Re: [ATM] industrial polishing pads?

[Mike Lockwood <melockwo@uiuc.edu>]

Hi,

David Harbour wrote:
> Okay, if they are about one micron in diameter, why not try 2
> micron aluminum oxide directly on the pitch? I have read where one
> can pre-polish on pitch with small abrasive, very fast. I have
> never tried it; I was tempted, but somehow never got around it. Why
> don't we find a less problematical way to cut down on fine
> polishing time than pads? Anyone game to try this proposal?

Cerium oxide for general polishing is often 1u-2u in size, but 
grinding to 1u with aluminum oxide is very beneficial and will cut 
down on polish time.

If you are grinding glass on glass, you can go from 5u to 3u to 1u 
with no problems if you filter your water.  Be gentle - with the 
smaller grits (5u and under), for the first few minutes it will feel 
like nothing is happening and the mirror/tool is just gliding on the 
surface tension of the water layer.  Do NOT apply pressure to try to 
fix this - just keep working.  After a little swarf builds up, the 
surface tension is broken (soap might help too) and the disks manage 
to get a bit closer and grinding really begins.

An extra 1/2 hr of 3u and 1/2 hr of 1u will save you hours of 
polishing, and the physical effort is almost nothing.  After a nice 1u 
grind the mirror becomes transparent.  There's just something about a 
1u-grind that is quite beautiful.

	Mike Lockwood

PS - I am also getting two error messages from someone's server every 
time I post to the ATM list.  It's annoying.

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