Reddit reviews 3M 9003NA Aluminum Oxide Sandpaper, Coarse, 9-in by 11-in
We found 3 Reddit comments about 3M 9003NA Aluminum Oxide Sandpaper, Coarse, 9-in by 11-in. Here are the top ones, ranked by their Reddit score.
The product is 4PK 60G ALO Sandpaper.Elegant Design And FinishThe Product Is Manufactured In China to The Product Is Manufactured In USA4-SheetUse to sand wood, paint, metal, plastic, drywall and fiberglass
He is referring to the fact that aluminum almost instantaneously forms aluminum oxide at its surface from an oxygen atmosphere.
Aluminum oxide, Al2O3, in its most common form also known as corundum, has a mohs hardness of 9, close to diamond, and it can readily scratch glass, which has a much, much lower hardness. Alumina is therefore a common material used in sandpaper, which you can easily buy on Amazon. If you had heard of it you would have probably asked the same question as him.
The layer of alumina that forms may not be thick enough (it's very thin) or of the right composition to form corundum, but if enough of the aluminum is rubbed off and oxidized, he is proposing that it's possible the aluminum will form into particles of corundum, which can scratch glass.
I have no data to say that this actually happens, but it's not just a crazy idea where he is questioning the wisdom of the materials science gods and their table of things that will absolutely never scratch other things.
This is about as affordable as it gets.
I used a black & decker sander with this sand paper. Then I spray painted it with flat black rustoleum. Thanks!