Bob, The flux we use for SnPb and SAC is the same. However, the flux does not work well with SnBi. The solder looks good, but does not form a good bond to the Nickel (our boards have NiAu finish). We use a different flux that is, according to the supplier, formulated with a lower activation temperature. It does work better. Guy -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner Sent: Thursday, September 27, 2012 1:13 PM To: [log in to unmask] Subject: [TN] Flux Activation Temps Hi, I was looking though some paste datasheets which show a paste "Family" available in different alloys. My Question: Is a single flux formulation being used with these different alloys? It seems so. But the various melting point have a serious range. And I remember from my college chemistry days that reaction rates double for every 10 C rise in temp. (Is that still correct?) So I would expect fluxes to be relatively "Inactive" al low leaded temps but then going super-fast at higher lead free temps. Can anyone clarify? Is it a real issue or hogwash-worthy. Thanks, Bob K. ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________