95 RX Flux is low-VOC technology developed for vintage soldering machines that use foam fluxers. Can foam up to 0.5" high; reportedly will not creep out of slots and PTH. Water content provides strong foaming bubbles that carry kinetic energy; assists in cleaning surfaces and gets flux in holes that need to accept solder. Prevents solder balling, with a minimum amount of residue.
Cobar Solder Products, www.cobar.com
Balver Zinn Group, www.balverzinn.com