18K Pd plumb solder will not flow

Hello, All;

I am working on a pair of commissioned wedding bands that are 12 x 1
mm, sizes 10 and 5.5, in 18KWPd. The 18KPd plumb solder will not
flow. I am using Acetylene with a Prestolite torch, on a charcoal
block, and have tried black (1800 degree) flux, boric acid with
alcohol and proprietary flux from Frei and Borel. I ball up the
solder using flux, heat the metal to cherry, place the solder and
nothing happens. I must admit that I am somewhat uncertain as to
what the metal should look like at the correct temperature

The plumb solder is said to flow at 1840 degrees, and I guess that I
am probably getting about 1800 out of the acetylene. Do I simply not
have enough heat? is the capability of the torch the limiting
factor? Should I just break down and move on to another fuel and
torch? What would be recommended?

Several years ago I did a similar project with difficulty, but I
finally prevailed. Those rings were slightly smaller, but the same
everything else. In the present project I am cleaning the metal with
a scrub pad and Bon-Ami, and rinsing in water with baking soda.

Please, please, please, can someone help me? More than a few hours
in the studio with nothing to show for it but my frustration.

Susan Ronan
Coronado, CA

You are probably not getting the ring hot enough to melt the solder.
Pd really pushes the melting point up. Try a piece of scrap material
and see if you can get the solder to flow on it. Also as a word of
warning there is a significant difference in the amount of palladium
in white golds from different suppliers. and this can lead to
melting the gold if the solder you are using is not formulated for
the Pd White you are using.


Hi Susan, 18KPdW is heaven to fabricate but to solder, I had to get
over my fear that it would all melt into a lump any second. I use
Platinum solder for the first (shank) joint and heat it past cherry
to day-glo orange before the solder flows. The Pt solder I use flows
at 1100 degrees C; the 1840 degrees F flow temp you’re looking for
translates to about 1000 degrees C. I finally got comfortable with
the day-glo orange through a different exercise: I melted some 18KPdW
scrap to roll out for reuse. Try it and see how long it takes to melt
when you’re TRYING to! (I’m using a propane/oxy Little Torch.) It’s
also possible that you’re using too much flux in an effort to protect
the piece from the high temperature. This heavenly metal doesn’t
oxidize and I only lightly flux the solder and the joint, not the
piece. It’s very nice stuff to work with; you’ll love it after a
short learning curve.

Hope this helps a bit,
Linda in MA, where spring hasn’t moved in for sure yet

If you are using Hoover and Strong’s 18k palladium white solder, I
can tell you that we, too, have a hard time making it flow (and we
use an oxy acet torch which is much hotter than yours). Perseverance
helps, but we sometimes use either 14k palladium white solder or
regular 18k white solder (if it is on a spot where the color
difference won’t matter).

Daniel R. Spirer, GG
Spirer Somes Jewelers
1794 Massachusetts Ave
Cambridge, MA 02140

Hi: What you are dealing with is called a eutectic point.soldering
white gold to yellow often encounters this problem and there is a
solder made to flow in these conditions… A titanium probe used to
bridge the gap can work also. you could also be dealing with
carbonizing the joint if your flame is not correct… oxyaceteylene
can heat well above 2000 degrees and melts platinum so i think that
is not your problem…a paste flux may also help… Ringman