Another thought - try using the silicon carbide grades of Scotchbrite.
They cost a bit more but you will be hitting the surface with a grit
that's harder than the aluminum oxide coat already there.

Eric R Snow wrote:
On Tue, 27 Sep 2005 13:51:10 +0200, Shon Shampain
wrote:


I was working a thin (3mm) piece of aluminum plate with a rotating disc
on a hand drill. On the disc was a cutout of scotchbrite. *All of a
sudden* the aluminum went from having beautifully fine arcing scratch
marks to this hard marble orange peely crap. I assume that *something I
did was wrong* and that the work is now "work-hardened"?

If so, or not, how would I prevent such a thing? Is it a matter of use,
speed, heat, or what? And how can I remove it from the piece I have.

As always TIA.

You are trying to abrade aluminum oxide. It's hard. Clean the
scotcbrite or use new. Use some kind of cutting lubricant. Kerosene,
WD-40, light cutting oil, wax etc.
ERS