"Arfa Daily" wrote in message
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"ian field" wrote in message
news

"Arfa Daily" wrote in message
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"mc" wrote in message
.. .
Given that it's desirable to do repairs with the same type of solder as
was used originally, in order to avoid alloy mixing or partial melting
problems...

(1) How do I recognize lead-free solder when I see it?

(2) What temperature should I set my iron to, when working with SnSb or
SnAg solder?

Thanks!


It has been recommended by the creators of the half-arsed RoHS
directive, that manufacturers mark their boards with the alloy that has
been used. To date, I think I have probably seen about 2 or 3. In
general, boards made with lead-free, look as though every joint is bad
( and often, this is pretty much the case !! ). Instead of the joints
having a shiny appearance, and being domed or meniscus-shaped, they are
dull and grey, decidedly 'crystalline' looking, and tend to be
volcano-shaped, with straight sides.

snip

Any chance the half-arsed RoHS directive was thought up by the stuck up
gits who pepper the countryside with 12bore lead shot?

Most shot used in clay shooting is no longer lead, I seem to recall.
Anyway, the point is that if it is, it is not recycled, so remains lying
where it is. Solder accounts for less than 1% of the world's mined lead,
over 80% going to car battery manufacture. The car battery industry have
managed to organise virtually 100% safe recycling, so are allowed to carry
on using lead on this basis, and the contention that there is no suitable
alternative. With the coming of the WEEE directive shortly, end of life
electronic equipment will have to be safely recycled in much the same way,
so where's the difference ? If the car battery people can do it, I'm sure
that the electronic people can also do it with less than 1/80th the
volume.

The point about the RoHS directive as it stands with regard to leaded
solder, is that it is forcing a changeover from a mature, tried and tested
technology, which had reached the point of almost perfect reliability, to
a less than satisfactory alternative, with at best, woolly reasoning to
try to justify it. This is well understood by such people as the US
military, who refuse to use the stuff, the avionics industry, who have
obtained exemptions, and the medical instrument industry, likewise. Any
ecological advantage from the poisoning angle, will probably be outweighed
in the long run by the additional energy budget worldwide to run all those
solder production lines and hand soldering irons 50 degrees hotter, and
all the extra recycling brought about by electronic equipment being junked
earlier due to owners getting fed up with all the intermittent problems
from bad joints ...

Just keep your fingers crossed that avionics are not finally forced down
that route, coz that'll be the day that I stop flying.

Arfa


Some good points there, I didn't know lead was no longer used for 12bore
shot - any idea what they use instead?

Regardless of the WEEE directive, lead was originally mined out of the
ground and one way or another it will eventually end up back there, also I
had always held the opinion that the common solder alloys were substantially
less toxic than lead on its own, if this is true then the manufacture of
lead/tin solder actually reduces the availability of lead wherever it ends
up at end of life.

One thing I have been trying to find out if anyone knows, is how much lead
the petroleum industry procured annually for TEL additives before leaded
petrol was discontinued, the figures I read somewhere (can't remember where,
or how much!) were huge - thousands of tons of lead converted into exhaust
particulates to be inhaled, washed onto agricultural land and into the water
table, I suspect that lead in solder is insignificant compared to previous
usage of TEL!