Mr. Boulais,
You neglect to say what flux chemistry you are using, rosins, water solubles,
low solids, etc.  It may be possible to use a titration method to determine
the amount of flux present.  We attempted such a titration method in the IPC
Phase 3 low solids flux project to determine the amount of low solids flux
applied to the test boards.  We had limited success, but the low solids flux
was 95% isopropanol and the evaporation rate was high.  Such a method might
work on the more acidic RMAs and OA fluxes.  Les Hymes, The Complete
Connection, may be able to provide you more information.
Doug Pauls
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