PSN-L Email List Message

Subject: Re: soldering pad tips...
From: Karl Cunningham karlc@..........
Date: Sat, 09 Feb 2002 08:48:58 -0800


Charles --

Sounds plausible, but I'm not so sure.  Some rectifiers used to have silver
leads for improved heat sinking, or so the manufacturers said.  The leads
did have the look of silver and were VERY soft and often tarnished, but
they didn't dissolve into the solder (at least not enough that you'd
notice).  I do know that dissolving of copper into solder is a problem, but
only with very fine wire (~#44 & smaller).

Anyone care to try the old dime test?1

Karl Cunningham


--On Friday, February 08, 2002 09:33 -0800 "Charles R. Patton"
 wrote:

> Bob Shannon wrote:
> "So I heated the solder to see what had happened....Guess what? NO
> DIME."
> 
> My guess is that the dime went into solution.  Dimes were silver which
> is very soluble in lead/tin (solder.)  This is why there are solder
> alloys with  1 to 2 % silver available for electronics, primarily SMT
> components which used to commonly use silver terminations, in order to
> avoid dissolving the termination when the component was soldered on.
> 
> Charles R. Patton

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