Definition
A colorless, volatile liquid solvent (chemical formula CH2Cl2) used in aircraft maintenance as the active ingredient in most aircraft paint strippers. It dissolves and lifts cured paint, primer, and other organic coatings from metal surfaces but must not be used on composite, fiberglass, or fabric structures because it attacks the resins and bonding agents.
Plain English
A strong chemical used to strip old paint off metal aircraft parts. It is harsh enough to soften paint quickly, which also makes it harmful to skin, lungs, and certain non-metal aircraft materials.
Context Anchor
Seen in aircraft maintenance, especially in discussions of paint stripping, cleaning chemicals, shop safety, and product safety labels.
Derivation
From 'methylene' (the chemical group CH2, derived from methyl, the simplest carbon-hydrogen group) and 'chloride' (a compound containing chlorine). The name simply describes its chemistry: a methylene group bonded to two chlorine atoms.
Why Pilots Care
It effectively removes paint but is toxic and can damage plastics or composites if misused.
Intuition Check
Do not assume methylene chloride is just another shop cleaner. It is a powerful solvent with fumes that can harm you if you breathe them.
Example Sentence 1
Before stripping the wing skins, the mechanic confirmed they were aluminum, since the methylene chloride remover would have damaged any composite panels.
Example Sentence 2
Protective gloves and ventilation are required when handling methylene chloride in the shop.