As far as gold is concerned, doesn't the gold alloy into the solder.  If so
the gold "underlying intermetallics" are already touched.  This might
explain the gold re-precpitating, since it won't go into an HCl solution.

>Subject: Sn-Pb etch
>Author:  [log in to unmask] at corp
>Date:    1/24/96 10:58 AM
>
>
>Can anyone recommend a method to completely remove the 63-37 solder from a
>surface, leaving the underlying intermetallics untouched?   I have tried
>hydrochloric acid; it works for solder reflowed on Cu, but in joints with
>gold it apparently re-precipitates gold artifacts.  Any help would be
>greatly appreciated.
>
>Edwin Bradley
>Motorola
>

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