Yes it has a 2% flux content. Had tried lead-free solder on the Gretsch (previous kit) but found it harder to melt, so returned to the lead content for this one. Regarding irons, I first started kit no. 1 in 2010 with a 25 watt, then moved up to a 40 watt and more recently reached an 80 watt iron which actually tripped my house RCD! So I've gone back to the 40 watt iron and this (with my flux 'trick') seems to work as is supposed. Never been my forte. But I'm more than thrilled with current progress. Yes I've watched all the videos on soldering and they make it look so easy - one touch of the iron and hey presto - but that has never been the case with mine. Have read about oxidisation etc but to no avail. Onwards and upwards!