The cure rate for gelcoat is dictated by the temperature (ambient temperature, the product's temperature, as well as the substrate's temperature), and the amount of MEKP catalyst that has been added. Generally, gelcoat should get 1-3% MEKP catalyst, with 2% being the average. When mixing larger batches or working in warmer conditions, it is advised to reduce the percentage of catalyst as needed, down to 1%. When working with small batches or cooler temperatures, up to 3% catalyst can be added.
TotalBoat gelcoat without wax has the same cure time as gelcoat with wax.The gel time (similar to working time) is 8-12 minutes at 77°F, when 2% MEKP is added. Warmer conditions, or increasing the percentage of MEKP, will shorten the gel time. Cooler conditions, or using less catalyst, will extend the working time.
Gelcoat without wax can be recoated without sanding once it has cured to a firm, yet tacky state.