I've just cured my first prepreg part and it still feels slightly flexible and rubbery. It isn't sticky, but it's not as rigid as I expected. Is this normal?
A prepreg laminate should feel fully cured and rigid once the recommended cure cycle has finished, so a soft or rubbery part usually points to one of three things: the cure temperature was not reached, the cure time was too short, or the prepreg had gone past its allowable out-life before curing. It is also worth checking that the temperature you measured during the cure was the part itself rather than just the air in the oven. A thermocouple attached to the laminate gives a far more accurate reading of the actual cure temperature.
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