Reasons could be: Low temperature, Off-ratio mixing, Insufficient mixing, High humidity, Incorrect resin or hardener, Incorrect product for that specific project.
Off-Ratio Mixing: If your ratio’s are even slightly off, by either adding too much or too little hardener this will result in affecting the cure time of the batch or having it cure at all.
High Humidity Levels: High humidity levels over 75% can also cause product curing issues.
Incorrect resin or hardener: Using different lines of our products together can definitely cause under curing or overreacting resins.
Insufficient mixing: Always mix thoroughly with a drill and slow speed mixer for at least 3-4 minutes. You may not have mixed long enough for the resin and hardener to properly mix together