bluewingron. to extract a broken stud, bolt etc, by just briefly squeezing the trigger of a Mig you put a extremely high heat into the stud etc, it expands in a constricted space or area, on regaining normal temperature it has been shrunk thus affording removal. You don't need to really to deposit any extra weld metal other than will normally occur in the initial arc. As regards the ground, if you are afraid of causing unwanted arcing, just place a rod or piece of metal in the ground clamp on the broken stud or bolt and weld it there, just a little dab will do, leave it for a minute or two and extract or unscrew it. I would not attempt any repair without a Mig. I needed to change the wheels on a sliding door of a barn, we had owned it for 30 years and the door had been hung countless years before, the screws holding the wheel housing were attached to the door were the flush recessed type, just to try I used a screwdriver,that didn't work so used the Mig, I could not get a purchase for the ground so placed a small piece of scrap in the ground clamp placed it on the head of the screw, deposited a little dab from the scrap to the screw, as the screw was rusted. I use the Mig even if its just a 1/8 screw or bolt, threaded or wood screw, no need to fight anything with a Mig. Darn easier to find the Mig than a suitable sized screwdriver or wrench, (SAE or MET?) If you need to use the same bolt or screw to reattach the part you can still use it, screw it in then break off the piece of scrap, granted if it was a tempered bolt you may have altered the hardness but I doubt it, unless you've used a excessive amount of weld. Just remember, "A little Dab will do you!". Never use an 'Easy-Out' there is no such thing. To start off, the stud is already frozen in the casting or parent metal, by drilling then inserting an extracting tool you increase the pressure the broken stud already has to the metal, the problem in the first place. I submit, if you are able to remove a broken stud using any of the supposed 'Easy-Outs' chances are with care using just the flat blade of a screwdriver you could have done the same. I once worked on a farm tractor that had three broken studs on the underside, and a broken 'Easy-Out' in each sheared stud or bolt. What would have been a 15 minute job with a Mig or a stick welder, I made into a 4 hour afternoon.