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Corrosion on aluminium surfaces --- whether it involves aircraft, boats or automotive parts --- can be easily noticed. The corrosion appears as a white dust. Corrosion occurs when the surface has been exposed to oxidation and salts. Underneath the dust, the surface may look etched, pitted and have a general roughness. Corrosion around rivets and seams cause a weakening in the joint structures. Treating corrosion on aluminium will differ in its severity. The key lies with the proper methods and chemicals.
Mix a solution of mild dish soap and water in a bucket. Dip a stiff-bristle brush into the solution and remove all oil, dirt and grease. Remove all heavy, white encrustation with the brush and rinse thoroughly. Dry the surface with a clean towel. Apply a non-abrasive paste wax to the surface. Let it dry and remove the wax film with a clean towel.
Remove medium corrosion on plated or alloy aluminium by scrubbing the part with a brush and dish-soap solution. Remove all oil, grease and dirt. Rinse the part with water and dry with a towel. Scrub the area with a scouring pad and aluminium compound polish, using circular motions. Remove the pits and etching with the scrub pad. Polish the residue with a towel until the part is clean and shiny. Apply a non-abrasive wax and wipe the wax residue off with a towel.
Wash the part with a stiff-bristle brush and dish soap to remove grease, oil and white oxidation for a heavy encrustation. Rinse with water and dry with a towel. Put on gloves, particle mask and safety goggles. Mix a 10-percent solution (equal parts) of chromic and sulphuric acid in a coffee can filled with water.
Dip a stiff-bristle brush in the acid solution and scrub the part, working the bristles into the etching and pitted surfaces. Allow the acid solution to remain on the surface for at least 5 minutes, then scrub again. Rinse thoroughly with water. Dry the surface with a towel. Scrub the surface with a scouring pad and fine aluminium compound polish, using circular motions. Wipe the compound residue dry with a towel. Apply a coat of non-abrasive wax and buff it dry with a clean towel.
Clean a painted aluminium surface using the same technique as in Steps 3 and 4. Prepare surfaces that will be painted in the same manner, except do not apply a wax coat. Paint the surface immediately after cleaning because oxidation will form instantly. After the paint has dried and cured, apply your protective wax coat and buff it dry with a towel.
- Avoid cleaning solvents on aluminium that contain alkaline, fluoride and chlorine chemicals. These chemicals are too harsh and will cause additional etching and pitting in the metal surface. Scrub lightly on plated or filmed aluminium coverings.
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