Just discovered a feature of lead free solder.
Experienced crystallization fractures in several old joints causing connection problems.
Must be part of planned obsolescence by big brother, buy a new one from us in a few years. 
Have others experienced this observation.
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Which blend?
96.5% Tin / Silver 3% / 0.5% Copper solder composition.
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So SAC305. That is what I use. This is the exact product...
I have not had any failures. I don't see anything suspicious on the boards I can easily access.
However, all my stuff is low voltage / low current / battery powered. Maybe that makes a difference?
However, all my stuff spends its time inside. Maybe temperature variations make a difference?
However, all my stuff is small. Maybe PCB flexing makes a difference?
There is some mumbo-jumbo on the MG Chemicals website about "purity specifications". Does your solder "exceed J-STD-006"? 
http://www.circuittest.com/srw-lfs-080-100-lead-free-silver-solder-0-8mm-100g-roll.html
To be fair, the circuit was sitting outside at about -27'C for the last week.
But still, never had this happen with leaded solder.
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I found this...
In terms of thermal fatigue...
• Pb-free solder does much better than eutectic Sn-37Pb solder (the authors were surprised; I suspect you will be as well)
• More Ag is better
• SAC305 is a good choice
• Bigger temperature extremes dramatically increase the likelihood of failure
• You just had a stroke of bad luck
(Assuming I understand and they know what they are doing.)
they know what they are doing.)
Cause they know, they know that what ever they do is not going to be better than lead. But having turned the world of electronics round with stupid and totally unnecessary legislation they have to pretend it is alright. But ask your self this, why is military equipment exempt?
I don't know how many times I've read the title to this thread today, but my mind insists on seeing it as "Crap free lead solder"
Hi, I have only one thing to say...
Kester 44
What is the rated temperature range for the alloy you used?(*) -27C is not commonly encountered in electronics
and may require more careful choice of solder alloy. And what is a "recrystallization fracture" - doesn't sound
like a low-temperature mechanism (unless related to tin-pest).
(*) This doesn't seem to be an easily available specification, from a quick google around. People seem to thermally cycle 0--100C, or similar.
Hi all..
this whole RoHS business ( restriction of hazardous substances ) is madness in repect of leaded solder.
Many lead compounds are seriously poisonous, but not metallic lead, When it hits your tum it faces 0.1 Molar hydrochloric
acid , which immediately coats it with lead chloride - a very insoluble salt. It can't go any further.
In any case , who's going to chew circuit boards?.........
There are a few exemptions - Military, medicaL, and 'infrastructure critical' eg mobile phone base stations and microwave datalinks. Why? 'cos everybody knows leaded solder is better. It's less brittle than the replacements and requires lower working temperatures which gives every other component an easier time in manufacture.
Just for fun, consider your motor car . It has loads of electronic gadgets - from the engine control unit to the widget
which adjusts your seat and of course the alternator voltage control box. All of these have soldered components which you can bet are rigorously checked to be lead free just in case you might be tempted to eat them.
So you're safe.
Or are you?
In the engine compartment there's a lead-acid battery containing 20 pounds of lead metal and oxides - and the oxides ares definitely nasty if you ingest them. Fancy chewing that?
madness.
Allan.
Grumpy_Mike:
But ask your self this, why is military equipment exempt?
Because, we had a school that taught us to not lick circuit boards.
Larry, what flux did you use? Are you sure the iron was hot enough? I don't personally care for the Pb-free stuff, and won't be using it until the last of the "good stuff" is banned from consumer use. It's for our own good, as they will say. It's the same people who said CFL bulbs were for our own good too.
I use a general purpose liquid flux for electronics soldering, don't have the part number any more.
I use 400-450'C when soldering lead free stuff.
It's just a pain, I will not be using this solder any more.
CFLs are crap too.
As I mentioned once before, all the sloughs in Canada are filled with lead from hunting.
Europe is saturated from the wars.
I am tired of bleeding hearts.
Thought I would try the stuff, not any more.
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Yeah, one should not ask if a "new and improved" product is crap, but rather if it is cheap crap or expensive crap. Sales and marketing guru's are a clever bunch, particularly when they have the blessing of the government.
It reminds me of a story that was in the paper of how the state bought a whole bunch of solar panels for the state patrol cars, so they didn't have to keep the cars running while they were in the median trying to catch speeders. It only cost like $700 per car, and was supposed to save loads of money in fuel. At the end, they stated it was a 5W panel.
5W ???
Sounds like that grovernment is as smart as ours.
LarryD:
5W ???
Sounds like that grovernment is as smart as ours.
Nowhere as smart as the people who believed it. The media even threw in their auto/electrical knowledge to imply they could use the heater and a/c. The government said it, the media printed it, so it MUST be true. People also wonder why the world is the way it is.
As for that government, it seems to be just south of your border.
Government,!
When Boris Johnston was thinking of running in the UK i could not stop thinking of the Simpsons episode with President Trump.
Gulp.
Was it Tin pest, if I recall cold can start it and then it needs some warmth to speed along.
http://www.indium.com/images/blogs/drlasky/files/TinPestPaper0723Final.pdf
LarryD:
Just discovered a feature of lead free solder.
Experienced crystallization fractures in several old joints causing connection problems.
Must be part of planned obsolescence by big brother, buy a new one from us in a few years.Have others experienced this observation.A hobbiest has no obligation to use lead free solder.
Hobbyists have no obligation to use lead free solder.
Why anyone would subject themselves or their PC board to such abuse is beyond me........
Grumpy_Mike:
Cause they know, they know that what ever they do is not going to be better than lead. But having turned the world of electronics round with stupid and totally unnecessary legislation they have to pretend it is alright. But ask your self this, why is military equipment exempt?
Because for military purposes, reliability is much more important than BS euro-politics.