[ATM] Will Alum Oxide fine grind quartz blank?

[Richard Schwartz]

Has anyone tried to make abrasive by oxidizing aluminum foil or cans  
in air at high temperature?  I got a fine powder when i tried to melt  
cans in my kiln.

Sent from Richard's iPhone

On Oct 8, 2009, at 16:43, Anthony Stillman <atmer at flash.net> wrote:

>> Will Alum Oxide fine grind quartz blank?
>
> My experience with quartz, and by quartz I mean fused silica, is  
> that grits behave on it compared to pyrex (borosilicate) as if they  
> are one and half to two grits finer.  60 grit behaves like 100, 80  
> like 220, 600 like 9 micron and so on. Also the grit breaks down  
> much more quickly.  What would be a one minute wet on pyrex might be  
> only 10 seconds on quartz. Since mostly alpha corundum is used for  
> fine grinding it can seem like it isn't doing anything.   
> Incidentally di-aluminum tri-oxide is harder than silicon carbide.   
> It's a 9 as opposed to 8 to 8.5 on the mohs hardness scale.  Fused  
> silica is nearly a 7.  The mohs hardness scale is pretty linear  
> except for diamond (10) which is 50 to 100 times harder than  
> saphire(9) depending on the diamond's origin.
>
> I've tried mirror grinding with fine diamond powder, scratch city.
>
> Anthony
>
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