Definition
The common name for sodium hydroxide (NaOH), a strongly alkaline chemical compound used in aircraft maintenance for cleaning, paint stripping, and as the electrolyte in nickel-cadmium (Ni-Cad) batteries. It is highly corrosive to skin, eyes, aluminum, and many other aircraft materials.
Plain English
A powerful chemical used in aircraft cleaning and inside certain batteries. It burns skin and eats away at aluminum, so it must be handled with care.
Context Anchor
Seen in aircraft maintenance, shop safety, cleaning, paint removal, and chemical handling discussions.
Derivation
Caustic' comes from the Greek 'kaustikos,' meaning 'able to burn.' 'Soda' is an old chemistry term for sodium compounds. The name reflects what the substance does: it's a sodium-based chemical that burns whatever it touches.
Why Pilots Care
Effective cleaning prevents corrosion and contamination, but any residue left on aircraft parts can cause structural damage or safety hazards.
Grounding Statement
If caustic soda gets on skin, eyes, clothing, or the wrong aircraft surface, it can cause real chemical damage quickly.
Intuition Check
Do not confuse caustic soda with baking soda. Baking soda is mild; caustic soda is a strong, burn-causing chemical.
Example Sentence 1
The mechanic wore rubber gloves and a face shield when adding caustic soda electrolyte to the Ni-Cad battery.
Example Sentence 2
After cleaning with caustic soda, the parts were thoroughly rinsed and inspected to ensure no residue remained before reassembly.