Will someone please explain to the novices in the forum, what the
difference between brazing, soldering and welding are? What type
of materials *are* soldered?
Brazing is the term used by every one but jewelers for what jewelers
call soldering.
Brazing is defined as joining with a filler metal that is different
in composition and melting point to the metals being joined. In
brazing the filler metal melts at greater than 840 F
Soldering (except for jewelers) is the same as brazing but the
melting point of the filler metal is below 840 F
Welding is joining by melting the materials and fusing them together
at the joint with or without additional filler metal being added
Mostly metals are soldered or brazed but ceramics and glasses can
also be soldered or brazed to metals with special techniques.
what the difference between brazing, soldering and welding are?
What type of materials *are* soldered?
Lora, no doubt you’ll get more than you asked for on this question…
In lay terms that are probably not technically precise. In a word,
practically speaking: soldering is low temperature - under 400C or
750F, brazing is above that and may or may not involve dissimilar
metals, welding is the fusion of the base metal with or without
adding more metal. The important thing is what happens in the
process. Soldering is such a low temperature that the solder doesn’t
bond to the base metal on a molecular level. (If you use soft solder
on pewter, you are using solder to weld or braze…) Brazing is hot
enough that some of the brazing metal interweaves on an atomic level
with the base metal, and in welding it’s all melted together. Think
of it as paper: Put rubber cement on paper, and after it dries you
can roll it up with your fingers - that’s solder. Put Elmer’s glue or
epoxy, and it will permeate the paper - brazing. Make paper pulp and
pour it between two sheets, making one large sheet is welding
(conceptually, anyway).
Yes, technically silver, gold and platinum soldering is brazing. I’m
afraid we’re all going to call it soldering till the end of
time…
The important thing is what happens in the process. Soldering is
such a low temperature that the solder doesn't bond to the base
metal on a molecular level. (If you use soft solder on pewter, you
are using solder to weld or braze...) Brazing is hot enough that
some of the brazing metal interweaves on an atomic level with the
base metal, and in welding it's all melted together.
It used to be the thought that the soft or low temp solder joints
were mechanical not metallurgical bonds. However even with low
temperature solders there is some dissolving of the base metal by
the solder so there is a metallurgical bond even with soft solders.
The only real significant difference is the melting point of the
solder or brazing alloy.
Brazing is the term used by every one but jewelers for what
jewelers call soldering.
So, just keep it in mind when you are talking to a craftsman or
technician who is not a jeweler that they use the terms differently.
No need for change when talking amongst ourselves. Trades have their
jargons and always will.
When I was in high school we were taught that brazing was also
called “hard soldering” and all the tin/lead low melting solders were
“soft solders”. This makes things a bit dodgey when the grades of
silver or gold solders are called soft, medium and hard. (please take
note, United Precious Metals) It ought to be “easy” medium and hard,
so that there is no confusion between a lower melting 65% silver
solder and the silver bearing plumber’s solder that is mostly tin,
which is truly a “soft solder”
The way I explain it when teaching newbies is not only higher and
lower temperatures being what distinguishes soft soldering from hard
solder/brazing is that soft solders require a different flux, usually
zinc chloride, while hard solders generally use borax based fluxes.
The fluxes are NOT interchangeable as some of my students have
learned the hard way.
The way I explain it when teaching newbies is not only higher and
lower temperatures being what distinguishes soft soldering from
hard solder/brazing is that soft solders require a different flux,
usually zinc chloride, while hard solders generally use borax based
fluxes. The fluxes are NOT interchangeable as some of my students
have learned the hard way.
Yes, and I think of fluxes as being necessarily linked to a temperature range, not so necessarily linked to the materials
used.
Brian
Brian Adam
Auckland NEW ZEALAND
www.adam.co.nz
So if someone happens to join jewelry pieces together using Tix
and similar low temp solders (I don’t, it’s just an example) they’re
soldering and if they use jewelers solder they’re brazing. And if
they fuse using no version of solder at all are they really welding?
Great explanation. I guess I could have looked it up in Wikipedia,
but I appreciate all the knowledge here so much.
When customers call small single cut or full cut diamonds {chips}.
Anyone else get this?
I get this routinely. I’m not really sure of the derivation of the
word but I always allowed them to use it without challenge for small
single cuts. On the other hand, when selling my small full cut
diamond melee I always carefully explained that they were full cut
diamonds and were absolutely not “chips”.
Daniel R. Spirer, G.G.
Daniel R. Spirer Jewelers, LLC
I get this routinely. I'm not really sure of the derivation of the
word but I always allowed them to use it without challenge for
small single cuts.
“Chips” derive, I would think, from the fact that in some cases,
that’s exactly what the stones are. Little bits of diamond, Oven
little cleaved “slices”, or bits cleaved in half so as to have a
shiney cleavage plane, but often otherwise natural. I’ve seen some
that were simply tiny triangular crystals, in their natural form.
Tiny Macles… One step below tiny rose cuts. You see them in the
really cheap things, like inexpensive watch bracelets that still want
to be called diamond jewelry. Also one sees such use in some antique
pieces, where sometimes the dividing line between actual rose cuts
and “chips” gets blurred as the workmanship and degree of cutting
goes down… These things seem to have become less common after world
war 2, when most such jewelry items got at least single cuts. Though
I’ve seen modern things, Kmart quality, where the little “chips” in
the old pieces looked better than the “drill bit quality” single cuts
being used now…
I always thought diamond “Chips” were the shrapnel left over from
cleaving. (Much as I thought about it at all, which isn’t much.) What
are they really?
join jewelry pieces together using Tix and similar low temp solders
(I don't, it's just an example) they're soldering
Lora, in this, as in all things, there are definitions and there is
practice. Your above statement is correct on the face of it. And the
definitions of the terms have been posted here already. My analogy
of glue on paper is pretty practical, though - I’d already thought
about expanding this before Lora’s post…
If you solder pewter, which nowadays is pure tin, with tin solder,
then technically you are soldering, because it’s low temperature. In
reality you are welding it (or perhaps brazing), because the
temperatures of the metals are the same, and you are working the
metal in the manner of welding. It’s still called soldering…
If you “braze” platinum with gold “solder”, then you are technically
brazing. In reality you are soldering, because the platinum can’t
get hot enough to make the bond with the gold that is the essential
part of brazing - some atomic bonding under heat. So, when you
stress the joint it will pop, because it’s just glued together. It’s
still called brazing…
Meaning that the definitions mean a whole lot less than the
processes. “I need a joint on this pewter that will hold, so I’ll do
XYZ” We need strong platinum joint, but it’s joining to gold so
we’ll need to add a mechanical assist to assure the strength -
solder alone won’t do it. Stuff like that - understanding is more
than just knowing the rules…
It used to be the thought that the soft or low temp solder joints
were mechanical not metallurgical bonds
I don’t know how long ago that was, but I remember attending a
“solder engineering”* seminar in NYC about 1965, and it was clearly
understood at that time that soft solder (tin-lead) actually alloyed
with copper, producing a joint stronger than the solder. That’s the
reason the joint has to be tight for strength.
*There’s more to the science of soldering than you might think
"Chips" derive, I would think, from the fact that in some cases,
that's exactly what the stones are. Little bits of diamond, Oven
little cleaved "slices", or bits cleaved in half so as to have a
shiney cleavage plane, but often otherwise natural. I've seen some
that were simply tiny triangular crystals, in their natural form.
Tiny Macles... One step below tiny rose cuts. You see them in the
really cheap things, like inexpensive watch bracelets that still
want to be called diamond jewelry. Also one sees such use in some
antique pieces, where sometimes the dividing line between actual
rose cuts and "chips" gets blurred as the workmanship and degree of
cutting goes down... These things seem to have become less common
after world war 2, when most such jewelry items got at least single
cuts. Though I've seen modern things, Kmart quality, where the
little "chips" in the old pieces looked better than the "drill bit
quality" single cuts being used now..
Yep- I have bits and pieces of an old citrine bracelet dating from
the 40s or earlier, possibly made in Italy before WWII, in which the
small stones are all diamond cleavages so that there is a degree of
surface flash without actually polishing anything. The metal appears
to be silver and maybe vermeil for color. (I haven’t bothered with
testing it.) My uncle Tommy brought it back for my aunt when he
returned stateside after VE day. My aunt gave it to me some 30 years
ago.
If you "braze" platinum with gold "solder", then you are
technically brazing. In reality you are soldering, because the
platinum can't get hot enough to make the bond with the gold that
is the essential part of brazing - some atomic bonding under heat.
So, when you stress the joint it will pop, because it's just glued
together. It's still called brazing...
This is a misconception. If you have a molten metal in contact with
a solid one and the solid one is soluble in the molten one then there
will be a metallurgical bond between them as the molten one
dissolves the solid. You do not need to get anywhere near the melting
point of the platinum to dissolve it in gold. Platinum is soluble in
gold, silver and copper and so when brazing platinum with gold solder
you get a diffusion of gold, silver and copper into the platinum
matrix. If you were to take a small bead of platinum and place it in
a crucible of molten gold the platinum would totally dissolve into
the gold given enough time. You do not have to melt the highest
melting point metal first to make an alloy it is just much much
faster to do so.
It used to be the thought that the soft or low temp solder joints
were mechanical not metallurgical bonds
I don't know how long ago that was, but I remember attending a
"solder engineering"* seminar in NYC about 1965, and it was clearly
understood at that time that soft solder (tin-lead) actually
alloyed with copper, producing a joint stronger than the solder.
That's the reason the joint has to be tight for strength.
I am certain that metallurgists realized as soon as they started
looking into it that there was a solubility of the copper but in the
AWS Brazing Handbook there is a reference to the “old” idea of a
mechanical bond in soldering. But I don’t know how old that idea is.
*There's more to the science of soldering than you might think :-)
Quite likely, but I did spend about 15 years in the electronics
field as a tech at first then eventually as a research engineer. So I
am somewhat familiar with soldering practice and basic theory but
soldering was not the focus of my work in electronics. Even in my
early training in the Navy tech schools there was reference to
solder being a metallurgical bond not a mechanical one but there was
some reference to the idea that it “used to be considered a
mechanical bond”
When customers call small single cut or full cut diamonds {chips}.
Anyone else get this?
OMG! I don’t even work with diamonds, but I’ve heard that many
times, and never without cringing! Where do people get these notions?
Do they think those little stones are what’s left over after that guy
finishes cutting a diamond with a hammer and chisel in the back of a
luxury sedan?
One of my favorites, from customers and newbie jewelers, is “pure
sterling silver,” often followed by customers with “so it won’t
tarnish.”
If you "braze" platinum with gold "solder", then you are
technically brazing. In reality you are soldering, because the
platinum can't get hot enough to make the bond with the gold that
is the essential part of brazing - some atomic bonding under heat.
So, when you stress the joint it will pop, because it's just glued
together. It's still called brazing... This is a misconception. If
you have a molten metal in contact with a solid one and the solid
one is soluble in the molten one then there will be a metallurgical
bond between them as the molten one dissolves the solid.
Jim is, of course, correct here, in that there is indeed some degree
of souability and bonding occuring, despite the big difference in
melting points. However, there is also a middle ground in the
interpretation, since that difference in melting point, as well as
composition of the metals being joined, means that the depth of
penetration of that diffusion and bonding is limited. The result is
a much sharper boundary between metal types, and a resulting loss of
strength of the bond compared to a similar joint, with the same
solder, between metals closer in composition and melting points. For
example, if you join a platinum wire prong to an 18K yellow gold
ring using a “soft” white gold solder, you may well find that it is
possible to take a pair of pliers, and literally peel the prong away
again like the old “roll up” sardine cans. Examination of that wire
and it’s former seat looks like the wire just peels away from the
solder, as the solder retains a nice clear impression of the shape of
the wire. The wire, even if polished before soldering, will show
surface “texture” where the solder etched or dissolved a little of
it to form a metalurgical bond. But the shallow depth of that bond
limits it’s strength. Do the same type of joint with the highest
melting solder you can use and still not melt the gold, and heat it
longer, and you’ll find the bond strength much improved, as the
diffusion of the solder into the platinum and the platinum into the
solder increases.
So to a degree, both levels of statement have some truth. The
accurate statement of a true metallurgical bond existing is correct,
but doesn’t completely address the bond strength, which can still
vary based on the dissimilar types of metal. But the statements
claiming merely a “glue” type level of bond, while not exactly
correct, ARE correct in terms of the behavior the bonds appear to
exhibit in real life.
I don't know how long ago that was, but I remember attending a
"solder engineering"* seminar in NYC about 1965, and it was
clearly understood at that time that soft solder (tin-lead)
actually alloyed with copper, producing a joint stronger than the
solder. That's the reason the joint has to be tight for strength.
I am currently doing a lot of electronics soldering these days for
the kind of engineer who really likes to explain stuff… soft solder
does “reach into the world of intermetalics” to quote them… but even
if it the joint is stronger then solder alone, it doesn’t mean much
as that is damnation through faint praise, tin-lead solder has nearly
no strength to it at all.
