Enamels and soldering

Jewelry Discussion
1

Well, I have searched the archives and read the relevant books on
enameling and soldering. I still have some technical questions, so I
am asking those of you with experience enameling to share. I am just
getting into enamels and the texts sometimes lack on the finer
points of fabrication.

I understand the issues with solders containing zinc in areas that
will touch enamels. The suggestion one sees is to use the eutectic
solder. So, I look at the “eutectic” solder Thomson Enamels sells and
it flows at 1460 F - that is not the flow point of the silver/copper
eutectic - which is about 1434 F. If I am firing at 1450 F… 1460 F
make me nervous, and the true=1434 F flow point of the eutectic is
not going to work. What happens here? Does the “eutectic” solder
immediately flow and dilute… raising the melting point… like
granulation? I get using IT for the joins not in contact with the
enamel… but what do you use for the ones that are? I thought about
making my own solder… but don’t understand the copper/silver system
and know the melting temps are not linearly related to the
copper/silver ratios. Is there an algorithm that provides melting
points for various percentages of copper and silver… or a chart??
Anyone fusing sterling or.999… seems like a very small, local and
very hot flame might work. Yeah, I know… I can try that myself.

The texts recommend .999 silver. That makes little sense since you
can enamel directly on copper. Why not sterling? Is this just a
thing with transparents and firescale? If my first application is an
opaque can I use sterling? We are talking about pieces that will
still have a significant amount of metal showing. Obviously, I’d use
copper if covering it all up.

Can you depletion guild a soldered piece? I guess I could just try
that and see what happens :slight_smile: It is feasible to fabricate a piece out
of sterling, depletion guild it… and fire it? If I make a hollow
form using sterling soldered with IT and depletion guild it… will
that work? Or, am I going to make a mess? Will depletion guilding
cover the solder and eliminate the zinc issue? Can I plate it with
fine silver before firing? Can I cover the solder seams with .999
foil when using an opaque? What about the new germanium containing
alloys? I have resisted using Argentium… call me a purist :slight_smile:

Moving on… if I apply Keum Boo to fine or depletion guilded
sterling… will it diffuse into the silver at the short, hot firing
temps of enameling? Obviously, we are talking Keum Boo under
transparents. I know I can apply gold foil to a base layer… but I
lose the metal color then.

Can I enamel over a patina such as liver of sulfur? For instance,
can I apply Keum Boo, use LOS for a patina to get contrast, then
fire a transparent over it? Guess I could do the same thing putting
gold foil over a black opaque first coat.

If I am fabricating using sterling… can I coat the metal parts
with Prips flux or FireScoff when I fire… will fluxes mess up the
enamels. I’d assume they would mess up a transparent if I got it
onto the enamel.

Sorry… lots of questions. The devil is always in the detail isn’t
it.

By the way… I just attended a workshop on enameling that Thompson
offers in Northern KY at their plant. Very affordable and a great
workshop. Info is on the Thompson web site.

Thanks!

2

Enamelling onto sterling silver works fine, take a look at my album

see

all of the transparent blue enamels are on sterling silver. As for
soldering, when making small solder joints that are to be covered by
transparent enamels I solder metals with 18ct white gold solders. I
have had no success of enamelling with transparents over silver
solders, although many opaques will enamel over the high melting
point solders, over here in the UK our bullion dealers sell a high
melting point silver solder called enamelling solder which has a melt
range of between 730C and 800C. this solder is OK for soldering
joints close to enamelling, but not great if enamelled over as some
enamels will not adhere to the solder and will chip off.I find that
the best enamelling is achieved by enamelling onto a freshly cut
clean metal surface so all of my transparent enamelling is done on a
surface that is either cut by engine turning ( guilloche) or I cut
the surface using polished half round Scorpers ( gravers ), these
processes give a bright clean surface texture and you get superb
results when enamelling over these surfaces with transparents, both
on sterling silver and on gold, I never use 999 silver on my
pieces.Peace and good health to all

James Miller FIPG

3

Otto Frei sells an Extra Hard (IT) solder that melts at 1540F. Hope
this helps on the solder issue.

http://www.ganoksin.com/gnkurl/15m

As for using fine silver or sterling, why futz with the copper in
sterling if you don’t have to or don’t need sterling’s harder
nature? The price between the two metals isn’t all that much. Maybe
it is if you’re using gobs of it, but if not.

4 
I understand the issues with solders containing zinc in areas that
will touch enamels. The suggestion one sees is to use the eutectic
solder. So, I look at the "eutectic" solder Thomson Enamels sells
and it flows at 1460 F - that is not the flow point of the
silver/copper eutectic - which is about 1434 F. If I am firing at
1450 F... 1460 F make me nervous, and the true=1434 F flow point of
the eutectic is not going to work.

The thing about enameling is that techniques must be considered in
context of quality to be achieved.

On the low scale, let’s say small bezel filled to imitate gemstone
and you do not care about color and transparency, almost anything
will work.

If you want to achieve bright brilliant colors with high
transparency, and on large spherical shape, ( think about sphere )
than even how many times one exhales while doing it, will make a
difference.

In high quality work, one must abstain for use of any solder,
without exception. Going down, high temperature solders, which you
will have to make it yourself would be required. Take an alloy that
you using and add just a bit of coper to it. That is your solder. If
you using 99 silver, than sterling is your solder.

Silver is best metal for enameling, provides the best adhesion. If
gold is used, the best alloy is 18k green (gold and silver only)

Further deviations would result in lessening quality and even
failure.

Leonid Surpin

1 Like
5

Interesting questions. I’m a bit puzzled though. If I wondered these
things, I would test them to find out for myself. The suspense would
be killing me.

6 
The suggestion one sees is to use the eutectic solder. So, I look
at the "eutectic" solder Thomson Enamels sells and it flows at
1460 F - that is not the flow point of the silver/copper eutectic -
which is about 1434 F. If I am firing at 1450 F... 1460 F make me
nervous, and the true1434 F flow point of the eutectic is not going
to work.

You need to understand how the eutectic solder works. I don’t know
where the folks at Thompson get the melting point number for the
eutectic solder but you are right the silver copper eutectic is
1435F. The thing about soldering with the eutectic on sterling is
you will never get it to remelt at the eutectic temperature once it
flows the first time. The solder diffuses into the sterling or fine
silver and this raises the solder alloys melting point
significantly. You will be safe using eutectic solder with your
enameling but it is tricky to get it to flow the way you expect
silver solder to flow. It takes some getting used to. IT solder has
a higher melting range but does have some zinc in it so transparent
enamels may have some issues.

James Binnion
James Binnion Metal Arts

1 Like
7

Have you tried to fuse your fine silver together and then enamel?
You can eliminate the need for soldering? I once took an enamelling,
fusing and gradulation workshop, and had a few pieces of jewelry all
fused together, gradulated and then enamelled. It was quite
eye-opening at how much you can do with fusing fine silver, and then
get a finished piece afterwards. Once in a while, I’ll fuse a few
things together, so that I don’t have to worry about solder seams.
One thing I did learn, 28g. and 30g. fine silver from Rio does not
fuse well, so it is better to use 26g. fine silver sheet to fuse to
make bezels, and eliminate the hard solder seams. The thicker the
bezel, the better the fused seam. As a result, I avoid 28g. bezel
strip and use 26g. for all of my bezels. Occasionally I’ll use bezel
cups for tiny stones but they are thin.

Joy

8

James:

Thanks for the advice…never thought about using 18K white solder.
And… FANTISTIC goldwork!!

9

Dear James,

Always lovely to look at your work. I have a question when you say
you say: " my transparent enamelling is done on a surface that is
either cut by engine turning ( guilloche) or I cut the surface using
polished half round Scorpers ( gravers )"

When I looked at ‘guilloche’ in google images it showed a pattern,
not a tool. How do you put this pattern onto the metal is that’s what
you mean?

Many thanks,
Sharron

10

Sharron asked about Guilloche enamelling. Well this is a process of
cutting a geometric pattern into the surface of the metal before
covering it with a transparent enamel. A process much used by the
Russian masters in the past. The patterns are cut into the metal
surface using hand operated Engine Turning machines, there are two
main varieties, a Rose Engine that cuts circular patterns and a
Straight Line Engine which as it says cuts straight line patterns.
One of the UK’s last makers of these machines was G. Plant & Sons,
but they stopped making these machines in the mid 1950s and these
machines are now regarded as antiques. See;

http://www.ganoksin.com/gnkurl/16c

Here in the UK we only have a few companies who have these machines
along with their skilled operators. These patterns can be replicated
using modern computer operated routing machines, which are very
expensive to install, but an old engine turning machine does not need
electricity as it is operated by a skilled person turning
handles.Peace and good health to all, and let us hope that the price
of gold stops going up as it is killingthe trade here in the UK.

James Miller FIPG

11 
One of the UK's last makers of these machines was G. Plant & Sons,
but they stopped making these machines in the mid 1950s and these
machines are now regarded as antiques. See;

At least as of a decade ago, there was at least one Swiss company
still manufacturing both rose and straight line machines. At the time
I last saw them, they cost a good deal more for those new machines
than the used Plant machines fetched at auction, when you could find
them (the new ones, a decade ago, were going for something like 75
thousand dollars, if memory serves, which may be an incorrect memory)
Last time I saw a decent Plant straight line machine in an auction,
it went, I think, for under 25K…

And for those interested, U.S. made antique straight line machines
under the brand names of Hall, and Field, are smaller and simpler
(sized for working on things like cigarette lighters and pens, and
jewelry scale items), but also a lot less costly. Mine, originally
made perhaps in the 20s or 30s (just a guess), cost me around 800
dollars in the mid 1990s, though I had to put in a good deal of work
to get it into working condition. I see them from time to time at
Gold Machinery’s web site, already reconditioned, usually for 2 to 5
thousand. Rose engines are more…

Peter Rowe

12

James,

Here in the UK we only have a few companies who have these
machines along with their skilled operators. These patterns can be
replicated using modern computer operated routing machines, which
are very expensive to install, but an old engine turning machine
does not need electricity as it is operated by a skilled person
turning handles.Peace and good health to all, and let us hope that
the price of gold stops going up as it is killingthe trade here in
the UK.

Your wisdom is usually good but here you are wrong on $$

No mater how how I figure it my fanciest CNC with a couple of
computers and much software is about 1/2 the price of a $22.9 K
machine. Electric usage is the least of my concerns, if the power
goes off I am not going to work by candle light. I know all too well
the learning curve on a CNC machine, to become skilled at using an
engine turning machine does tend to scare me, and I don’t scare
easily.

jeffD
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand

13

Jeff, when I wrote my comments about engine turning machines versus
CNC machines I am only talking about my own personal experiences. As
to the costs you quote, they are today’s costs to collectors. I used
to give advice and help to the late Robert Whiteside in Dallas, and
in 2005, I arranged for a friend of mine to sell Robert a pair of
Plant engine turning machines, complete with all of the tooling, I
know that Robert only paid $15,000 for both machines, which were,
Plant straight line and a rotary machines complete with all
accessories, these machines were used in the London workshops of
Cartier so were in great condition and top of the range. Another
goldsmith friend of mine has invested in a couple of top of the
range German, J Schmalz, CNC routing machines for his workshop. They
cost him around $150,000 each about five years ago. I recently had an
antique restoration job where I had to replace a guilloche enamelled
plate to the base of an oval snuff box. The engine turning company
that I now use, is equipped with Plant engine turning machines, they
quoted me ?150, the equivalent of $200 for the engine turning work,
my friend with the CNC machines told me that preparing the program
to cut the patterns on the 4 inch oval panel would cost me ?950 or
in dollars $1500, although the machine would then be able cut the
pattern in a few minutes, these prices are OK if you need to cut
hundreds of the same pattern but for one off jobs, no way.

As for working without electricity, you say that you are not going
to work by candle light, well I was referring to daylight hours.
Back in the past here in the UK we have had union troubles with
power strikes and during these times I worked full days at my bench
working by daylight without the need for electricity.

The attachments show the panel of the box, with the patterns cut by
on engine turning machine, and after enamelling,

507×1155 241 KB

James Miller FIPG

14

If you are considering doing engine turning you might add the modern
Lindow White rose engine to your list. I have one of these as well as
a Kenloc straight line machine and use them for engine turning on
fine silver and subsequent enamelling. The L-W rose engine is
manufactured in Lake Ariel, PA and can readily do patterns similar to
the one shown in James’ attachment. If you are interested you should
contact David Lindow, who is knowledgeable on the subject and also
has a number of antique engine turning machines.

Ramsay Holmes

15

There is a new manufacture of silver guilloche (engine turning) disks in US:

I ordered couple of pieces, they look good.