
Basic Information Regarding Tin Whiskers (2008) - njoubert
http://nepp.nasa.gov/whisker/background/index.htm
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jacquesm
Tin is a fascinating material with all kinds of interesting properties. My
personal favorite: the crying of tin. Bend a piece of tin close to your ear
and you can hear the crystal lattice beg for mercy against impending metal
fatigue. When it stops crying the piece has torn.

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6502nerdface
Twelve years later, is there still no accepted explanation of how they form?

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robomartin
One of the problems is that the onset of tin whisker growth is stochastic. In
other words, we can't predict when they will start growing, it's random. Which
means they can start growing in a day, a week, a month or three years.

If I remember correctly, once they start growing the growth rate is reasonably
constant and can reach many millimeters per year.

If that doesn't sound bad at all, keep in mind that fine pitch integrated
circuit pads in modern electronics could be in the order of 0.2 mm apart.
Which means a tin whisker that grows at a rate of 10 mm/year could bridge that
gap in about one week.

I could be wrong on this, but it is my opinion we will eventually discover the
RoHS initiative backfired and we generated more consumer waste than we every
had before RoHS. I still have my 30+ year old HP-41C calculator (as well as a
small collection of other HP calculators). They all work perfectly. They don't
have lead-free solder. I doubt any RoHS era calculators will be able to
survive that long and still work. In other words, we are likely filling our
trash dumps at a faster rate than ever before due to RoHS.

RoHS:
[https://en.wikipedia.org/wiki/Restriction_of_Hazardous_Subst...](https://en.wikipedia.org/wiki/Restriction_of_Hazardous_Substances_Directive)

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throwaway_pdp09
Check out Tin Pest on youtube (can't do it at the moment). A most curious
behaviour for a metal.

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jaredandrews
Fascinating, anyone here ever experience problems due to this phenomenon?

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CamperBob2
Yes, I've seen RoHS-related whisker issues in production hardware, although
not related specifically to lead-free solder. These whiskers [1] appeared on
the body of a PCB-mounted TNC jack from Amphenol, a US-based vendor.

It's very upsetting to see this happen to your own hardware, just because some
EU bureaucrats believe that long-lasting electronic products are a bad thing
rather than a good thing. Fortunately, 6 years down the road, it appears to
have been a one-time incident.

[1] [https://imgur.com/kmb2mtZ](https://imgur.com/kmb2mtZ)

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bitwize
Lead leeching into the soil and water supply is a very, very bad thing.
Eventually, even long-lasting electronics must be disposed of, and if it
contains significant quantities of lead, it poses a risk of poisoning the
environment.

Those "EU bureaucrats" are protecting their children, and by extension yours
through a sort of regulatory herd immunity, from lead toxicity.

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CamperBob2
_Lead leeching into the soil and water supply is a very, very bad thing.
Eventually, even long-lasting electronics must be disposed of, and if it
contains significant quantities of lead, it poses a risk of poisoning the
environment._

Yeah, right. Where are the numbers? If lead "leeches" out of solder and into
the water table, it happens in microscopic quantities on geologic timescales.

Getting lead out of gasoline made sense. Solder and plating, no. At less than
0.66 grams of solder based on tin content alone [1], one iPhone built with
63/37 eutectic lead solder would contain less lead than about 20,000 car
batteries. Last I checked, we're still poisoning your children with those.

[1] [https://www.vice.com/en_us/article/433wyq/everything-
thats-i...](https://www.vice.com/en_us/article/433wyq/everything-thats-inside-
your-iphone)

~~~
CamperBob2
_one iPhone built with 63 /37 eutectic lead solder would contain less lead
than about 20,000 car batteries_

Sheesh, I'd hope so. Make that 20000 phones ~= one car battery. Must be all
that lead getting to me.

