There are also some welding procedures that specify that if you grind or even wire brush your weld, you automatically fail. No excuses, no exceptions. Rutterbush is completely correct in correcting me about the direction of grinding and I thank him for doing so. IDK what in the world I was thinking, but he is correct. Grind in the direction of the highest possible stress. In some cases, if you just need something to hold, I've known people to just take a 6010 rod, crank up the amps and burn that baby in. And then take a 7018 and go over it in several passes and just grind it off to make it look good.
All-in-all, Rutterbush is most certainly correct. It all depends on what it is being used for.