Definition
A slow-evaporating thinner added to nitrocellulose or other lacquer-based aircraft finishes to prevent blushing — a milky white or cloudy haze that forms in the finish when it is sprayed in humid conditions.
Plain English
A special paint thinner used when spraying lacquer in damp weather. It slows down how fast the paint dries so moisture in the air does not get trapped in the finish and turn it cloudy white.
Context Anchor
Seen in aircraft painting, fabric covering, and refinishing work, especially when lacquer or dope is being sprayed in damp conditions.
Derivation
‘Blush’ here borrows from the everyday meaning of skin turning a different colour. When lacquer dries too fast in humid air, moisture gets trapped and the surface turns a pale, cloudy white — it ‘blushes’. ‘Antiblush’ simply means it prevents that effect.
Why Pilots Care
Mostly relevant to owners, mechanics, and restorers of older or fabric-covered aircraft. Using the right thinner for the conditions is the difference between a clean, glossy finish and one that has to be stripped and redone.
Grounding Statement
In humid weather, antiblush thinner helps the finish dry slowly enough that moisture does not get trapped and turn the surface cloudy.
Intuition Check
Do not read “blush” here as a red color or a cosmetic term. In aircraft finishing, blush means a cloudy white haze in the dried coating.
Example Sentence 1
Because we were spraying the wing in humid weather, the painter mixed antiblush thinner into the lacquer to keep the finish from clouding.
Example Sentence 2
Without antiblush thinner the new paint on the fuselage developed a white haze overnight.