Bar's Leaks leak stopper.That stuff works to a point,but if the hole is big enough,you might have to get it soldered at a radiator shop.Most shops will just get a whole new radiator,cause they don't want to mes with the new ones,the ones with the plastic tanks.
Way the best is to buy a new radiator and install it. Next, go to a body supply shop and ask for Vette adhesive. It will work way better than jb weld or anything else I have ever used. Maybe it is what one of your answers called glass stuff, I don't know.
Try some Bars leak. J.B. weld will not hold pressure as the Radiator can be copper, aluminum or plastic. If it's copper it can be soldered if you know hw to but must drain the Radiator in fact all the fixes you will have to have the water out of it first. Then if you use Bars Radiator leak drain all the antifreeze out and put in cold water then add the Bars Leak. run it for an hour and watch to see if it seals, if it does drain the water add anti freeze. then get it replaced at a shop. I would drive it to a local radiator shop and get an estimate it's worth not losing your engine over.
