Desoldering Chips, was Re: Can someone,

Joachim Thiemann joachim.thiemann at gmail.com
Fri Apr 9 14:53:33 CDT 2010


On Fri, Apr 9, 2010 at 14:17, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
> Indeed... Over here it;s illkegal to use leaded solder on drinking water
> plumbing. For waht reason $deity only knows. The ammount of lead that
> would get into the wanter from the average soldered joint would be
> minimal. But then such regulations are rearely made by people who
> actually think what's going on.

Aaaaand just to play devil's advocate: The regulations are then
discussed by people that don't actually know what's going on either
(BTW no, I don't know either!)
- What is the safe level of lead in drinking water? For what body
mass? For what developmental stage? To what extent? You'd have to ask
pediatricians, neurologists, and biochemists - search PubMed and
you'll find they are arguing about it all the time.  Officially, for
children and infants there is _no_ safe level.  That does not mean
that every child exposed to x ppm lead in water will exhibit any
symptoms - but perhaps one will. Is that acceptable risk?
- How much lead is leeched into the water from a joint? Over what time
frame? How much variation is there, based on the skill of a plumber?
Will _all_ joints of even a good plumber be good?  What is the pipes
are disturbed in some way?  I guess one could ask chemists, maybe get
a fluid engineer as well.

There are of course places in the world where people live and raise
children with (from our POV) horrendous levels of environmental
contamination (such as the 'electronic graveyard' places in
third-world countries). But here, the cost of removing lead wherever
possible is a relatively small detriment economically; in the scheme
of things a minor inconvenience.  (I for one prefer PEX pipes over
copper anyways!)

I think that eventually everyone will be as familiar with lead-free
solder on circuit boards as "we" are with the older stuff. And wonder
what the fuss was all about.

Joe.
-- 
Joachim Thiemann :: http://www.tsp.ece.mcgill.ca/~jthiem



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