From the JB Weld website:
"DRYING: Allow 4-6 hours for drying before handling. Allow to dry overnight (approximately 15 hours) before putting object to use. J-B WELD works faster if used in a room with a temperature above 50� F. After J-B WELD has cured for six hours, a heat lamp or light bulb placed near the weld will speed drying time."
I didnt have a heat lamp, per se, last time I use JB Weld so I used one of those single halogen work lamps and put it about 6 inches from the project...warmed it right up.