cujo8,
My 5 cents...use a ridgid grinding wheel, not a
disc. If the grit of the wheel isn't coarse enough, you usually end up polishing/grinding and this is what takes the time. There is a wheel on the market called AVOS, which is an acronym for "Allows View of Surface". You can see the weld area as you grind it down. Stay with a coarse grit, 36 or 46.
If you grind the area down flush, then your weld needs to be 100% or you have NO weld left. The coarse wheels combined with the proper weld wire (MIG) make for a easy grind. The area being repaired will have primers and fillers applied to it, so a little rough might be better than smooth as glass. The coarse grits will remove metal faster and with less heat than a finer, fiber type disc.
Stuart.
