Definition
A second heat-treatment step applied to a resin or composite part after its initial cure, used to complete the cross-linking of the resin and bring the material to its full strength, stiffness, and heat resistance.
Plain English
After a resin part has hardened, it is heated again for a set time so the chemistry inside can finish locking together, making the part as strong and heat-tolerant as it is meant to be.
Context Anchor
Seen in composite aircraft repair and maintenance instructions, especially when a repaired part must be heated for a set time after the first hardening step.
Derivation
‘Post’ comes from Latin meaning ‘after,’ and ‘cure’ in materials work means to harden a resin through a chemical reaction. So ‘post cure’ literally means ‘after the cure’ — a second hardening stage that follows the first.
Why Pilots Care
A composite part that has not been properly post-cured may look finished but will not reach its rated strength or temperature limits, which matters for repairs to cowlings, fairings, control surfaces, and structural composite components.
Intuition Check
Post cure does not mean fixing a defect after something went wrong. It means a planned final hardening step after the material has already partly or fully hardened.
Example Sentence 1
After the initial layup hardened overnight, the technician placed the cowling repair in the oven for the manufacturer’s specified post cure.
Example Sentence 2
Skipping the post cure left the composite part with reduced strength and a lower glass transition temperature.