Definition
A mass of fine, hair-like steel fibers bundled together, used as a mild abrasive and cleaning material. In aircraft maintenance, steel wool is graded by coarseness (from coarse to extra fine) and used for tasks such as cleaning metal surfaces, removing light corrosion, and polishing. It must be used with caution on aluminum and other non-ferrous metals because embedded steel particles can promote corrosion.
Plain English
A pad of fine steel threads used like sandpaper to clean, scrub, or polish metal surfaces.
Context Anchor
Seen in aircraft maintenance, surface preparation, cleaning, and corrosion-control discussions.
Derivation
“Steel” means the material the fibers are made from. “Wool” is used because the fine metal strands look and feel like a loose bundle of fibers, not because it is animal wool.
Why Pilots Care
Improper use of steel wool on aluminum aircraft skin or parts can leave embedded steel particles that cause galvanic corrosion later. Mechanics and owners performing minor cleaning need to know when steel wool is appropriate and when a non-ferrous alternative (like aluminum wool or a Scotch-Brite pad) should be used instead.
Intuition Check
Do not think of steel wool as just a household cleaning pad. On an aircraft, the loose metal fibers it sheds matter, so its use must be controlled.
Example Sentence 1
The mechanic used fine steel wool to clean light surface rust from the steel engine mount before applying primer.
Example Sentence 2
After sanding, the mechanic wiped the surface clean to ensure no steel wool fibers remained that could cause future corrosion.