Tin whiskers, crystals or long strands of tin that literally grow out of a
solder joint, have always been a low level problem with tin lead alloy
solder. But the environment had to be just right for them to grow and they
usually only caused a problem on connectors with closely spaced solder
joints.

But it's becoming a real problem with lead free solder and the "experts" in
solder chemistry don't know why yet. Part of the problem with lead free is
tin whiskers seem to grow any time & anywhere, even in a clean & low
humidity environment. The real concern is with ultra-reliable electronics
used in the aircraft industry and because of this lead free solder is not
allowed in some assemblies. It seems like maybe it's not a wise idea with
some car assemblies either.

Everyone is on the ROHS (lead free) bandwagon and I'm sure that's why
Toyota's supplier used lead free in their sensor assembly, but expect some
industry push back if this one isn't solved soon.

Thanks, Tom Hargrave
www.stir-plate.com
www.towercooler.com
www.kegkits.com

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
David Beierl
Sent: Friday, January 13, 2012 8:07 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: OT - Toyota unintended acceleration

At 06:55 PM 1/13/2012, Edward Maglott wrote:
>interesting.  I had no idea that there was an International Tin Whisker
>Symposium.

I suspect it's going to get to be an even bigger deal as the various devices
made under ROHS rules (no lead solder) age.

Yrs,
d
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