•How high should I take my maximum topside temperature during preheat?
–It is optimal to take most VOC-free fluxes up to 105-120°C (220-250°F). Temperatures below this will likely result in spattering and temperatures above this can prematurely volatilize the activators, causing bridging defects.
–In the ideal profile, you would heat the board at 2°C/second (3.5°F) to 110°C (230°F) and then maintain that temperature throughout preheat.