Old Solder

[Meat Plow]

On Sun, 04 Jul 2010 07:28:40 -0700, Smitty Two ǝʇoɹʍ:

In article
none-0307101819110001@dialup-4.231.175.251.dial1.losangeles1.level3.net
,
none@given.now (Joe) wrote:

A couple of days ago I did a small repair to an electronic timer. It
just need a bit of solder to reconnect a wire.

I had a devil of a time with that small repair, the solder just didn't
want to flow over the wire and onto the pad on the PCB.

A little while later, it occurred to me that maybe the problem was that
I had used some old solder - about a foot or so are remaining on
probably a 5 or 10 foot spool.

The big Aha! came when I realized that all during that soldering
attempt, there was absolutely no odor of rosin flux.

Questions:

Are there any obvious ways to tell if old solder has lost its flux,
other than trying it out on say, soldering some scrap wire?

What happened to the rosin core of that solder? It doesn't look like
the end was left open.

Is there a definite life for unused solder?

--- Joe

I'm the militant s.e.r. liquid flux advocate. If you're going to solder
at all, especially to make repairs, you *need* liquid flux, period. One
of these days I'll make a video for youtube demonstrating how flux
facilitates soldering. I don't care if you think you've been soldering
fine without it for 50 years, if you don't use it, you have no idea what
you're missing.

Never used anything but rosin core flux except to solder copper pipe.
Maybe you could 'explain' what it is I might have been missing over the
last 30 years?

 

[Meat Plow]

On Sun, 04 Jul 2010 14:19:12 -0700, David Nebenzahl ǝʇoɹʍ:

On 7/4/2010 3:36 AM Michael A. Terrell spake thus:

Joe wrote:

I have two spools of Radio Shack 63/37 rosin-core solder. One of the
spools is almost empty (the one that I had the problem trying to
solder with), the other looks at least half full.

Both spools have the Radio Shack stock number 64-015, but they have
different artwork on their labels, and the old plastic spool is black,
the newer plastic spool is white.

The older spool quite possibly dates back to around 1980.

Radio Shack solder was low quailty, years ago. I won't buy it. It
used a low grade flux, and the core was inconsistant. if you didn't see
smoke when you touched it to the work, then it had no flux. The rosin
is dry, anyway. It was the old acid core solder that was liquid.

Not *necessarily* true that RS solder was low quality: I have a roll
I've probably had for 20 years, RS # 64-009A, 60/40, .032 dia. (I call
it "angel-hair pasta") standard rosin-core. Works great.

Dunno about their other solders, nor about what they currently sell,
which could well be crap.

Sounds like what the O.P. was using wasn't rosin-core, anyhow. The flux
doesn't disappear since it's solid.

I've had a big roll of RS fine solder for ever. Other than the fact that
it's too fine for regular soldering PC stuff etc...it's great quality.

 

[Michael A. Terrell]

David Nebenzahl wrote:

On 7/4/2010 3:36 AM Michael A. Terrell spake thus:

Joe wrote:

I have two spools of Radio Shack 63/37 rosin-core solder. One of the
spools is almost empty (the one that I had the problem trying to solder
with), the other looks at least half full.

Both spools have the Radio Shack stock number 64-015, but they have
different artwork on their labels, and the old plastic spool is black, the
newer plastic spool is white.

The older spool quite possibly dates back to around 1980.

Radio Shack solder was low quality, years ago. I won't buy it. It
used a low grade flux, and the core was inconsistant. if you didn't see
smoke when you touched it to the work, then it had no flux. The rosin
is dry, anyway. It was the old acid core solder that was liquid.

Not *necessarily* true that RS solder was low quality: I have a roll
I've probably had for 20 years, RS # 64-009A, 60/40, .032 dia. (I call
it "angel-hair pasta") standard rosin-core. Works great.

The RS solder I tried would spit blobs of solder, due to an uneven
flux core. I checked several rolls of it of a few years but cutting it
open. There were places the wall was very thin, and others with no
flux. I finally wadded it up and tossed it into a solder pot we used to
tin wire.

Dunno about their other solders, nor about what they currently sell,
which could well be crap.

Sounds like what the O.P. was using wasn't rosin-core, anyhow. The flux
doesn't disappear since it's solid.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

 

[Smitty Two]

In article <pan.2010.07.05.13.58.47@gmail.com>,
Meat Plow <mhywatt@yahoo.com> wrote:

On Sun, 04 Jul 2010 07:28:40 -0700, Smitty Two ??o??:


--- Joe

I'm the militant s.e.r. liquid flux advocate. If you're going to solder
at all, especially to make repairs, you *need* liquid flux, period. One
of these days I'll make a video for youtube demonstrating how flux
facilitates soldering. I don't care if you think you've been soldering
fine without it for 50 years, if you don't use it, you have no idea what
you're missing.

Never used anything but rosin core flux except to solder copper pipe.
Maybe you could 'explain' what it is I might have been missing over the
last 30 years?

What you may have been missing is the speed, ease, and quality of
soldering with liquid flux vs. relying solely on the resin core. Here's
just a couple of examples off the top of my head, without benefit of a
full pot of coffee yet:

1. Try assembling a through-hole board with several hundred components
by hand. Hell, try installing one component, say a 14-pin DIP. Then
inspect the top side to see how much solder actually flowed all the way
through to the top side. Without flux, many or most of the joints would
be rejected. Without flux, you will spend at least five times as long
doing the assembly.

2. Try installing a QFP100 without flux. Time your effort. Inspect the
results under a microscope. Can you spell "slow and ugly?" Now try flux.
Once the chip is positioned, you can easily make all 25 solder
connections along each side with a single drop of solder on the tip of
the iron. Just spread a drop of flux down the row, and skate the iron
down it. Takes about 1-2 seconds to make 25 perfect solder connections,
with no bridging thanks to the flux. Same technique used on any surface
mount package of more than a few pins.

3. Try tinning stranded wires without a little additional flux. Chances
are you'll take five times as long, and the solder won't penetrate to
the center very well.

4. For cold or cracked solder joints on repairs, there's already plenty
of solder on the joint. A single tiny drop of liquid flux will let you
reflow what's there with far more elegance than gobbing on a big
additional wad of solder just to release a speck of flux from it.

5. Maybe this one should have been first: Ever needed three hands to
solder something? One to hold one of the parts, one for the soldering
iron, one for the solder? Say a butt joint on a couple of wires, or
adding a pigtail to something, or hanging a capacitor off the back side
of a board as a temporary fix? Try this:

Put a bit of solder on each part. Hold parts next to each other and
put a drop of flux on them both. Now reflow the solder with the iron.
You absolutely, positively cannot do this well without liquid flux, yet
the need to do it comes up almost daily for anyone that does any
reasonable amount of soldering.

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.

 

[Jeffrey D Angus]

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

 

[Jeff Liebermann]

On Sun, 11 Jul 2010 10:46:33 -0700, Smitty Two
<prestwhich@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@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558