Reactive adhesives cure by crosslinking, triggered by mixing two parts, moisture, heat, light, absence of oxygen or surface chemistry. Non-reactive ones harden by losing water or solvent or by cooling. Engineers separate fixture, handling and full cure because strength keeps rising for hours or days after a part can be moved. Temperature speeds or slows nearly every cure, roughly doubling the rate for each 10 C rise.
Parts can move after an hour, but no load testing until full cure, that's 24 hours at room temp.
Cold shops slow cures drastically; a room-temperature epoxy rated for 24 hours at 23 C takes several days at 10 C.
Also heard as
- curing
Do not mix it up with
- Set up: Setting up describes the early thickening and grab, while cure covers the whole reaction to final properties.
Related terms
Fixture time
The time until a bond is strong enough to handle or unclamp the assembly without moving the parts.
Post-cure
Extra time at elevated temperature after the first cure, which finishes crosslinking and raises Tg and heat resistance.
Moisture cure
A cure triggered by humidity in the air or on the parts, used by silicones, urethanes and silane polymers.
Set up
To thicken and start to hold, the point where an adhesive stops being workable.