Post Cure

Understanding

Determining

Executing

Guidelines

Heating Methods

Post-Curing in Moulds

Achieving optimal physical properties in your epoxy components often requires post-curing – controlled heating after the initial cure stage. Let’s delve into the specifics:

Understanding Post-Curing

Certain resin/hardener combinations, such as LAM-249-HT, INF-249-HT, LAM-239 and HTP variants, require an elevated-temperature post-cure for peak performance. Post-curing enhances physical strength and thermal properties beyond what’s achievable with room-temperature cures alone.

Determining Post-Cure Schedules

Each resin/hardener combination has unique post-cure requirements to unlock 100% of its potential properties. Published properties won’t be reached if post-cure temperatures fall below specified levels. Establish post-cure schedules based on desired physical properties, equipment limitations, and material tolerances.

Executing Post-Cure

During post-cure, gradually raise the part’s temperature to the target, hold it, and then slowly cool it. To avoid thermal shock, increase temperatures gradually and don’t exceed maximum thresholds. The post-cure schedule dictates the maximum potential properties achievable.

Recommended Post-Cure Guidelines

Follow these guidelines for optimal post-curing:

PRO-SET^® Laminating and Infusion Epoxies

• Increase the temperature from room temperature by 8°–11°C (15°–20°F) per hour.
• At every 22°C (40°F) increase in temperature, hold that temperature for an extra hour to allow internal laminate temperatures to equalise. Resume the temperature increase of 8°–11°C (15°–20°F ) per hour.
• Continue this cycle until the post-cure temperature is reached.
• Hold the temperature as indicated on the resin/hardener data sheet.
• Decrease the temperature at a rate of 11°C  (20°F) per hour.
• Hold at 35°C (95°F) for two hours to allow for normalisation.
• Turn off heat and allow to cool to room temperature. This schedule is recommended when curing a lighter laminate. The temperature ramp speed should be decreased for moulds, plugs, and heavy laminates. We recommend building test panels of the finished laminate schedule to determine the ideal post-cure cycle. Thermocouple wires embedded in the test laminate will measure the temperature lag during the post-cure.

PRO-SET^® High-Temperature Epoxies

• Increase the temperature from room temperature at a rate of 12°F (7°C) per hour.
• Hold at 140°F (60°C) for 2 hours to allow internal laminate temperatures to equalize. Resume the temperature increase of 12°F (7°C) per hour.
• Hold the temperature as indicated on the resin/hardener data sheet [275°F (135°C)].
• Decrease the temperature at less than 20°F (11°C) per hour.
• Hold at 95°F (35°C) for two hours to allow for normalization.
• Turn off heat and allow to cool at room temperature. The schedule is recommended for curing a lighter laminate. The temperature ramp speed should be decreased for molds, plugs, and heavy laminates. We recommend building test panels for the finished laminate schedule to determine the ideal post-cure cycle. Thermocouple wires embedded in the test laminate will measure the temperature lag during post-cure.

Heating Methods

Various heating methods are available, from insulated ovens to radiant heaters. However, radiant heating may lead to uneven curing and laminate print-through, so caution is advised.

Post-Curing in Moulds

Moulds should be post-cured at temperatures exceeding those required for finished parts to prevent distortion. Similarly, plugs used in mould construction should be post-cured at higher temperatures to maintain fairness.

Adhering to these guidelines and considering specific resin/hardener combinations can achieve optimal post-cure results, ensuring the highest quality in your epoxy components. Consult the respective Technical Data Sheets for detailed instructions tailored to your products.