Re: ATM Abrasives uniformity

[The Silent Observer <silent1@ix.netcom.com>]

lifedata@vol.com wrote:
> 
> How far off the average grit size would you use an abrasive?
> 
> I have some aluminum oxide rated at 46 microns.  I'm not too worried
> about small granules down to about 30, but medium power microscopic
> examination indicates there are some granules in there in excess of
> 90 microns, and I might have missed the worst.
> 
> Isn't this going too far out of range.  Won't this put scattered
> monster pits on my mirror.

Worth remembering here is that the biggest particles you're seeing are
still smaller than 220 grit, and that aluminum oxide tends to clump,
which might lead you to see a "particle" that's actually an
agglomeration of smaller particles.  As long as the larger particles are
rounded in overall profile, and don't constitute more than, say, a few
percent of the overall grit, you should be fine.

In fact, on my current mirror project, I went from 220 directly to 30
micron, and finished the 30 micron in only about a half hour; you're
likely to find you can do the same when you move from this grit to the
next finer -- say, 15 micron.

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