You can still weld a nut on it, even broke off flush. They offer special weld rods for it, but it's more the technique that counts, not the rod. Just use any good rod ( arc weld ) and build up on the bolt, a little at a time. Of course, you will probably get the EZ out , not the bolt, but just as good. After you have a nice dimple built up on the bolt, then set the nut over the dimple and weld the nut to the dimple. First, I'd suggest to try righty-tighty to see if the ez out will pull out. If not, then lefty loosie and see if the fastener might decide to let loose ( lots of heat from the weld )