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.


Nyet!

What you want is a "scotchbrite" type wheel!
Other companies make similar stuff... it is an abrasive imbedded
synthetic wheel.
They also make it in pads that are similar to what you buy in the
store to clean pots (they're "plastic"??) but much more abrasive
and intended for metal work.
You want one that is fairly abrasive to get good "brush marks"

The alternative is an aluminum oxide paper, about 120 grit and some
oil, and smooth hand action - that's ok for doing just a little bit.
clean the oil off when ur done. If ur not finishing it with a clear
coat or anodize, you might want to use a heavier grit and then etch
it slightly with NaOH (lye) or "oven cleaner" which will impart a
slightly duller surface, but more immune to finger prints making
permanent marks on it...

You do NOT want a hand held belt sander (they gouge the work).

The way it is done in production is either the "scotchbrite" stuff
or a "Stroke Sander" rig... that one uses a belt...

Look at McMaster Carr online catalog, they show this stuff...

_-_-bear