Once you have the exact amounts of resin and hardener in your mixing pot, stir them for at least 2-3 minutes (longer for larger volumes). It's important that all the molecules are mixed thoroughly so you get a proper cure. While stirring, the most important thing is to be sure to scrape the bottom and sides of the cup in order to mix both components completely. Most issues with improper cure are due to incomplete mixing of the two components.
To ensure the best possible mix, we recommend the two-cup method. This involves stirring the resin and hardener thoroughly in one cup for 2-3 minutes (while scraping the sides and bottom), then pouring the mixture into another cup and mixing thoroughly for an additional 1-2 minutes.