Re: ATM Bklack Beauty Blasting Grit

["Peter John Smith" <pjifl@bigpond.com.au>]

Stanley Schultz wrote :-


> > 3. Black Beauty medium sandblasting grit

> > 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.

> 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.

There was a product sold in Australia that sounds just like this.

It was I believe a byproduct of copper smelting so would have been copper
slag crushed and graded.  It was very heavy and looked quite a lot like
Silicon Carbide (carborundum).  I have never used it like carborundum in
grinding glass but it sand blasted steel well.  Never tried it blasting on
glass.

I have not confirmed that it was actually copper slag but it sounded
reasonable.  It certainly could never have been silicon carbide for the
price.

Peter Smith.