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Question on Spharex


My name is Fred, and I am a bladesmith, as opposed to a jeweler. I am
trying to branch out/up in my making of furniture ( ,that is,
fittings such as handles, guards, pommels, ect. on knifes and swords
). In particular I am working towards setting of stones. Currently, I
am starting out with Alloy 510 Phosper Bronze to try and make some
fittings. I am starting out with this alloy because is seems to be a
cheap metal to learn with as opposed to gold and silver, and I have
around 500 lbs of the stuff seating in my shop in every conceivable
form ( sheet, wire, bar stock, hex stock, … ).

The current problem I am having is with soldering. Typically, in my
work, when soldering/brazing/welding one starts with an oversized
piece, does the hot work, and then grinds off the scale and other
crud. I finding that working with the smaller material presents a
problem there is not enough meat to grind off. In particular, when
soldering the phosper bronze sheet and wire, as you can not grind it
when done. What I am trying to get rid of is a copper bleed through
from the base material. I not sure if this is the tin being burnt out
of the bronze, or the copper in the bronze coming to the surface due
to the heat. I am using Safety-Sil 45 silver solder ( 45% Ag, 30% CU,
25% Zn ) from J.W.Harris welding supply company ( a good color match,
1370 F solder ) with their recommended brazing flux ( Whit Stay-Silv
Flux ). I am using a rich flame on the O-A torch. It is not the
solder joint that is the problem, per se, but the surrounding
material. I was told by a gentleman on the sword forum ( same as this,
but for bladesmiths ) that jeweler run into this same problem all the
time and use a solution of spharex, sulfuric acid, boric acid, and
hydrogen peroxide to pickle the copper out.

Three questions:

  1. Is the correct solution?

  2. What is spharex, where can I get it? I have done web searches to
    no avail.

  3. Any hints on setting stones? I have broken the last three when I
    have hammered down the bezel.

Thank’s, Fred ( @JYBlood ).

Fred- I think what you are looking for is “Sparex”,a pickling
compound made of sodium bisulfate. You can buy it from any jewelers
supply company or go to any store that sells pool and spa supplies. It
is used to lower the PH. A word of caution- NEVER put ferrous metal in
a pickle bath. For your firescale problem I would try a solution of
boric acid powder mixed in rubbing alcohol (about 70/30 solution
should work) and paint it on as thick as possible then burn it off.
The boric acid should create an airtight coating. Good luck !


HAVE A NICE DAY. john Henry

one more thing… check jewelry supply places… (internet sites
would include… or on the phone ,you
can try…Iowa jeweler supply 1-515-243-3189 they should be able to
help with chemicals that are mostly used in jewelry work… recap
(real quick)

  1. firecoat…this is boric acid and alcohol (used before piece is

  2. pickle …sparex and water (used after piece is heated)

ok, have a good day…

fred, what you are looking for is sparex…this is used to take off
the firescale at the end of the soldering/brazing/welding. However,
you can also use a firecoat before heating which will also
help…this is usuallya mixture of alcohol and boric acid. (some
supply shops even sell a “blue alcohol” which is a combination of a
firecoat and a flux. The firecoat does help alot in keeping the
copper bleed through on gold down) maybe also try a different or
softer flow of solder to keep your heat on your piece down, hence the
copper bleed down) as far as bezeling your stones, let me give you
some suggestions…

  1. make sure that the seat for your bezel is clean of any burs that
    may break the stone (what type of a bur are you using…for cabs,
    use a round bur…for faceted, you would want to use a 90 degree
    hart bur (coloured stones, and you may need to go in with a ball bur
    if the girdle is particularly thick) diamonds use a 45 degree hart

  2. to peen your bezel down, either use… a burnisher…which us
    usually a slow and arduous process personally I prefer to use a hammer
    handpiece that is available for a dremel tool.

if you are bezeling soft stones I would recommend that you make the
bezel wall as thin as possible (less bezel to peen) sometimes after I
cut my seat and I have a problem getting the stone in I cut a bearing
in so where the stone would seat is a thinner wall than the rest of
the bezel (this would probably come across clearer with some

finishing off the bezels is not very easy either…i usually use my
thumb nail as a block to protect the stone and run a file to smooth
the edge.

Hang in there, and if you have any more questions, maybe I could help
(I would love to see some of your work…I recently purchased a
canyon diablo damascus meteorite blank and am working on how ornate I
can make the hilt…) -julia

NEVER put ferrous metal in a pickle bath. 

Sodium bisulfate pickle is in fact a standard for steel and iron. But
if you are using it for precious metals then introducing a piece of
steel while a piece is in the solution can cause plating on the work
(removed by immersing in a 50/50 solution of household hydrogen
peroxide and picle solution). As far as I know it only plates while
the steel is in the solution and when it is removed all returns to
normal. John B., Peter R. can you correct me? So, if all you are
putting in there is steel and iron it is ok. Charles

Charles Lewton-Brain
Box 1624, Ste M, Calgary, Alberta, T2P 2L7, Canada

Fred and fellow Orchidians

After reading the replies you’ve gotten so far, I’ll try to answer
more than what you asked. Everything following is “My Opinion” I do
believe you will want to use a boric acid fire coat before soldering,
( boric acid and denatured alcohol) burn off the alcohol before
applying flux ( I recommend " Batterns self pickling flux" ) After
soldering, use " Sparex #2 Pickle " it’s formulated for non-Ferrous
metals" However, if you wish to pickle ferrous metals, use ‘Sparex
#1’ If you mean oxygen rich , that could be part of the problem.You
may want to try a neutral flame when soldering, also don’t worry too
much about temperature as the alloy you’re using has a solidus temp.
of 1,787�F and a liquidus temp of 1,940�F which is well above the
solder flow point. Now for your setting difficulties, it could be that
the alloy you’re using is too hard or that the bezel is too thick,
either way I think I need more to help you. ( there are
many other ways to set stones ) I am a Jeweler by profession but
consider myself a metalsmith. I have done bladesmithing as well as
setting stones in blade furniture. And have even set stones in steel.
If I can be of further service to your endeavors, please feel free to
write me.


P.S. I found a nice Material Properties Database at that
could be of use to all.

  Three questions: 
  1) Is the correct solution? 
  2) What is spharex, where can I get it? I have done web
  searches to no avail. 
  3) Any hints on setting stones? I have broken the last three
  when I have hammered down the bezel. 

Hello up there,

As far as I can judge it, you’re having a problem with the cupper
oxidation, and for this purpose you could of cover your working piece
with borax which is fairly cheap and extreem helpful.The borax will
prevend the oxidation of your working piece … for a while !!! So
acurate,clean and a good soldering technic is recommended.

Sparex is a grannulation of several chemicals and is as far as I know
a’s a pickling solution very well know in the United
States and I used it aswell due to the american contacts I have.

Start with cheap stones and/or synthetic stones to build out your
experience.Second, you have to anneal your bezel real good untill is
soft enough to “BEND” the bezel instead of hammering (read

Some video tapes about stone setting are of incredible help and again
… America has it all.

Last but not least …lots of trial and error change a layman into
a proffesionel.

Regards Pedro

It’s called Sparex, and is obtainable from Rio Grande catalogs
(others, too, I’m sure).