Reddit reviews Solder Flux, Liquid 2oz - 10-4202

If you need to solder on a pcb you'll want a temperature controlled soldering station, other essentials are rosin core solder, some flux to apply before soldering, and a helping hand to hold the pcb/component and wire in place when soldering. I leave my soldering station at a little less than 350 when I'm tinning wires and soldering on a pcb. Wipe excess solder off the iron, heat up the spot you want to solder to with the wire in place, then apply solder to the wire when the flux has smoked off, it should flow into the joint. You don't want to keep heat on a pcb for too long as it can damage components on the board. Make sure you tin the tip/s of the soldering iron with solder before and often during use, or the tips will oxidize and refuse to tin until you scrape the oxides off with a razor knife. Typically a problem at high temps, around 300C solder will melt and oxides form very slowly and the tip will stay hot without needing a retin for a 5-10 minutes. I usually set my temp on max when I first turn it on and hold a bit of solder to the tip and then turn it down when the solder melts. Saves a few minutes of warm up between use.

If you need to heat up a larger surface area (like a battery terminal) for tinning or soldering it helps to bump up the heat - sanding a large surface also will help. Steel and other metals may require use of a corrosive flux made specially for that.

That's about all I know XD