Definition
A petroleum-based cleaning solvent with a flash point of approximately 100 to 110 °F, widely used in aviation maintenance to remove grease, oil, dirt, and soft preservatives from aircraft parts and structures. It is less volatile and less hazardous than gasoline or naphtha but still flammable and must be used with proper ventilation and fire precautions.
Plain English
A mild, oil-based cleaning fluid that mechanics use to wash grease and grime off aircraft parts. It works better than soap and water for oily mess, and it is safer to handle than stronger solvents like gasoline — but it can still catch fire if handled carelessly.
Context Anchor
Seen in aircraft maintenance cleaning procedures, especially when removing grease or oil from metal parts before inspection, repair, or reassembly.
Derivation
Named after W. J. Stoddard, an American dry-cleaning industry figure who, in the 1920s, helped develop a safer petroleum cleaning fluid to replace the highly flammable solvents then in use. Knowing the name is a person's name (not a chemical description) helps explain why the term gives no clue about what is in it.
Why Pilots Care
Proper cleaning with this solvent prevents corrosion and contamination that could affect structural integrity or system function.
Intuition Check
Do not assume “solvent” means any general cleaner. Stoddard solvent is a specific petroleum-based cleaner, and its flammability matters during aircraft maintenance.
Example Sentence 1
Before reinstalling the landing gear bushings, the technician wiped each part down with Stoddard solvent to remove the old grease.
Example Sentence 2
Stoddard solvent was applied to the wing spar fittings during the annual inspection to ensure all grease was cleared.