Qualitek sn100e solder wire with nc601e rosin free no clean flux qualitek nc601e sn100 020w a flux cored solder wire made from sn100e a lead free alloy consisting of 995 tin 05 copper and a trace of cobalt the nc601e flux is a colophony free no clean type that leaves virtually no post soldering residue for a visibly clean solder connection qualitek solder wire sn100e nc601 rosin free no clean flux 22 051mm 500g reel