I recently became aware of the phenomenon – not that I think it has posed a problem with any electronics I have been in contact with: I only solder the odd cable and some reasonably uncomplicated DIY circuit kits – but I learned that tin whiskers have always been there, and that now with lead-free solders they are going to multiply, posing a real threat to our beloved electronics – if not life as we know it.

Here’s a place to see some: http://nepp.nasa.gov/whisker/

I just wondered if anybody had given the problem, and how to avoid it, any thoughts.
- And if there really is a problem, or we should safely leave the worrying to people like NASA who, with a habit of placing their circuits where they cannot later easily get at them, have a bit more at stake.

Regards
Coincidal.

Hey Coincical, from everything I’ve read, the official word on tin whiskers is that nobody really knows why they occur or how to prevent them (see link below for latest mitigation theories). I could be wrong on this, but I believe tin whiskers are not a problem with standard tin-lead solder, but are more likely with all-tin platings, in particular, bright-tin platings. And yes, the switch to lead-free has brought this issue to the forefront recently.

For the typical hobbyist or prototype maker, I don’t think they’re of much short term concern. I think they form after years usually, not months, but there are probably exceptions. Corrosion from not cleaning water-soluble flux is probably more likely to cause problems.

One of the best things I read on tin whiskers doesn’t appear to be downloadable anymore: http://www.globalsmt.net/content/view/1157/151/ (the pdf). I emailed to see if they still have the article and will post it here if they find it.
update: The editor of Global SMT & Packaging graciously sent a copy of the pdf which I’m linking here: Tin Whiskers.pdf . It is written by Speedline Technologies, Inc.

The latest industry consensus that I could find. This powerpoint on tin whiskers has some great pictures and also discusses mitigation strategies.