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.
The pad got to hot and melted?
Nick
Any chance the pad loaded up with galled aluminum, so that you were basically trying to polish aluminum *with* aluminum?
Abrade or machine it flat and start over...
I think that is exactly what is happening, as I have seen this exact behavior with normal abrasive discs as well. And I know they clog up readily, as the splotch of aluminum is hard to miss. I suspect that if I include a cleaning step every pass, the problem may disappear.
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
Using SiC really doesn't help at all because just as soon as the aluminum starts sticking to it, you end up with the same problem. The only thing to do is to use a lubricant to keep the aluminum from attaching itself to the abrasive and thus cause the problem.
-- Why do penguins walk so far to get to their nesting grounds?
It's commonly accepted that silicon carbide is the abrasive of choice for sanding or grinding aluminum.
Harold
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