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Polishing tricky area


#1
In soldering previously polished area there are 2 primary issues
to deal with. 1. To avoid "gosting" ( traces of melted solder ). 2.
Preserve original finish. 

I can fully see how meeting the requirements of both issues, #1 & #2
above have an effect on the final outcome of the soldered piece as
to the state of the polished surface. My techniques address both and
include the careful application to produce a oxide preventative
barrier with boric acid and alcohol.

Where we depart in procedure is the use of easy solder. Many of the
pieces require multiple solderings of hard, medium and sometimes
easy. The easy has a great tendency to flow into unwanted areas
regardless of technique, amount of solder used, or use of any of the
solder stops available. I avoid the easy when possible.

The polishing technique is understood to be important to the process
as well. Acquiring a good polished surface has not been a problem.
The true problem is maintaining the level of polishing on the piece
after soldering where it requires absolutely no clean up afterwards.

regarding the “beilby layer” you suggested I google, this was done
and the varying results were mostly not pertinent to the discussion.
In fact there was some decidedly conflicting A less than
encouraging view was given by AZOM, a metallurgical site for
http://www.azom.com/details.asp?ArticleID=1511

“The presence of amorphous metal was widely accepted in the 1930’s,
mainly as a result of work by Rosenhain, and his powerful support of
it using his great skill in debate. This did not lead to any
significant advances in polishing techniques and was eventually fully
discredited.”

To avoid such conflicts in about the “beilby layer” and
to better understand the polishing process, I must ask if I may
prevail on you to give a general overview of the polishing procedure
as you understand it in order to arrive at the soldering with
absolutely no clean up afterwards.

I appreciate any you can give.

J Collier
Small Scale Metalsmith
http://jlcollier.com


#2

The reason I mentioned easy solder is because assembling of polished
components is the last stage. Also, pieces to be assembled must
engage mechanically. The solder is only playing part in preventing
disengagement. The structural load is carried by the joint design.
Then the small amount of solder is absorbed by the joint and will
not flow second time.

To understand Beilby layer:

Polishing is accomplished not through the process of abrasion, but
through the smoothing the surface irregularities via heat and
pressure generated by polishing wheel. The result is a very thin
amorphous layer which is called Beilby layer in honor of the
scientist who first proposed it’s existence. If we polish an article
via tumbling, or using modern hi-tech wheel, the Beilby layer cannot
be achieved because these methods using very fine abrasives but do
not generate heat and pressure required.

The best wheel for obtaining quality polish is walrus skin, but
nowadays it is probably illegal to buy one.

Lapidaries are very familiar with Beilby layer. Cerium oxide is
primary polishing agent in polishing Amethyst but it’s hardness is
much lower.

When we evaluate quality of the finish on the gemstone, we evaluate
quality of Beilby layer.

Leonid Surpin.