builds a proper, continuous film. After removing the cracked coating, you’ve exposed bare zinc that needs to be rebuilt with zinc-rich material so the protective, sacrificial layer can continue to protect the metal. Brushing or rolling on zinc-rich coating ensures the coating adheres well, reaches the necessary film thickness, and can be worked into edges and crevices. Spraying zinc-rich paint is not appropriate here because it can cause uneven coverage, insufficient zinc deposition, and overspray, leaving areas inadequately protected. So the contractor should have applied the zinc-rich coating by brush or roller rather than spray, following the recommended film thickness and cure guidelines.