Use liquid soldering flux?

Got myself some new cables and connectors. I've done flimsy soldering on my old junk cables in the past, but I want these ones to be done right.

Watched some Youtube videos. In one of them the guy puts a drop of solder flux before tinning the wires. But I've got some 60/40 rosin core solder, so do I still need it?

I also think the hardware store guy screwed up when he helped me find the liquid soldering flux. It says it's an acid flux for non-electrical applications. Wrong stuff?

Rosin core solder is fine. Theres no need to use additional flux.

You need to beware, if you ever did use flux, you need to use flux designed for electronics. Never ever use flux designed for plummers. Plummers flux is highly corrosive and will eat through thin wires and PCB traces. Plumbers use Solid core solder and an acid based flux to solder pipes. The flux will eat through heavy copper pipe oxidation and is designed to be used with a propane tourch.

Here's a link to my local electronics store that carries the proper kind of flux for electronics. As you can see, it's a clear amber liquid. Don't use plumbing flux or plumbing solder for electronics, ever.

http://www.altex.com/GC-Liquid-Solder-Flux-2-oz-10-4202-P139823.aspx

Most of the time it's not necessary, the flux in rosin core solder is enough for most circumstances. Times when the liquid flux does help are soldering on pots or battery tabs. I've never used it for soldering connectors on cables.

Rat Shack has a perfectly good paste flux. I only use it if I'm soldering an old part that may have a bit of corrosion.

BTW Rat Shack used to sell cheap junque soldering irons. Guess what? They've gone Weller on us.

I like paste flux, myself.