it is in the formulation. your vendor should tell you. e.g. "6 Feb 2015 ... Kester 186-18, under MIL-F-14256, was QPL approved as Type RMA. ... Type RMA flux. This flux possess high thermal stability for soldering multi-layer assemblies which require a high preheat temperature. Exposure to high preheat temperatures ... The flux residue is also moisture and fungus resistant." On Apr 9, 2018, at 6:03 PM, David Hillman wrote: > Hi team! Looking for TechNet's sage wisdom. Some folks are familiar > with > this but many electronic modules have a "shall not be a fungus > nutrient > material" in terms of the components materials, laminate > materials, etc. I > was asked the question if "properly reflowed flux materials are > classified > as non-fungus nutrient supporting". Does anyone have an knowledge/ > data on > properly reflowed flux residue being "non fungus nutrient supporting"? > > TIA > > Dave Hillman > Rockwell Collins > [log in to unmask]