On Mar 1, 10:05 am, John Doe wrote:
For a small surface (2" x 2") area course roughening of aluminum.

The steel brush drill attachment I'm using requires pressing hard to
produce significant scratch marks. Is there a particular type of
steel brush that will easily roughen aluminum?

Thanks.

Don't use a steel brush. The steel bristles will leave small amounts
of iron in the aluminum and corrosion will set in shortly. Iron and
aluminum don't get along well at all.
Some form of grit (not emery; it contains iron in its makeup) is
better. Aluminum oxide is best, I'd think.

Dan