"Smitty Two" wrote in message
news
Soldering is easy if you know how, not if you don't. Surfaces must be
clean and shiny and the soldering iron tip must be clean and shiny with
a fresh tinning of solder. Liquid flux (non-corrosive electronics flux)
is essential to de-oxidize the surfaces and help the solder to flow. The
amount of flux in "flux-cored" solder is insufficient.

I've rarely need other than flux core solder for electrical work.

Bob