M.G. Chemicals rosin activated flux formula is used in our flux-cored solder wire. Its rapid wetting and fast flowing properties results in consistent and reliable soldering every time. Cleaning becomes optional with our RA Flux core because of its non-corrosive and electrically non-conductive properties. Upper temperature limit : Do not to exceed 260 degree C (tip temperature). color and appearance: Amber Solid. Softening Point, degree C (Flux Extract): 80 degree. acid number (mgKOH/g sample): 150-160. silver chromate (qualitative halides): detection. classification per J-STD-004: ROM1. surface insulation resistance: > 1.0 x 109. shelf life: indefinite. residue removal: Not required.