Sorry disagree. You should have dedicated "for purpose" electrical/ electronics solder in the proper ratio and with proper flux, whether you have additional flux, or not. And you should not use 50/50 on electrical. Kester used to "may still" market what they called 40/60 "radio" solder, which is just exactly what you need
I'm 70, and the first time I ever soldered anything I was about 12 or 13 years old
