Definition
A liquid finish made from cellulose acetate butyrate dissolved in solvents, brushed or sprayed onto fabric-covered aircraft surfaces. As the solvents evaporate, the dope tightens the fabric, seals it against moisture, and forms a smooth base for protective and decorative finish coats.
Plain English
A paint-like coating used on fabric-covered aircraft. When applied to the cloth covering, it shrinks the fabric drum-tight, seals it, and gives a smooth surface for the final paint.
Context Anchor
Seen in aircraft fabric-covering, restoration, and maintenance discussions, especially on older or fabric-covered airplanes.
Derivation
‘Butyrate’ comes from butyric acid, which is used to make the cellulose acetate butyrate compound. ‘Dope’ is an old industrial word for a thick liquid applied as a coating. Together: a fabric coating based on butyrate chemistry.
Why Pilots Care
It keeps fabric coverings tight and airworthy on older aircraft, reducing the risk of tears or fuel damage that could affect flight safety.
Intuition Check
“Dope” does not mean a drug or a foolish person here. In aircraft covering, dope means a special liquid coating used to seal and protect fabric.
Example Sentence 1
After covering the wing with new fabric, the restorer brushed on several coats of butyrate dope to tighten and seal it.
Example Sentence 2
Many restorers choose butyrate dope because it resists fuel spills better than older nitrate types.