Re: [ATM] ATM: "Fortune favors the bold"

["Bob May" <rmay@nethere.com>]

I don't like the idea of putting an abrasive of AlO2 on pitch as
it is then difficult to get it off for the final polishing.  I've
used up to 12 micron grit on pads with good results but it does
tke some time to get the grit out of even the pads so that CeO
can be used for the polishing.
Please note that the purpose of pads is to just shorten the time
it takes to get the glass into the polished condition.  Dale
Eason's photo of a surface is fairly typical of what is obtained
and it takes only a short while to smooth that surface out to a
nice smooth surface that one can be proud of.  Pads are intended
to be used fast and furious as the eyeglass industry uses a lot
of pressure on the pads to polish up the glass surface that they
do.  So put your back into it and press down and move the glass
fast, strokes per second rather than strokes per hour, and the
surface will shine in short order.
With pitch, you can change the ROC by a lot as you proceed with
polishing (I had one guy move a 30"ROC by an inch on a 5"
surface!) while pads will just evenly keep on cutting all of the
surface to the same ROC all the way through the glass if you go
that far.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net


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