Got Pb ?

by Gregory Sullivan — Monday, October 08, 2007, 09:00 AM EDT

For those of you a little sketchy on the Periodic Table, Pb is lead. Because of well-intentioned bans on lead in all products, including solder for electronic components, a new problem has appeared: tin whiskers. Tin whiskers are tiny hairlike slivers that sprout from components and solder connections made from, or coated by tin. The tiny amount of lead formerly put into solder counteracts this problem. The result of banning lead in tin solder are short-circuits that can lead to catastrophic failures of important systems that rely on electronics. And what important system doesn't rely on electronics any more?

Trouble arises when the whiskers bridge separate parts of increasingly miniaturized circuit boards. They can also flake off and interfere with sensitive optics.

Missiles have been damaged, communications satellites silenced and nuclear power plants forced to shut down. Pacemakers, consumer gadgets and even a critical part of a space shuttle have fallen victim to tin whiskers.

By some estimates, the resulting short-circuits have caused as much as $10 billion in damage since they were first noticed in the 1940s.

The amount of lead in solder needed to counteract tin whiskering is very small; but over time, it's bound to leach out of components dumped in landfills. Fear of lead poisoning has led to zero tolerance for it anywhere, including in the minute amounts needed to keep solder from degrading. They should allow lead back into solder, and demand that all electronic components be recycled. Electronic components should be recycled anyway. Between the cadmium, lithium, and other heavy metals in your typical computer, the lead is the safest thing in there. Not to mention the viruses on the hard drive.

Got Pb ?

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