"Houston, we have a problem" Sorry, I just had to say that.

Listen, using a wire brush on a grinder is about the worse thing you could use. I have tried many different ways over the years and wire brush seems to "polish" the paint more than remove it. It creates LOTS of heat
A much better way it with 3M "ROLOC" or "Clean and strip" discs. After you have used them, you will throw the wire brushes in the garbage.