polishing

[Norman Watts <Norman_Watts@zzzzzzz>]

V.T.

I liked the polishing article as well, but unless I missed something
he still didn't explain some things, such as why you would choose
water or oil as a lubricant. He also focussed on work with glass,
which is a super-cooled fluid not a crystal, so the mechanism is
bound to be very different in stone. Also, I'm still curious as to
what polishing actually is. Sure, its approaching a finer and finer
surface, but so what? I'm not sure what is happening, at several
levels. What is going on as the smoothness gets well below the
resolution of the eye, ca. 0.2 mm, but still rough on the microscopic
scale? Scattering is occurring from distinct areas but you can't
resolve it, yet it looks dusty. Why is that? I can't ray trace that
at all. In fact, it occurs to me that I don't really know what
reflection is at the next level down either. I think the mechanism of
reflection from metals (with free electrons throughout) is
fundamentally different from the ionic or near ionic bonds in
crystals. In metals the emitted photons may not be the original
photons (if you could tell them apart). As for the effect of wax and
water. I don't understand that either. Do these work by reducing the
refractive index difference at the air-surface interface? A light
wave originating from an electronic plane within the crystal will be
strongly affected by the change in refractive index as it is emitted
into air. Maybe hydration of the surface atoms changes their
behavior. This is all speculation, but it just shows me that there is
a lot going on that one never thinks about. Somebody must know this
stuff, probably in the optics and coatings industry.

n