... you may get a solder blob. 3.Select flux core or no core. All solder joints need flux, which can be ... applied from a tube, with a brush, from the core of the solder or in any combination, depending on your ... application, but to be safe, always use a flux core so that you don’t forget. Solder sometimes in is ... with much lower melting points are available super sofa high quality pure tin soldering wire