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Composite Fabricating Basics Step 4: Proper Curing

STEP FOUR: PROPER CURING

Allow the lay-up to cure for a minimum of 24 to 36  hours before handling.Optimum cured properties can take up to 7 days depending on the ambient cure condition. The ideal temperature cure condition of most room temperature epoxy resin is 22 to 27 degrees Celsius at 20% relative humidity. Higher ambient curing temperatures will promote faster polymerization and development of cured mechanical properties.

Improving mechanical performance via post heat cure
A short heat post cure will further improve the mechanical performance of most epoxy resins. Allow the applied resin system to cure at room temperature until for 18 to 24 hours and if possible, expose heat cure it in an oven  or other source of radiant heat (220°F to 250°F) for 45 minute to an hour. You can also expose it to direct sunlight but place a dark colored cover, such as a tarp or cardboard to protect it from ultraviolet exposure.
In general room temperature cured epoxy resin has a maximum operating temperature of 160°F or lower.
A short heat post cure will ensure that the mixed epoxy system is fully cured,especially for room temperature cured system that can take up to 7 days to achieve 100% cure. Some darkening or yellowing may occur if overexposed to high temperature (>250 F).
Amine Blush

Other Types of Epoxy Resin Curing Mechanisms

Latent Curing Systems
UV Curing Systems
Heat Activated Curing Systems

 

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