Hi Guys, the ISO is short for ISO FULCRUM, an old term from the 60's meaning a hinge style chassis.
Check out this link, it shows and explains it better than I ever could.
http://slotblog.net/topic/3670-the-point/I too have trouble getting that flux, the local suppliers don't stock it any more.
Maybe you could find some BAKERS soldering paste, that stuff also does the same job as Fluxite.