Which statement correctly matches removal methods to aluminium alloys?

Which statement correctly matches removal methods to aluminium alloys?

• A. Clad aluminium: Chemical removal; non-clad aluminium: Mechanical removal
• B. Clad aluminium: Mechanical removal; non-clad aluminium: Chemical removal
• C. Clad aluminium: Wipe with oily cloth; non-clad aluminium: Prepsol
• D. All aluminium alloys: Chemical removal

Answer: (A)

Preserving the protective cladding on aluminum is essential in aviation surface work. Clad aluminum has a thin outer layer of pure aluminum bonded to the core alloy to resist corrosion. When removing coatings or corrosion products, you want to avoid wearing away that thin protective layer. Chemical removal is preferred for clad aluminum because it dissolves or softens the coatings without the abrasive wear that could remove or thin the cladding. This keeps the protective outer layer intact while the coating is removed. In contrast, non-clad aluminum has no outer protective layer, so mechanical removal can be used more freely to strip coatings or corrosion products without the same risk of exposing a vulnerable core. Degreasing steps like wiping with an oily cloth or using a solvent such as Prepsol are useful prep actions, but they don’t define the removal method itself. The key idea is that clad aluminum uses chemical removal to protect the cladding, while non-clad aluminum allows mechanical removal.

Preserving the protective cladding on aluminum is essential in aviation surface work. Clad aluminum has a thin outer layer of pure aluminum bonded to the core alloy to resist corrosion. When removing coatings or corrosion products, you want to avoid wearing away that thin protective layer.

Chemical removal is preferred for clad aluminum because it dissolves or softens the coatings without the abrasive wear that could remove or thin the cladding. This keeps the protective outer layer intact while the coating is removed. In contrast, non-clad aluminum has no outer protective layer, so mechanical removal can be used more freely to strip coatings or corrosion products without the same risk of exposing a vulnerable core.

Degreasing steps like wiping with an oily cloth or using a solvent such as Prepsol are useful prep actions, but they don’t define the removal method itself. The key idea is that clad aluminum uses chemical removal to protect the cladding, while non-clad aluminum allows mechanical removal.