I've completed several end pours outdoors in the dead of winter here in Rhode Island by wrapping the end in an old horse blanket with a pair of light bulbs. Once the epoxy has started to feel warm on the outside, I turn off the light bulbs. The actual temperature came up to 150 deg. when I checked it with an IR temperature gage. It only took about 1 1/2 hours before I was able to flip it over and complete the other end. These were done with both MAS and System 3.

: Place the end in a bucket of hot water. This will make the epoxy warm enough
: despite the outside temperature while also assuring it doesn't get too
: hot. Just be sure that there are no leaks in the end of the boat.