Soldering 18K & Sterling Your expert advice

Jewelry Discussion
1

Hi All, I have a project which requires soldering cast 18K pieces
onto a sterling silver sheet.

It’s tricky soldering, and in the past, when soldering lightweight
parts, I’ve had the misfortune of the gold melting into the silver
right before my eyes! and I definetly want to avoid this happening
again. Since the silver sheet is more massive than the gold part
would you recommend using gold or silver solder? Is it the silver
solder that eats up the gold? ( so to speak) or does the gold solder
eat at the silver??

One of the projects, and the one which concerns me the most, is one
of those BiiiiiiiiG Oval Cowboy Western Belt Buckles. The kind G.W.
Bush wears!! The center will have a detailed18K cast piece soldered
in the center and this guy wants 18K ROPE wire on the edge. Since no
one sells rope wire in 18K, I’ll have to make it…in approx 8
-10ga. I’m not certain how to calculate how much I need for the
twisting??? Is there some formula? AND…it’s going to use a TON
of solder to nail it down to the surface of the Sterling sheet.

I was also thinking I could make the rope edge trim from Sterling
stock, shape and solder it, file the underside flat, have a mold
made and cast it in 18K and then solder it in place. Does this seem
like I’m loosing it? Is there some simple new technical way I can
make this in both metals in a simpler way? I see all these bimetal
rings etc that are cast, but I am not familiar with the technology.

Can anyone help or offer advice?

Thanks,
Mary Ann Archer

2

Mary Ann,

You might consider doing the wire rope with wax wires to get your
casting. The wax is much easier to bend in the gauges you mentioned.
Then plow a channel 1/4 to 1/3 of the diameter deep into the wire to
fit over the edge of the Silver plate. Think “C” shape. Position it
onto the plate then solder the ends and tack at several points
around. This would be far easier than trying to tack down a twisted
wire all the way around on the edge.

Bill

3

Mary Ann Archer,

Having made a few thousand of these over the years… I can tell you
the following:

An 18K casting is normally soldered onto the base plate of sterling
with silver solder.

Here’s where the professional does it differently. We do not use 3
to 5 grades of solder to put one of these together.

One grade, for example medium, is used to put the rope edge, the
central motifs, banners/lettering, and flapper backs on. The reason
being that if you have proper control of your flame, set the pieces
in proper jigs, nothing will shift or move. Each time you heat a
solder joint, the alloy changes slighty - making it just a tiny bit
higher temperature than “fresh” solder. This continues throughout
the piece…

You can purchase 18K round wire from several sources. Then twist it
with a hand drill and screw eye. We generally use 14 to 16 gauge
depending on whether the rope is soldered onto the edge or laid on
top. 8 or 10 gauge sounds rather heavy, unless you are measuring the
finished twisted wire. (Or it’s a VERY big buckle:)

Casting from a twisted wire model can be done, but by the time you
make it, mold it, shoot a wax, burnout, cast, and cleanup - I would
have assembled the entire buckle, prepolished it, engraved it,
finished the final polish, cleaned and boxed it. If you’ll give me
the dimensions of the buckle I can look up what we normally allow
for twisted rope that size.

Or, if you decide that it all looks too daunting, send me the parts,
I’ll give you an estimate, and we’ll make it for you on our next
"run"…:slight_smile:

Brian P. Marshall
209-477-0550 Workshop/Studio
209-957-6157

4 
 I'm not certain how to calculate how much I need for the
twisting???

Why don’t you just try twisting up some brass of the same gauge;
measure it BEFORE twisting it up with a magic marker; it will be too
hard to do after the fact. The practice will also be good for you
prior to tackleing it in 18 K.

A different course would be to Check out Rio and Indian Jewelers
Supply as the last time I was in New Mexico I picked up some sterling
heavy gauge twist wire that had a 1mm grove cut half way through it.
I’m not sure how it was made but it is intended to exactly this very
usage, it goes on the rim of what I call a Rodeo Buckle. I feel like
it looks nicer when it really is on the rim (edge) and not merely
sitting on the front of the plate. Maybe you could cast some of that
grooved sterling into 18K. Good Luck Mark Kaplan

5

Hi Brian, I spoke to Maury Cain and just today sent him the drawings
for images to put on the belt buckles. Once he sees them, I will have
a time table etc., and when carved, he will send you the original
model for you to cast.

I would like you to cast it in sterling and then send it to a man in
CO who will be doing the CAD work. He will be making two different
models, sizes, depending on which one Maury carves. Altogether, I
need three models, three molds, two belt buckles and one pendant. The
smallest model for the pendant is something I will be doing entirely
here in my shop. The two belt buckles, I have decided to have you
make.

I am definetly considering having the logo cast in a lower karat
gold, as you mentioned. This makes the most sense for cost and, like
you said, wearability. I was beginning to get a bit nervous about the
cost for the 18K and thinking the client would drop the whole project
if too costly. And to keep it more authentic, I like the idea of the
engraved background. I need to get in touch with my clients who are
on vacation, but we have time.

What do you think it will cost to make these two buckles in 10K gold
and Sterling and do the engraving? Also, you would be making two
vulcanized molds for the logos, for I may need them in the future.

One thing I was thinking about and mentioned to Maury is that a belt
buckle like this is not flat and so, should he carve this on a
curve??

I’m attaching the same drawings I sent to Maury, so that you can see
the sizes.

If the attachment doesn’t come through, let me know and I will send
it in a different format.

Mary Ann Archer

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