Extra heat keeps degrading the film after cure is complete. Whites and pastels yellow first, gloss drops, colors shift, and impact and flexibility fall off. Overbake tolerance is often specified as color change after a set multiple of the cure time or a set temperature above the cure point. Line stoppages with parts in the oven are the usual cause.
Line stopped for half an hour with the white in the oven, those parts are overbaked and yellow.
Also heard as
- overcure
- overbaked
Do not mix it up with
- Undercure: Undercure is not enough heat; the film looks fine but lacks hardness and solvent resistance.
Related terms
Undercure
A film that did not get enough time at temperature to crosslink fully, so it looks fine but performs poorly.
Yellowing
A yellow shift in whites and light colors caused by overbake or by fumes in gas-fired ovens.
Cook
Line slang for curing parts in the oven, and in the past tense, for parts that got too much heat.
Cure schedule
The time at temperature a powder needs to cure fully, measured at the part's metal, not the oven air.