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Polishing Problems


#1

Hello! I learned of this sight while attending a wax carving course
at the New Approach School For Jewelers.(Kate Wolf) I have been
having a problem with polishing silver, in that, I can’t seem to get
the mirror finish I want, especially on flat surfaces. I’ve tried
every compound I can think of and I still get this
"static-on-the-television-screen" look. If you can help me with this,
I and my customers would be most greatful! You have a great sight,
and I hope to be able to make a contribution to your bench tips soon.
Thank you very much! Kerry Smith


#2

Hi Kerry, You problem may be fire scale. If you experience the
problem on silver soldered work there are fluxes on the market that
will prevent fire scale when soldering. Fire scale forms whenever
sterling is heated about 1000 degrees. It can only be removed with
abrasion or chemical stripping. It is best to prevent it. Other
problems on cast work that might cause problems are pitting in the
metal due to oxygen absorption, poor burn out or waxes that are not
smooth. There are many post concerning any of the above problems. If
you would like a more detailed description contact me off line and I
would help in describing the possible problems.

Your Orchid Friend
Lee Epperson
602-993-4766


#3

Kerry, Here’s the process that I use (I’m self-taught: books and the
web):

  1. Garden-variety sandpaper (there’s a Lowe’s very close), starting
    with 150 grit (mostly for shaping and removing or flattening). Then,
    going perpendicular to the scratches from the 150, I use 220 grit
    until all of the 150 scratches are gone. Then I use 400 grit, again
    going opposite to the 220 scratches, until all of those 220
    scratches are gone. The last step with sandpaper is with 600 grit,
    going against the 400 grain, until all of the 400 scratches are gone.
    (If you look at your piece as having a “top” and a “bottom”, a
    "left" and a “right”, I go “top-to-bottom” with the 150 and 400, and
    "right-to-left" with the 220 and 600). I can only find up to 600 at
    the hardware store, but you could continue on with finer grits (800,
    1000, 1500) if you can find them. And, if your piece doesn’t really
    need any shaping, you could probably skip the 150 grit (although once
    starting, don’t skip a grit (like from 220 to 600)).

  2. I then switch to the flexible shaft (or dremel). I use felt
    buffs (Rio Grande has a pretty good selection on p. 163 of their
    "Tools & Equipment" catalog) with White Diamond, typically making 3
    or 4 full passes over the piece.

  3. Clean the piece of all of the White Diamond.

  4. I then switch to Tripoli, still using the felt buffs. Another 3
    or 4 passes over the piece (or to when you like the results). Then,
    still with the Tripoli, I switch to a muslin buff, and use that for
    another few passes.

  5. Clean the piece of all of the Tripoli.

  6. Using a chamois buff, I then polish with Grey Rouge, this time
    only making 2 passes.

  7. Clean the piece of all of the Grey Rouge.

  8. Finally, with a chamois buff, I finish the piece with a couple of
    passes with Zam.

  9. Clean the piece and I’m usually done.

I’ve had very good results with the process, although some of the
other members of this list may say I’m over-polishing. But, I am
getting that “mirror” finish on my silver…

With the buffs, I try to use very light pressure and keep the piece
moving all of the time. Even though these compounds are very lightly
abrasive, they are still “abrasive” and could wear a groove or a flat
spot.

One other note, make sure to use a fresh buff/muslin/chamois piece
whenever you switch polishing compounds (the White Diamond, Tripoli,
Grey Rouge, and Zam). You won’t get the results you want otherwise
(I’ve always used new ones, so I can’t be specific as to what would
happen).

Good luck!
Jon
{hey, I finally got to contribute something! :slight_smile: }


#4

Dear Kerry, I have found that the only way to get the mirror finish
is to have filed and emeryed the surface first. On a flat surface it
is very difficult to get the kind of filed and properly emeryed
preparation necessary which even the slightest dome will allow. I have
also learned how aggressive rouge ( I use red) can be. Rouge is not
a substitute for tripoli and white diamond which is my usual course
but, let the rouge work. Keep a constant motion in all directions
while filing, emerying and all courses of polishing, cross hatching
is what I call it, and watch that the last file, emery and polishing
compound marks have completely disappeared before moving to the next
course. Sam Patania, Tucson-


#5

kerry, first, make sure your buffs aren’t contaminated with the
other compounds your using.(dirty hands can cantaminate) second, turn
silver as you polish polishing in one direction can cause this haze
look third, i use green and or black rouge for silver it seems to
work for me fourth ,if alan revere has a tape on polishing, buy it it
will pay for itself in the time you’ll save good luck. lisa
mcconnell ps if ar doesn’t have polishing tape he does have books on
repair and goldsmithing polishing classes are short take a week
end and go to san fran food for thought lm


#6
 problem with polishing silver, in that, I can't seem to get the
mirror finish I want, especially on flat surfaces. 

My understanding is that traditional European apprentices can spend
a year, or more, just on this one aspect of the craft… before they
get to do anything fun.

On silver, I “always” use the finest abrasives followed by tripoli
and rouge. Interestingly, I have a monumental piece I’ve finally
finished, and wasn’t happy with the polish. Went over the whole thing
with Zam and was surprised to find the results were superior. Was it
just due to the additional polishing time, or did the compound make a
difference? Hard to tell.

Flat surfaces are especially challenging. Once you get a ripple,
gouge or depression on a flat from a polishing wheel, you’re sunk.
You either have to live with it, or go back and re-sand to flat.
Continued polishing with a buff will only aggravate the situation,
and will never fix it, increasing frustration. The problem stems from
trying to polish a flat surface with a round, rotating wheel. The
smaller the wheel (like on a flex shaft) the worse it gets.

Ideally, flat surfaces are polished on a flat lap. Usually hard
felt, often a “split lap.” A split lap has radial slots cut through
so you can see the work somewhat as the wheel goes around, and you
are holding the work to the flat underside.

Choice of buff material may also have a bearing. I use one of those
"stringy" mop buffs for something with surface relief, so the little
strings can get into the texture, into corners, etc. For flat, convex
or more uniform surfaces, I tend to use a solid felt buff.

I do a lot of the delicate polishing on my flex shaft, reserving the
big buffer for larger pieces or those that are not prone to being
snagged. The last thing I want to have happen is have a piece
destroyed at the last moment by the power of the big buffer. Has
happened… :frowning:

As with the thread on stone polishing, you’ll never get a fine
polish on a poorly prepared surface.

Hope this helps,
Dave
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com


#7

Are you using a firescale preventer such as Prips Flux? When I tried
to use this, I determined that I was too careless to get a good even
coat of it because after pickling, I had a spotted look that you
might describe as TV static.

Marilyn Smith


#8

Hi Kerry, The problem you are having with the "static screen look "
when polishing is not due to a problem in your polishing methods…
it is a problem directly in the metal. If the item was cast, then it
may have been sprued incorrectly and it was probably cast too hot
either in flask temperature , metal temp …or both and all the
above… If the item were hand fabricated, and items were soldered to
the sheet , then the problem may have caused by overheating in the
soldering process…

If you were to take the piece with the problem and try to file it
out with files and sandpaper…and if it still reappears when you go
to polish… then it is in the metal and due to one or all the
statements I made above… there is nothing you can do to polish it
out… you have to make a new one and make sure it is done
correctly.

Best Wishes, Daniel Grandi We do casting/finishing/enameling ,
soldering, cnc models and hand made models as well as a lot of other
processes for designers and people in the trade.


#9

Marilyn, Long time ago I read how to more evenly spread Prips flux.
Get hold of a nasal push type spray device and fill it with the flux
solution. this sprays a very fine mist that evenly covers the work.
Teresa


#10

I liked Jon Lowe’s explanation of the polishing process but wanted to
ask about one point. After sanding he uses first White Diamond and
then goes on to Tripoli and rouge. Now I had thought that Tripoli is
more aggressive than White Diamond.

The stick or bar type polishes are generally an oxide powder
embedded in a wax-like carrier, so my question comes down to one of
grit size of the powder. Does anyone have or know of a reference to
a table of grit sizes for the common pre-polishes and polishes used
for silver?

My assumption from various company catalogs and past posts is this
list in order of decreasing grit size.

Bobbing Compound Tripoli White Diamond Zam Red Rouge

Black rouges and Grey rouges are also mentioned for use on silver.
Does anyone have experience in using them?


#11
Marilyn, Long time ago I read how to more evenly spread Prips
flux. Get hold of a nasal push type spray device and fill it with
the flux solution. this sprays a very fine mist that evenly covers
the work. 

Try heating the metal slightly before spraying on the flux unless
the solution has alcohol in it. If the solution is water base the
metal should be hot enough to evaporate the water as the spray hits
the hot metal.
Lee


#12

I did this very thing and still have it sitting around someplace. The problem
is that it clogs up very quickly! If I used it every day, I could probably
keep it functional but alas, I don’t. I tend to mistreat my metal as I
work and usually wind up doing sanding and even filing when it is finished.
This ruins any nice fire coat that I have built up. I know my faults but
don’t change them. What can I say?

Marilyn


#13

Dear Dave also tried Zam it worked Wonderful… Also the new German
rouge is great…calgang


#14

Kerry- I am still learning too, but I have gotten a “static look” on
my work that turned out to be too much compound that wasn’t coming
off easily after the polishing step. I could dissolve it with
lighter fluid (which I used to wet the buffing wheels before
charging with compound).

J. S. Ellington


#15

J.S., I would be use caution when using lighter fluid around a
buffer.They generate static all the time especially in dry climates.I
get shocked every time I walk up to mine.A spark could ignite the
lighter fluid if the container is open or if you are drenching the
wheels with fluid. Regards J Morley Coyote Ridge Studio