If I'm using towerhobbies brand "30-minute" epoxy then once I mix it, how much time do I have before it becomes too sticky to use? Or how much time am I supposed to have to apply it and stick the parts together?

I know this seems like a dumb question, but I've mixed three batches so far while assembling my first ARF and it seems that I only have 15 minutes to use the mix before it becomes too sticky to apply or maneuver pieces into position. On the third batch I cooled the bottles down and it didn't seem to affect anything.