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From: Joe on 3 Jul 2010 21:19
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
From: John Fields on 3 Jul 2010 21:54
On Sat, 03 Jul 2010 18:19:10 -0700, none(a)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?

---
Dunno.

I've got rolls of Kester and Ersin that I bought years and years ago
where I can still smell the fresh Frankincense and Myrrh and are hard
to make a cold joint with, and I've got some Alpha and some other
brand that I wouldn't use on plumbing without external flux.

Do you know whose solder you're using?

From: Grant on 3 Jul 2010 23:41
On Sat, 03 Jul 2010 18:19:10 -0700, none(a)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?

Got to try it, I think. I don't like using solder so old it's turned
black.
>
>What happened to the rosin core of that solder? It doesn't look like the
>end was left open.

I've seen really old solder where the rosin leaked out the end or oozed
out along the solder wire.
>
>Is there a definite life for unused solder?

Not that I know of, but oldest solder I have here is only ten or twelve
years, it used to be in the boot of a previous car, it's really dirty
so I left it in a box somewhere.

Grant.
From: Michael Robinson on 3 Jul 2010 23:52

"Joe" <none(a)given.now> wrote in message
news:none-0307101819110001(a)dialup-4.231.175.251.dial1.losangeles1.level3.net...
>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

Maybe the rosin dried out.
Also you need a clean surface for the solder to flow onto. Even with good
solder, you can have problems if the copper is oxidized and dirty. It's
very hard to solder to tarnished copper parts.
If cleaning is impractical, it helps to dab some flux on it before
attempting to solder.
How heavy was the part or wire you were soldering? The soldering tip must
have more thermal mass than the part you're soldering.


From: Joe on 4 Jul 2010 01:05
In article <lppv261quq572fj413r2uaupde4a5pvtua(a)4ax.com>, John Fields
<jfields(a)austininstruments.com> wrote:

> On Sat, 03 Jul 2010 18:19:10 -0700, none(a)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?
>
> ---
> Dunno.
>
> I've got rolls of Kester and Ersin that I bought years and years ago
> where I can still smell the fresh Frankincense and Myrrh and are hard
> to make a cold joint with, and I've got some Alpha and some other
> brand that I wouldn't use on plumbing without external flux.
>
> Do you know whose solder you're using?

John,

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.

--- Joe
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