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Soldering, brazing, fusion, welding?


Hello I am looking for the real signification of these words. I
am writing a lesson about soldering and I realise that the
signification of soldering is different in English than in
French. In English, solder mean joining with solder and brazing
mean without solder. In French (souder) mean without solder and
(braser) mean with solder. Everything is upside down !!! The
funny problem I have is: here in Quebec, jewelers are using
French words but with English significations probably causing by
our proximity. I have to be sure of what I am writing, tell me
what is Soldering, brasing, welding and fusion for English
speaking peoples. Does the steel welders have the same
interpretation? If there is French jewelers from Europe on the
forum, please tell me you version. Thanks and I will try to do
someting coherent with your advices. Vincent Guy Audette In Quebec


Guy Audette: You do have a greater problem than most of us here
in the States since you have to interchange with two languages
and the terms used in both do not have the same meaning. I will
try to set down my understanding of the terms you’ve listed and
hope that it will at least provide you with a jumping off point.
If further clarification is necessary please feel free to E-mail
me direct.

Terminology can indeed get in the way accurate communication
when attempting to explain the various way in which we join
metals together. In general, both silversmiths and jewelers call
the process “SOLDERING”. However,according to Handy and Harmon,
that term is incorrect. If metals are joined using heat at
temperatures above 1100F it is properly called “brazing” Metals
joined below 800
F is termed “soldering”

But the term soldering is in such common usage, that, when we

refer to metal joining in our field,we mean joining at temp.
above 1100*F. The more technical term would be brazing.

Soldering is the joining of metals with the use of a

metal(usually an alloy of the metals we are joining)which we
call solder, and the application of heat. At the temperatures
discussed the grain bounadries of the metals to be joined are
opened up and the filler metal(solder) penetrates those
boundaries without fusion of the base metals.

Fusing is the joining of parts by bringing their contacting

surfaces to a molten state with heat so that they join each
other by penetration of their atoms without the use of an
intermediary metal such as solder. A common example is the
fusion of a bezel when doing granulation.

Welding is a fusion process in which the welding rod (filler

rod) and the two edges of the joint are melted together to
become one. Not a jewelry procedure.

Spelter is an alloy of brass and is used as a solder for

non-precious metals such as steel and brass. (To add to the
confusion) this process is also called brazing, but the
procedure also requires temperatures above that which is used
for so called soft soldering.

Note: When using soft solder, you cannot flush grind the solder

without materially weakening the join, since soft solder, unlike
hard silver solder, does not penetrate the grain structure of the
metals being joined.

I hope I haven't added to the confusion and in some small way

there has been some clarification. J.Z.Dule


To add to your on jewelry terms used in the US.
Fuison welding is done on similar or dissimilar metals and
requires a fusion welding machine (Sparkie II) and fusion
findings. Fusion findings are manufactured for the fusion
welding process and have a small nib drawn on the finding that
causes the fusion process to work. There is no transfer of the
heat to the surface of the jewelry piece. There is no fire scale
or annealing with this process. A Harney


Guy - when American jewelers say soldering, we mean brazing.
Soldering is done using a low temperature filler metal that forms
a surface bond between the items being joined. Brazing uses a
high temperature metal that flows close to the solidus of the
metals being joined. The brazing material (high temp solder)
diffuses into the metals being joined. The resulting bond is
between the grains of the metals as opposed to just the surface.
Someone else will have to explain fusion and welding. To me,
fusion is a melting together with no filler metal and welding is
melting together using filler identical to what is being joined.
When I attach 14k to sterling I heat the sterling just to the
melting point and an alloy is formed at the interface, I presume
that is fusing. When I size a ring I use a piece of the shank
that has been rolled paper thin and put in the joint and melt is
together, I think that would be welding.

Brett Gober
Freedom Design & Contracting


Dear Guy, Greetings from Ottawa,

As I understand it, in soldering, a very thin layer of metal
that is different (different alloy like 14k used as solder for
18k or completely different from the metal being joined like
tin/lead used for copper wiring). In welding, metal of the same
kind as the pieces being joined is used as a bridge from one
piece to the next. Soldering will not normally fill in any gaps
so you must have a very good fit between your pieces, but
welding does fill gaps. Brazing is like welding in that you are
bridging between pieces and can fill gaps between them, but the
metal that you use for joining one piece to another is a
different kind (like connecting two bits of steel with brass).
Finally, in fusing, you are joining one piece to another by
melting them together. This is rather like what a blacksmith
does when two pieces are heated red hot and then hammered
together. It is also what happens in kum-boo when the gold
adheres to the silver or in solderless mokume-gane work. I hope
this helps. MP



In France souder means with solder, braser without solder, same
as in english. En esp=E9rant que cel=E0 vous aidera.

Philippe Durand
Papara, French Polynesia


Guy…You are not alone. Some of us feel upside down in
every language !!

In America, soldering, brazing and welding all use filler , or
additional materials at the joint. Soldering is done at
relatively low temperatures, altho depending on the solder being
used the temperature will vary. You are aware that in silver and
gold soldering we have Hard solders and Soft solders with the
Hard solder requiring a higher melting temperature than the soft.

Brazing is done at higher temperatures than solder and generally
use a brass or bronze filler rod.

Welding is done at higher temperatures than either the solder or
braze. It is done at or very near the material melting
temperature and uses a filler material that is almost identical
in chemical content to the material being welded.

When two pieces of material are joined by melting the mating
edges, and no filler material is used, we say that they have been
fused. By the dictionary definition this is also called welding,
but strictly speaking, fusing uses no filler material while
welding does.

Hope I have helped.

Sol K.