Which sequence correctly describes recommended surface preparation for aluminum prior to welding?

• A. Thorough cleaning to remove oxide with a stainless steel brush or cleaner, followed by solvent wiping; ensure dry and free of contaminants.
• B. Rinse with water only and air dry.
• C. No cleaning is required.
• D. Wipe with oil to prevent oxidation.

Answer: (A)

Aluminum welding requires a surface free of oxide and contaminants because the natural oxide layer and oils on the surface prevent proper fusion and can cause porosity. The best preparation is to thoroughly clean the aluminum to remove the oxide film with a stainless steel brush or an approved aluminum cleaner, then wipe with a solvent to remove oils and greases, and finally ensure the surface is completely dry and clean. If you rinse with water only, or skip cleaning, the oxide and moisture remain and can compromise weld integrity. Wiping with oil leaves hydrocarbons on the surface, which also contaminates the weld. So this combination—oxide removal, careful cleaning, solvent wipe, and drying—provides a clean, metal-to-metal surface ready for welding.