[time-nuts] RoHS Solder

Alan Melia alan.melia at btinternet.com
Fri Sep 25 00:04:58 UTC 2009

It is amazing the loops we go though. I remember being involved in whiskers
about 40 years ago. the information I got then is that tin wgiskers only
grow from pure tin, I cant now remember the level of alloying that is
necessary to suppress the growth. The problem I had tuened out to be a
"lead"tree growing electrochemically in the presence of, and inn contact
with, liquid water. However I used to have an unbelieveable photograph I too
of a silver whisker on some telemetry equipment, this was accelerated I
believe by the atmospher containing sulphur (sulfur to you) probably
outgassed from rubber based cable sheaths. Again I believe the whisker
growth is only from pure metal in this case plating. But even the thick gold
plating beloved of the military and seen on a lot of HP pcbs in the 70s
causes embrittlement of tin/lead soldered joints.

I have been using 99.25%tin/copper alloy recently and have been surprised by
the "look" of the handmade joints, quite "shiny" but I am guesing that is
not sufficient "foriegn" material to stop the whiskering, and any more would
increse the melting point. Thanks for the URL references they will make an
interesting read. (I have a large stock of tin/lead for my personal hobby
use) I wonder how much lead leeches off Cathedral roofs in areas of acid
rain like the big cities !!

Alan G3NYK
----- Original Message -----
From: <SAIDJACK at aol.com>
To: <time-nuts at febo.com>
Sent: Friday, September 25, 2009 12:38 AM
Subject: Re: [time-nuts] RoHS Solder

> That's kind of part of the scam in my opinion, we now create much more
> electronic trash in the name of removing miniscule amounts of
> unsafe lead from products..
> Forget about running your new Agilent counter for 25+ years like we used
>  be able to do...
> Another part of the scam is that only two companies (one a University if I
> remember correctly, one a Japanese company) hold the patents to the
> based solder that everyone now needs to use... And according to the USGS
> we are quickly running out of mineable Silver..
> In a message dated 9/24/2009 16:23:23 Pacific Daylight Time,
> pete at petelancashire.com writes:
> Another  article I will see if I can find it took a different
> slant. Since it can  take two to three years for a whisker to
> grow enough to cause a short. It  is a big plus for the
> consumer industry. Finally a built in failure  mechanism to
> force the consumer to have to buy again, and again, and  again.
> -pete
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