OHHH! I stand corrected. If you have an acetylene torch, heat the head of the bolt, then douse it with water to rapidly shrink it and shock it loose. You can try a propane torch too but I don't think that will get hot enough. If that doesn't work, use an air hammer on the head to rattle it. If you can get on there with a wrench at the same time to put a turning force on it, that will help.
If you do snap it off, prop a nut over the remaining bolt, heat mainly the bolt but the nut will get hot too. Then fill the nut in with a wire feed welder. Cool it with water, then try turning the nut to back the remaining part of the bolt out. The reason for heating the bolt and nut first is the nut will fill with metal long before it has time to penetrate and really weld the nut solidly to the bolt. The goal, if you're steady enough, is to weld to the bolt, not the nut. The surrounding metal will try to suck the heat out of the bolt preventing good penetration. Hopefully the bolt will get hot enough to melt before the hole in the nut fills up. Stop welding momentarily if you see the sides of the nut starting to melt away. Let it cool for a few seconds, then continue filling it.
Monday, July 26th, 2010 AT 2:21 AM