What actually happens at the surface of a metal when we do buffing and
polishing? Is the heat generated a requirement or a hindrance? Are we
just refining the surface with smaller and smaller scratches to the
point where the scratches are so minute we call it polished? Or is
there actually some metal flow created by the heat? If someone with a
technical background and few minutes to spare can offer an
explanation I would greatly appreciate the
A few months back, Lapidary Journal had a long discussion and article
about polishing, and its many stages.
Just to answer your questions, to start, all you are doing is
abrading the metal with finer and finer scratches, so that by the end
it is imperceptible to the eye. You do this in stages for several
reasons, one of which is that a uniform surface of minute scratches is
much better than mostly tiny scratches and a few deep, so you go step
by step, smaller and smaller, it produces the best results. For the
final stage, it is actually burnishing the metal. This is rubbing the
surface to a “mirror” finish, and is accomplished with rouge
compounds, with wheels, a buff, a leather buffing wheel, or even a
chamois. Of course, you can also burnish the old fashioned way, with a
burnisher made of either a good stone, or a mirror steel burnished.
But the heat isn’t exactly part and parcel to the process. the heat
can be useful with some compounds, helping it to move, and there for
not clog your wheel, and thus keeping the compound moving, and the
compound that is no longer abrasive, or filled with the metal flying
off of your piece. This is not a bad thing, and for many waxy
compounds, the heat really helps, but you will still have to comb your
wheel. I don’t know that I have exactly answered the question, but I
thought for the most part your observations were accurate. The only
difference is what “rouge” does to your metal. On a last and final
note, I wanted to add that if you do not keep your compounds and
wheels separate, than your rouge wheel will not be burnishing, but
abrading your metal, due to contamination. It can NOT be stressed
enough how important keeping the polishing area in order, and free of
contamination is.
A. Austin
Silversmith
To understand reflection you have to know about the relationships of
electron and light. If you didn’t mean about reflection, please don’t
mind this mail.
What actually happens at the surface of a metal when we do buffing and polishing? Is the heat generated a requirement or a hindrance? Are we
The light is a kind of electromagnetic(radio) wave that human can
perceive. There are many names of electromagnetic wave with its
energy. A little lower energy electromagnetic wave is called
“infra-red wave”. A little higher energy wave is called “ultra-violet
wave”. Higher energy wave than UV is called “X-ray”, and higher than X
is called “Gamma-ray”. The wave length we can see is about from
0.0004mm (violet) to 0.0008mm(red).
Classical mechanics only explains how the reflection occurs, but
cannot explain why. So I like to explain the essence with quantum
mechanics, but only briefly.
A charged particle, in this case an electron on metal surface,
vibrates in the electromagnetic wave (light). The frequency of the
vibration is the same as the wave. When an electron moves because of
incoming electromagnetic wave, it becomes a source of electromagnetic
wave with the same frequency. One electron can radiate only weak
electromagnetic wave. But if many electrons radiate the same
electromagnetic waves, the electromagnetic waves interfere each other.
Then strong electromagnetic wave is created. This electromagnetic wave
created by many electrons is called reflection.
The flatter the surface of the metal (on the order of the length of
light), the stronger the interference becomes. So if you want a shiny
metal surface, you have to polish it on the order of 0.001mm (one
micron) or smaller. Perhaps almost all people think that it’s too
small, but it’s not so small. The thickness of aluminum foil is
0.015mm.
If someone wants to know more or has questions, please let me know.
But the problems of light is very difficult, so I may not answer
difficult problems.
Takashi Tomoeda @Takashi_Tomoeda