After cleaning aluminum to remove corrosion, what is applied to protect the surface?

• A. Oil coating.
• B. A coat of wax.
• C. A coat of paint.
• D. Sealant only.

Answer: (C)

After removing corrosion from aluminum, you restore a protective barrier by applying paint. A paint system provides a durable, continuous film that seals the surface from moisture, oxygen, and chemicals that cause corrosion. When properly applied, it often includes a primer to improve adhesion and corrosion resistance, followed by the topcoat.

Oil or wax coatings are temporary and offer limited protection; they can attract dirt and degrade quickly in an aircraft environment. Sealant alone isn’t used as a full surface coating for aluminum—it's mainly for sealing joints and seams, not for protecting a bare metal surface. Paint, with the appropriate primer and topcoat, is the standard protection for exposed aluminum surfaces after corrosion removal.