The only reason those are exploding like that is because they are spinning them way too fast for their rating. Grinding wheels are one of those things that going cheap isn't a good idea. On pipeline we would even go so far as using a file to chip the outside of the 1/8" wheels if they started to glaze (norton brand, very high quality), i even started carrying a wheel dresser because i wanted that thing to straight up shred steel. If one would get stuck on you would lock the arbor, then bash it into a wood skid to loosen it. I've seen lots of the cut off wheels explode, if you torque on them at all in the cut they blow up. The big thing is to use faceshields, throw sparks towards you (yes that's right, so if it grabs it goes away from you), and get your head and body out of the line of fire as much as possible. With wire wheels, don't bear down too much unless you are trying to smear with it, the high rpms and the razor sharp tips are what does the cleaning, and always keep your face out of the line of fire. When they start throwing a bunch of wires, get a new one, being cheap is how you get ate up.