To remove surface corrosion from aluminum and prevent further damage, which sequence is recommended?

• A. Remove corrosion residue with a bristle brush or nylon scrubber; neutralize with chromic acid or conversion coating; protect with paint.
• B. Soak in strong acid until fizzing stops; then wax.
• C. Use steel wool aggressively and rinse with water.
• D. Apply oil-based sealant and ignore cleaning residue.

Answer: (A)

When protecting aluminum from surface corrosion, the first priority is to clean and prepare the surface so the protective coating can adhere and do its job. Start by removing the corrosion residue with a bristle brush or a nylon scrubber. This physically clears away oxides and loose particles without scratching the metal or embedding abrasive material that could worsen damage.

Next, treat the cleaned surface to form a stable, protective film. Neutralizing with chromic acid or applying a conversion coating changes the surface chemistry to a more corrosion-resistant layer, reducing reactivity and improving adhesion for a subsequent coating.

Finally, apply a protective paint or coating to seal the surface from moisture and environmental contaminants, preventing future corrosion.

Why the other options aren’t suitable: soaking in strong acid can aggressively damage the aluminum and create pits; wax offers little to no durable protection for structural aluminum surfaces; using steel wool risks embedding particles and creating scratch lines that accelerate corrosion; and applying an oil-based sealant without proper cleaning leaves residues and moisture trapped under the coating, which undermines adhesion and protection.