On Fri, Nov 7, 2014 at 6:47 PM, James
bitsyboffin@... [Homebrew_PCBs]
<Homebrew_PCBs@yahoogroups.com> wrote:
Put some gel flux (or liquid, but I prefer gel/paste from a syringe) down on the bare pads which you have previously cleaned with whatever solvent you prefer, align the IC, solder down a pin on one corner to tack it in place, then just drag along the pins with your iron that has been pre-loaded with some solder, or you might prefer to "stroke" away from the pins, or use iron and solder together.
As James says.
Flux removes existing oxides. Flux prevents oxidation during soldering. Flux helps distribute heat. As well as removing oxides, flux also changes surface tension, helping the solder wet the leads and pads, and making it far less likely that you'll get bridges.
Flux is the answer. Flux is your friend.
Here's a video of John Gammell in action. The flux goes on at 1:57. It's already there at 0:56. Also note at 1:20, he's heating the pad rather than the pin, and note at 1:35 how long the pads are.
Sigh. I don't think I could ever get tired of watching this video, but maybe that's just me.
Mitch.