[Robotgroup] lead free soldering advice

[Ed Xavier Gonzalez]

Makes me wonder why European manufacturers are trying so hard to push 
RoHS so brutally, specifically when it comes to lead.  A number of my 
US customers that sell their products worldwide have already required 
me to comply with RoHS by supplying them with compliance certificates 
for materials that I sell them, including acrylic.

By the way, from http://www.rohs.gov.uk/, [The RoHS Directive stands 
for "the restriction of the use of certain hazardous substances in 
electrical and electronic equipment".  This Directive bans the 
placing on the EU market of new electrical and electronic equipment 
containing more than agreed levels of lead, cadmium, mercury, 
hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated 
diphenyl ether (PBDE) flame retardants.]

Is this push because they're so concerned about the health affects of 
using [specifically] lead-based products, or because they're looking 
to sell more products sooner because of the eventual higher failure 
rate of electronic components due to this rather well known phenomenon?

If corrosion begins forming immediately after the lead-free solder is 
applied, then an overcoat of lacquer or some other clear surface 
treatment that prevents oxygen from passing through would need to be 
applied subsequent to soldering to keep this phenomenon 
from  starting the contamination process, or at the very least, 
mitigating it somewhat.  It would need to be thickest where the tips 
are the sharpest, making the post-soldering handling of the board ugly.

In the event a small area ANYWHERE on the board pokes through the 
coating, this protective surface would be compromised and the whole 
board potentially subject to oxidation.  Consider how sharp all those 
wire tips and leads are all over the board surface, just ONE needed 
to make the entire unit suspect.  Those military guys are kind of smart, huh?

Les, just because someone asks an uncomfortable question, it doesn't 
make them a cynic, just less gullible.

Poo-On, Les!  Poo-On!

---------------------------------

At 01:42 AM 5/24/07, you wrote:
>The following message is brought to you by Mr. Poo-Poo:
>
>I was talking to an engineer friend who designs circuit boards for a 
>living the other day. He gave me some advice about lead free solder 
>-  don't use it. Apparently the lead keeps crystalline "whisker" 
>formations in check. He said the lead free solder starts to corrode 
>immediately after use, and in the process forms microscopic 
>conductive whiskers that grow over time, eventually shorting with 
>other traces. It is for this reason that the US military forbids the 
>use of lead free solder. Apparently they don't want equipment 
>failing in the field. Neither do I. Although in truth I rarely use 
>my equipment these days anyway, much less out in a field.
>
>Bye now,
>Mr. Poo-Poo
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<The right to Free Speech does not diminish the value of remaining silent>

Ed Xavier Gonzalez
Oak Hill Laser
ohlaser at swbell.net
(512) 288-5243