Congratulations! Are you getting course credit for building a kayak?

A couple of thoughts about your epoxy problem. First, having just switched brands and mix ratios, are you sure that you have the correct mix rations for the MAS (2:1)? Second, especially if you are using the slow cure hardener, even at 70 degrees it will take a long time to harden, probably overnight. Can you heat the affected area by building a tent over it and putting a lightbulb or two inside. Watch the fire hazard and see if you can get the temperature up for a prolonged period of time.

Mike Scarborough
Friendship Kayak