Old Solder
in [Repair]
|
From: Jeffrey D Angus on 11 Jul 2010 14:39 Smitty Two wrote: > So don't take my word for it. Go to any manufacturing > facility that does any hand soldering, and you'll find > a little bottle of flux at every workstation. Try it > yourself and you'll see why. Oh yeah, I keep one on each active bench here. Jeff -- �Egotism is the anesthetic that dulls the pain of stupidity.� Frank Leahy, Head coach, Notre Dame 1941-1954 http://www.stay-connect.com
From: Jeff Liebermann on 11 Jul 2010 16:20 On Sun, 11 Jul 2010 10:46:33 -0700, Smitty Two <prestwhich(a)earthlink.net> wrote: >What you may have been missing is the speed, ease, and quality of >soldering with liquid flux vs. relying solely on the resin core. (...) Nice list. I've been soldering for about 50 years and only recently have started to use bottled flux. I quickly tin both ends of whatever I'm soldering first. That leaves a little flux on each end. If done correctly, I haven't found the need for liquid flux for large components. Tinning and intentionally leaving flux on the components requires more skill than is commonly available and isn't suitable for tiny components. I've recently been dealing with badly reflow soldered BGA chips, usually inside laptops. The trick is to reflow the solder bumps (usually with a hot air gun) without moving anything. Without a wetting agent (flux), the solder bump and PCB solder pad will not reflow together. Getting the flux to flow under the BGA is a major problem. My current method is to use a bent needle syringe, but that only works for small BGA's. Spraying with an atomizer and air hose works well, but also makes a huge mess. For soldering big heavy lugs and cables, flux is also required. The small amount of flux (about 5%) found in common solder is insufficient. By the time the solder melts and flows into the wire, all the flux has been burned off. The only choice is to add more flux. To avoid the drippy mess, I use rosin paste flux for lugs and cables. Another headache is mixing leaded and unleaded solder. I have separate irons and solder rolls for each. I can mix solder types and get a usable joint, but it takes more effort and often looks more like dross than a proper connection. There's also such a thing as defective solder. I once bought a small roll of "electronic solder" at a hardware store that was awful. The flux would sputter and spray small balls of solder everywhere. I managed to do the soldering only to find that nothing less than acetone would remove the flux residue. Alcohol wouldn't touch it. More on flux: <http://yarchive.net/metal/soldering_flux.html> Make your own flux: <http://www.instructables.com/id/Make-your-own-Eco-friendly-soldering-flux/> I've done this with violin rosin and pine tree pitch. It works. Unfortunately, it smells like a burning forest, causing everyone in the lab to panic. As for the old solder, I haven't had much trouble with flux loss with rosin core solder. I have several rolls "liberated" from a previous employer that are easily 20 years old, and are still in use. That's not the case with acid core solder (not suitable for electronics). My roll of acid core plumbing solder looks corroded. The steel reel on which it's rolled is also corroded, indicating that the acid flux is somehow leaking and attacking everything nearby. The OP's solder collection is rosin, so flux loss should not be a problem. -- Jeff Liebermann jeffl(a)cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
First
|
Prev
|
Pages: 1 2 3 4 5 Prev: Any Lighting experts on here ... ? Next: Radio Sound Schematic Help |