Old Solder

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.

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

ust

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I have some Ersin I bought around 1990 - about 6 oz. left. Had no problem with it last week.

G=B2

I've never heard of rosin-core solder drying out. It would probably take a lot longer than just a few years to deteriorate to the point where the flux no longer "fluxed". Perfumes that still smelled have been found in pyramids.

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.

Do yourself a HUGE favor and buy some Ersin/Multicore solder, and some Kester RMA liquid flux. Between the two, there is little you can't solder properly.

Joe Inscribed thus:

Not all solder wire has flux built in ! Also you might find that "Lead Free" solder is much harder to melt, requiring a higher soldering iron temperature.

It's probably plumbing or stained glass window solder which did not have flux in it. Remember "Old solders never die".

Geoff.

On Sat, 03 Jul 2010 18:19:10 -0700, Joe ??o??:

I have a roll of solder that's maybe 25 years old. The rosin doesn't evaporate.

I bought a big roll of Ersin 63/37 solder circa 1980, and it's still fine. I assume the flux /will/ eventually "go bad", but that's likely to be long after I'm dead.

PS: The spell checkers wants to change "Ersin" to "Resin". Fascinating.

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.

I don't agree. The flux contained in the solder is adequate for fairly clean joints. If the joints are not clean and a little brush cleaning is not possible then the liquid will be a help. I use the liquid on old radio (1920- ) equipment because the copper is usually in bad shape. On most modern jobs it will not be necessary to use liquid in hand soldering.

Tom

Agreed. If the copper (or plating) is in bad shape, you need extra flux, otherwise it's just extra mess. I use powdered rosin dissolved in methylated spirits (or 95% alcahol or isopropanol) to make a saturated solution and a toothpick or small brush to apply it. Although there is no extra 'active' chemicals in it, just rosin does a good job on joints that aren't badly contaminated.

It also is good for 'holding' a freshly cleaned copper board for a few weeks while you are soldering up a project. If used sparingly on individual joints then cleanup is little worse than with fluxcore solder, though if you paint it on liberally, you will need to wash the board THOROUGHLY, ideally IPA then hot water then mist with IPA, drain and dry thoroughly.

I suspect the flux ran out while the solder was being extruded as Mr M.Terrell pointed out up thread.

t,

No, but there IS faulty and inconsistent solder product in the market... major brands (Kester, Multicore) are fine.

I'll second that. A 2 oz. bottle of liquid flux, with an artist's small brush, always sits between my soldering iron and the magnifier (so I can see bad joints, hit 'em with the flux, and reheat).

Rosin flux does develop clumps (probably just the alcohol evaporating); the water-soluble type is just as good in its own way (but you HAVE to rinse clean afterward).

...

I've got a roll or two of Multicore that's easily 3 decades old, and still works fine. Now, when doing repairs, you are often up against a filthy joint and the crufty remains of the flux last used, plus any dirt or corrosion it's attracted since it was made - and there just might be a layer of varnish or the like applied to the thing post-assembly to additionally complicate life, and none of those will help a bit.

If you can't make it clean mechanically (the preferable option, IMHO), additional flux might help.

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

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.

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

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?

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

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.

I've never had trouble "wetting" an old joint with a bit of new rosin-core solder.