Lead and lead-free solder: Question and answer, right here on sci.electronics.design

Your mind is allready made up [*must* save the world from lead] I hate single issue bigots of whatever persuasion.

What credibility do you have? You aren't willing to tell us your name (not even your first name) or anything significant about you. You aren't a doctor and provide no evidence to support your claimed technical skills. Additionally who wants to argue with a six digit number?

If we wanted a pointless argument with someone who's made is made up, we could reply to the islamic spam, at least most of them have a real naame. (not that I mind people using a handle for privacy, those of you who do, have built your own credibility on the quality of their posting history)

Put up or Shut UP - post a link to closeups of lead free boards *YOU* have built - otherwise go and try to convince NASA to go 100% lead free and dont come back till you have succeded.

I just ****ing hate Google Gropers. Anyone else here want a UDP for Goolgle?

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Ian Malcolm.   London, ENGLAND.  (NEWSGROUP REPLY PREFERRED)
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I don't think there's a single true statement in the OP's post anyway. Not a very promising beginning.

To the OP: (a) Lead-free solder stinks. It's unreliable, it forms brittle intermetallic compounds with just about any pad metallization under the sun, and under temperature cycling it produces tin whiskers that cause shorts and voids. If it weren't for European bureaucrats looking to justify their existence, no one in the world would be using lead-free for electronics. I work in an advanced electronic packaging group, and the amount of make-work that this silly decision involved is horrendous. My colleagues are very smart people, so they eventually managed to find a combination of solder alloy and complicated pad metal stacks that work almost as reliably as old fashioned lead-tin. The number of man-years and millions of dollars required for this useless accomplishment would boggle your mind, and that kind of waste makes me angry.

(b) Metallic lead has about zilch vapour pressure at soldering temperature. You're in much more danger from the flux smoke--and lead-free flux isn't nice innocuous tree sap, like lead-tin flux.

(c) Lead goes absolutely nowhere in landfills. It just sits there, and even if it were to dissolve, heavy metals move (iirc) millions of times slower than ground water. The Oklo natural reactor in Gabon went critical billions of years ago, and (apart from volatile stuff like Xe, Rn, I, and alkali metals) the entire heavy-metal fission product plume is still there to look at. It hasn't even gone a mile in that entire time, iirc, and that's in very wet conditions with a lot of flowing groundwater.

(d) Do you or anyone know of a single case of lead poisoning, of any degree of severity, traceable to electronic solder? I've never heard of one.

Cheers,

Phil Hobbs

Why do you, a hobbyist who used to work in a repair shop, presume that you can "enlighten" professionals?

I have aerospace customers who insist that we do not furnish them gear that uses lead-free solder.

John

The Romans sometimnes used lead coffins:

The lead has hung around for 1600-1800 years despite the fairly high rainfall and ground water levels experienced in England.

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Why do you think it isn\'t?

Some anecdotal evidence:

I have a friend who runs a small electronics assembly business, two people involved. Have been hand soldering PCBs using leaded solder for at least 30 years. Reasonably careful with handling, wash hands after working etc, but no special precautions. Both ested for biological lead a year or so ago, when the question was raised, found lower than background concentration for average Queenslander.

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Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
Design Engineer         J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.

Must.. resist...

Best regards, Spehro Pefhany

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I use what I have on hand which at the moment is lead basid rosin core solder.

Recently I've been going to maker type events with Providence Geeks and I was astounded how paranoid they were about lead exposure. I pointed out that if they drank the water in our fair city chances were they were getting a little Pb with every drink.

Good practice says ventilate well, and wash your hands thoroughly after handling leaded solder.

Indeed, at the maker events I've been too we all panned the lead free solder. It requires a higher temperature and doesn't bond as well one the PC boards.