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Polishing small areas

I am making some silver or silver and gold pendants which have
several stones set in bezels on the flat surface. When these
bezels are close together, say 2 or 3 mm, or in a cluster, I
find it extremely difficult to get rid of the firescale near
them. Usually I use the bobbing, tripoli and rouge system, with
a polishing machine for the larger areas and a Dremel tool for
the smaller areas. Would anyone have some ideas about getting
into those small areas without damaging the bezels or leaving
bumpy surfaces? Are there specific brushes or wheels etc. that
work well? I really like that polished finish rather than a
brushed, satin finish which I know would be easier. Thanks for
your help.

Sue Danehy, Northern New York State where the leaves are
threatening to turn colors soon.

Hi Sue, I have been working silver for over 20 years and just
recently discovered Pripps fire scale flux. It has made all the
difference in working on silver. It is easy to make and a little
messy to work with but for preventing fire scale it is well worth
the trouble. Check the archives on orchid for the exact recipe.
Or I’m sure that Peter will pop in and tell us the formula :slight_smile:
Janine in Redding CA.

  I am making some silver or silver and gold pendants which
have several stones set in bezels on the flat surface.  When
these bezels are close together, say 2 or 3 mm,  or in a
cluster, I find it extremely difficult to get rid of the
firescale near them.  

The answer is to not get the firescale in the first place.
Pripps flux is a very effective way to do that. Properly applied
to the silver, your finished soldering operation will leave a
slightly frosted white surface, but without any subsurface fire
scale. It will polish up just fine. And the gold surfaces, if
prepolished, will stay that way. If you need info on using
pripps, let me know, and I’ll email you the article I wrote on
the subject a number of years ago. The short description is that
it’s a flux you make yourself easily and quickly, from borax (80
grams, grocery store laundry borax), boric acid (120 grams, drug
store or chemical supply), trisodium Phosphate (paint store TSP,
be sure it’s the real thing, not a substitute, 80 grams), all
dissolved in a bit over a quart of warm water. The amounts
given are suggestions. It’s the 3:2:2 ratio of the chemicals
that’s important, not the concentration. The amounts given will
give you a highly concentrated solution. You may prefer more
dilute. You apply it to somewhat heated silver parts with a
mouth atomizer (a sprayer used to apply ceramic glazes) so it
forms a uniform white crusty coating over the whole silver
surface. This is, of course, extra prep work before soldering.
but it will more than reward you in time saved with the fire
scale that it completely prevents. It’s not really a very good
soldering flux, so you’ll need just a little soldering flux at
the seams themselves. Just take care not to use flux outside of
the seam areas, to avoid disturbing the pripps.

One additional note regards flux. If you are using the white
paste fluxes, you should note that while these are very effective
at promoting solder flow, they ALSO seem to accelerate the
formation of fire scale both on silver and gold. Use of the
batterns self pickling type fluxes, (green yellow liquid fluxes)
while not as agressively active as a flux, will not have this
effect to anywhere near the same degree. If you’re finding the
worst fire scale to be right next to your solder seams, and
you’re using a paste type flux, switching to the batterns type
may solve your problem.

Hope this helps.

Peter Rowe

Dear Sue,

I make a small diameter felt wheel with the abrasive in it
for polishing & cutting. It is mounted on a mandrel for use
with Dremel tools. It works very well . If your interested
let me know what  size ( Diameter) you would need. I'll give
you pricing. 

Bill Zomro

Hi Michael - As a matter of fact, my own personal love for small
spaces is the unmounted soft brisltle brush. Most all suppliers
of tools carry 'em and the arbors they’ll need (they also cost a
lot less that mounted brushes). The other love is one to be used
with caution: rubber wheels, the soft blue or pink ones (if
you’re working on gold or silver). They shape to just the right
contour with a stone block. For those amazingly tight corners,
tho, patience and toothpicks. Chop a toothpick in half, insert it
into the flexshaft, add a little trip or rouge and those nasty
corners are history. The other item to try (I haven’t, not yet!)
is the nifty abrasive floss that I believe is found in the Rio
Grande catalog…there’s soooo many options that a little
experimentation will lead you to just the right tool for almost
every tight spot.

Here’s another idea…take a small drill bit in the flex shaft,
run it through a little cotton pulled from a cotton ball and then
use it like a small, but sturdier Qtip. You can use any kind of
rouge or polish you want with it.

Laura in MD

I do this too, Laura, but one thing that anyone that uses this
technique should be VERY careful about. Make sure there’s still
a pad of cotton all around when you do this, or you’ll get nasty
marring that’s worse that the original firescale to get rid of!

Kat Tanaka

   The answer is to not get the firescale in the first place.
Pripps flux is a very effective way to do that.  Properly
applied to the silver, your finished soldering operation will
leave a slightly frosted white surface, but without any
subsurface fire scale.  It will polish up just fine.  And the
gold surfaces, if prepolished, will stay that way.  If you need
info on using pripps, let me know, and I'll email you the
article I wrote on the subject a number of years ago. 

Well, several people wanted that info, so I dug it out of my old
files again, and may as well repost it now, for those to whom
this may be new. I first posted this, I think on the newsgroup, back some time in '95, I think…

      Pripps Flux

Pripps flux is a mix you make up yourself, and does pretty much
the same as a borax coat which is the older more traditional
method. Classic silversmiths would often go through several
sequences of “burning on” a borax coat before annealing or
soldering, but it doesn’t work quite as easily or as well as
Pripps. I’ve been a gold and silversmith since college, and
learned Pripps from prof. Fred Fenster at the univ. of Wisconsin,
who proclaimed in that 1972 sophomore class that at other schools
people sometimes complained about fire scale, but “here at U.W.
it never gives us a problem”. This, by the way, was taught from
the first moment we were shown how to light a torch, just to
give you an idea of how important/basic a technique Fred felt it
was. It’s named after Jack Pripp, who taught at Rochester for
many years, and is considered one of the “fathers” of the
american metalsmithing community.

The recipe: A quart of water, 120 grams boric acid, 80 grams
each TSP and borax. Boil to dissolve (you might have to add a
little more water… It’s the 3:2:2 ratio that’s important, not
the concentration.) The Borax you can get at the supermarket,
in the laundry area. Borateem is just borax. The little green
flecks they put in there too don’t seem to matter. TST
(trisodium phosphate) is a strong cleaner/alkali often used in
cleaning walls and the like before painting. You can usually get
it in paint or hardware stores, but be sure it’s actually TSP.
Because it’s rather a caustic (though still reasonably safe)
material, some stores carry a substitute, which may be
confusingly labeled. Read the box carefully. The substitute
doesn’t work. If you happen to have a chemical supply house
around, you can also use Disodium or Monosodium Phosphates. But
the Trisodium formula seems to be the most common.

You apply it (and this is an important detail) by spraying it on
the silver while gently heating the silver up enough so the spray
dries on contact, as opposed to hitting as a liquid and
bubbling/boiling off. The best sprayers by far are the cheap
little two-tube-with-a-hinge mouth atomizers that ceramics folks
use for applying glazes. It gives a much finer and more uniform
spray than any sprayer bottle I’ve seen, and cannot clog. In
use, you’ll gently brush the metal with the flame, then in quick
short puffs on the sprayer, put the Pripps flux on a little at a
time. The idea is to coat the entire piece with a thin (thick
enough so the metallic reflections of the metal are no longer
visible, but not more) white crusty coating. Be careful as you
do this, not to either let the metal cool so much that the flux
stays liquid (it doesn’t coat evenly then), or the metal gets so
hot that it starts to discolor. Its easy enough, but takes a
little practice a first. You do all parts of your assembly, then
let cool, set up the joint, and with the addition of the
smallest amount of additional soldering flux only in the joint
(see below) and solder, do the soldering job.

Pripps is a much less “active” flux than the paste fluxes, and
doesn’t burn off easily (though with enough overheating you can
do it), so it gives continuous protection, and thereby completely
prevents fire scale. It will work as a soldering flux all by
itself IF your metal and solder are both completely clean before
you start, and if your “heat control” is good. Paste fluxes
such as “Handy” or Griffin, oddly enough, seem to provide little
or no fire scale protection. If fact, with some metals (like
white golds) you’ll find the fire scale is worse where the flux
was. This is why you don’t want to use much, and keep it only in
the join area. But they are so very active while still fluid and
"there" that they greatly promote solder flow, so many of us use
them anyway. Batterns self pickling flux is somewhere in
between. lasts longer, works fairly well, doesn’t give quite the
fire scale problem, but also doesn’t protect quite as well. In
my work, for simple repairs to already made silver jewelry, I
usually just use a boric acid/alcohol coat, solder with paste
flux, and clean up later, as most of these pieces usually already
have fire scale, and for a single quick ring shank solder job or
what have you, it’s not worth the trouble to bring out the
Pripps. But if I’m making something from scratch, with a few
exceptions, then every last annealing or soldering step is done
with pripps coating everything. The added time and bother is
more than paid back when it’s time to finish the piece, and
there’s no surface oxide and no fire scale, and the piece can be
polished out with the ease of gold work…

By the way, the coating, if you are careful and don’t pickle it
off after soldering, can usually last through several soldering
cycles, so for some complex assembly, if you’ve got everything
fitted before hand, you may only need to coat the parts once for
a number of sequential soldering steps. Also, since the sprayers
tend to cover rather more area than just your silver (like tools
and bench areas behind your soldering area, you will want to set
up some sort of simple shield behind the area you’re using for
spraying on the flux to catch that overspray. Saves a lot of


Peter Rowe

Hi Michael, I gather that your main problem is the firescale
itself. If you soak it in pickle solution for a bit an end brush
with tripoli should remove it with ease. As far as getting a nice
even area around your bezel, that may result from too much solder
around the head. Having made that mistake, I used a rubber pumice
wheel to help in cleanup. If all else fails sand blast finish
with high polish heads does make for an attractive finish on
some pieces. Hope this helps.

Michael B

Some of my tricks for polishing small areas: Use a loose musling
buff, first with White Diamond (a tm polish compound), then
Fabulustre. The loose threads get into small spaces and recesses
without taking the top off the high spots. Another is to burnish
with crimped wire brass brushes before setting stones. If
sterling, you may have to bring up a fine silver finish by
oxidizing several times, pickling, then brass brushing. The
third trick is handy and old. Take cotton twine, clamp one end in
a vise, pull the other end taut with a hand. Bob the twine with a
greasy compound by stroking it back and forth along the twine
until the twine is loaded. Take your piece in your free hand and
move it back and forth quickly on the bobbed twine. You can also
clamp the piece that needs to be polished and use the twine like
you would use a rag to shine shoes when you’re putting on the
final buff. Anyway, this method is called “thrumming”, because if
you’re doing it properly, the string will “thrum” when you’re

K. Palochak

I like to use a toothpick. Cheap, and easily replaced. And will
not leave scratches in the materials while polishing. Sometimes
the wood actually holds the polish compound and gives a good
finish also. (I use this to polish small stone seats after
cutting with the bur. It gives a mirror finish.)

Hi Michael,

The firescale is something you can avoid by using boric acid and
alcohol. I clean up tiny areas that can’t be reached with a
magnetic tumbler. If not that little stiff brushes will snap down
in a recessed area better than soft. If not that a toothpick in
your flexshaft with the end frayed a little with polishing
compound on it.

Mark P.

Dear Michael,

I would use “Water of Ayr” stones. These are also called
"Tam-O-Shanter" Stones or more commonly (at least in the U.S.)
“Scotch stones”. They are a fine slate-like square rod,
available in various sizes from smaller, older style jewelry
tool suppliers (try Gamzon Bros. in N.Y.). You can grind the
end to the shape you need on a standard grinding wheel. Wetting
the end that you have shaped and rubbing it on the area that is
firescaled, you will abrade the offending firescale off in a
controlled manner. These stones leave a 600 to 800 grit finish.
If you use a larger, rather than narrower, width stone during
this rubbing, you can avoid leaving shallow waves or surface
aberrations. Try to rub in different, i.e., 90 degree,
directions and it will also help avoid these depressions from
forming. But Peter Rowe is right, avoiding the formation of
firescale in the first place is the best alternative.
Hope this helps, Eben

Kat and Laura: its alot safer to use a toothpick which will grab
into a cotton ball also to make a sturdier Qtip type polishing
tip. You can also use a toothpick by itself with some polishing
compound on it. Its slow that way but if you use some lighter
fluid to help the polishing compound sink into the wood it helps.
Bobbing compound works fairly well with toothpick only…As for
me I try not to design things that are too close together to make
setting stones difficult or polishing difficult, its just not
worth it sometimes, especially if you’re doing silver

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