At the risk of jumping into this thread, and hijacking, I will add my two pennies:
I use wire brushes on my Makitas. About 14,000 RPM IIRC. If not, they spin pretty fast.
I bought the types of brushes that have straight wires, and found that they fly off LOTS. Unless you are using them for very very light touch finishing.
What I found I preferred were the CUP KNOT types of wire brushes. They have several strands, and each bunch bound together in a spiral. They fly off MUCH LESS.
That said, ON ANY TYPE OF ELECTRIC WIRE BRUSH, be it chucked up to a low RPM drill or to a high RPM hand grinder, WEAR FULL FACE PROTECTION. I pull strands regularly from my Wrangler khaki shirt fronts and sleeves. I have even pulled them from my skin in various places. I like to wear clear safety glasses AND a face shield when using these little tigers.
I have gotten metal fragments in my eyes two times that had to be removed by a doctor. BOTH times, I had safety glasses on.
Point is, cup knot brushes let loose fewer strands than straight wire cup shaped brushes. Even spiraled stringer brushes (flat type rather than cup style) throw off fewer strands than regular straight strand stringer brushes.
Burn up ten to twenty of them and compare the results. Hoping you have worn proper eye protection in the meantime, and can report back your findings, that is.
There is no meaner piece of machinery in my shed than my little grinders, whether they have a wheel on them or a brush.
THEY'RE NASTY LITTLE BASTARDS. And any time you tangle with them, you lose.