ATM Bklack Beauty Blasting Grit

["Stanley A. Schultz" <schultz@ucalgary.ca>]

Mike & All:

In reviewing the ATM archives I came across your posting of June 4, 2000
where you say the following about Black Beauty Blasting Grit.

> ...
> 3.    Black Beauty medium sandblasting grit
> 
>         Interesting stuff, I'll go into this more later.I changed to
> this after running out of 60 grit

> ...

> 6. In combination with the Black Beauty grit, I can work pretty fast.
> The blank is virtually flat now, so I can start with the real hogging.

>       Now a few words on this grit. I am not sure what it is exactly.
> It looks like Silicon carbide, but I'm not quite sure, because the
> grinding sludge is also very black in color. (anyone know the
> composition?)
> 
>       The grit I got was medium, I might suggest others try the fine
> grit. Medium seems like about 40 grit. If you were to use the 40 grit,
> I would advise being careful-this stuff is aggressive. Keep that
> mirror edge WELL beveled!
> 
>       This stuff is cheap: 12 dollars total for a 100 pound bag,
> purchased at a local sandblast supply business. It is also well named,
> The individual grains of grit are very pretty. At any rate, Your
> milage may vary, but my experiments ended up showing that a washer
> tool may be one of the better methods of hogging a blank out.

Without actually examining the product in hand it is difficult to make a
definitive ID of what Black Beauty really is. However, *DECADES* ago, when
my wife and I owned a pet shop in E. Lansing, Michigan, we sold a product
called "Black Beauty Blasting Grit" as a type of aquarium gravel. And,
yes, it's absolutely beautiful in an aquarium.

This product was in reality ground, sifted obsidian: volcanic glass!
In larger lumps and polished it sells in roadside tourist traps in
the American southwest as "Apache Tears" and there's some myth
associated with it.

I'll leave it to the various list members to research its physical
properties such as hardness, compared to plate glass or pyrex.

Cheers and such!

Stanley A. Schultz 
Voice: (403) 230-1911 
FAX: (403) 270-8928 
Webpage: http://www.ucalgary.ca/~schultz

"I am NOT a tourist, I've been on this planet for just HOURS!"