I want to make a flat piece of brass with a ring soldered to it so it
can fit onto a keyring. I am lousy at soldering. Can anyone tell me exactly
what kind of solder to use, flux, and what to look out for? I'm looking for
a clean joint that isn't obtrusive looking, so bright silver solder is out.
I have considered machining a ring integral with the part but that means
the ring would be brass like the flat piece and it seems to me that brass
wouldn't hold up too well on a keyring. The flat piece will be approximately
1.75" roundish, not too heavy, and about 0.100" thick, old propeller shafting
from a sailboat. Might be phosphor bronze or manganese bronze and not brass,
I'm not sure.
"Grant Erwin" wrote: (clip) I'm looking for a
clean joint that isn't obtrusive looking, so bright silver solder is out.
Jewelers use solders which match various shades of gold. Since you say you
are "lousy" at soldering, you could probably get it done for you by a
jeweler, maybe for less than the cost of a length of the appropriate solder.
The ability to make a solder joint that does not "stick out" depends not
only on a color match, but on a minimum amount of solder, cleanly flowed
into the joint, and nowhere else. This requires the right technique and
Since this is RCM, I will answer the question that you didn't ask. That
is "How can I fasten a flat piece of brass to a key ring?". The answer
is drill a hole in it for the key ring to pass through. Bob
Since your piece of brass is about .1 thick, I suggest drilling two
small holes in the edge. Make a loop from some wire of your choice
and stick the ends in the two holes. Solder with any kind of soft
solder. File off the excess solder and you will barely notice the
silver colored solder.
The solders used by jewelers for soldering gold are mostly gold. E.g.,
14karat or 10karat. You use yellow gold solder for yellow gold, white gold
solder for white gold, pink gold solder for pink gold, etc. These solders
will not work for brass because the melting temperature is too high. Also,
they are torch soldered, which is dicey for brass.
A thin ring, soldered edge on to a relatively thin disk is a stress point,
no matter what solder you use -- and it will not hold up well on a keyring.
As someone else suggested in another reply, better off trying to improve the
mechanical joint and strength. I would drill two small holes into the edge
of the piece -- e.g., 0.02, to match the wire you ar using for the loop.
As always, very clean is mandatory. You can use low temperature
silver solder with a torch or high temperature tin-based solder with a
soldering iron. I prefer silver solder with a torch. If the match of the
wire to the hole is good, and the area very clean, then you will use very
little solder -- e.g., a piece about 1mm on a side should do for each joint.
The silver solder has a yellowish tinge and once soldered, the joint is
almost invisible. A little cleanup with emery or a rubber abrasive wheel
will make it invisible. Use a very fine torch tip -- really fine -- and
remember that you don't heat the solder, but the place to which you want the
solder to flow.
I do it all the time with the fittings I make for my ship models.
You can't see the joint if you do it right.
I prefer silver solder with a torch. If the match of the
What Boris said. *Exactly* what Boris said. Silver solder, "real" silver
solder, is almost identical in appearance to yellow brass. A properly
fitted joint that has been soldered in keeping with good practice would be
strong, and have a nice corner radius if you use the appropriate amount of
solder. That's the nature of silver solder. The only concern will be that
heating the brass hot enough to solder it will anneal it.
Do not confuse solders with 5% or so silver content with silver solder.
The only thing they have in common is the fact that silver is mentioned in
the names of each one.
Grant, if you need a small amount of silver solder, send my your address on
the side and I'll put a little in the mail to you. You'll need some flux
for silver solder, which is available at welding supply stores.
Really? The silver solder I've used for sterling silver is, well, silver
colored. It's available in soft, medium and hard from the precious metal
dealer. The 'hardness' refers to the melting point and thus the silver
content. The color match is nearly perfect when soldering sterling with hard
I believe that one would need to make an old fashioned brass spelter to get
a decent color match. That's obviously unnecessary as previous posters said
a tight fitting joint and very little solder will make excellent joints.
Silver solder is not intended to fill large gaps anyway...
I believe that's called 'silver bearing solder'. It can be really important
not to get solders with lead and real silver solder not mixed up. Another
tragic case of language not being useful enough for technical purposes -
isn't silver soldering actually brazing because of some special property of
silver?. Anyway, if you heat a silver piece thats got lead solder on it up
to silver soldering temp, the lead will burn pits in the silver.
You got me there! What you use is, in a sense, silver solder. What it
really is is solder for silver.
OK, lets talk about this in a slightly different light. In industry,
there is a solder that is called "silver solder". It is a solder
comprised of silver and copper, generally with some sacrificial element,
often cadmium. It has a color similar to brass. The alloy varies, but
it runs in the area of 50% silver. It is not solder for silver. There's
a huge difference. Most people associated with the machine industry
understand what silver solder is.
Right. Silver solder is not a filler material, and is most effective when
there is a proper fitting of the components.
There is no need to make any kind of spelter, silver solder will perform
exactly as indicated. Silver solder. Not solder for silver.
I'm not sure exactly what constitutes brazing as opposed to soldering, for
in each case the base metal is not melted, but the soldering medium is. I
get the idea that the main difference is that in brazing one can effectively
build up an area with the brazing material, whereas in soldering it is to
be discouraged, and works poorly when attempted. Where's Ernie when we
The qualities of lead you described are exactly why one should never uses
lead with precious metals. The solvent qualities are apparent even al low
temperatures. Platinum, for example, melts at over 3,000 degrees F, but
dissolves in molten lead. It is lead's solvent quality that makes it so
useful when assaying. It is introduced to the heat in the way of
litharge, along with the appropriate fluxes for the assay in question.
The lead that is reduced from the litharge dissolves traces of precious
metals and concentrates them in the lead so they can be recovered. The
lead is once again reduced to litharge in the cupelling process, leaving
behind a button comprised of the values.
The terms 'silver soldering,' 'silver brazing,' and 'brazing'
are often used interchangeably in industry. "Braze welding"
or brass welding is quite different as a rule.'
Yep. The silver solders with cad in them will flow like crazy into
the tinyest crack or joint. There is really no need to leave a
gap for the filler the way that soft solder requires. My favorite
story was related to me by Arthur (Bud) Embry who was the 'torch
brazer' at work when I hired on there. I learned to silver solder
by watching this man. He said that during WW2 the liners were
pressed into anti-aircraft barrels and then a gang of men with
rosebuds would heat up the entire barrel to the flow temperature,
and then the silver solder would be applied to one end of the
barrel liner - and it would wick all the way down the five or
so feet and appear as a bright ring at the other end.
Again, the term "braze welding" is typically used when one is building
up a joint like that - when the entire item is not brought up to the
flow temperature. But when the entire joint is brought to the
flow temperature this is brazing. The heat can be applied via
torch, or sometimes by placing the entire item in a furnace with
a controlled (typically reducing) atmosphere. In the latter case
one can use things one does not typically think of as a braze material,
for example, gold, copper, nichrome. These can be applied in advance
to the joint as a preform (ring or sheet) or can be applied as
a paste of binder and metalic powder. Extremely intricate work
can be done this way. Bud was in charge of the hydrogen furnaces
and after he died things kind of were never the same. A real
No doubt somebody will chime in here and claim I am full of it, (probably
am) but I think that if it melts above about 900F then that is brazing
and below that it is soft soldering. Purely an arbitrary line drawn
in the (temperature) sand because the process is *exactly* the same:
joining two similar or dis-similar materials, using a third material
as a kind of inter-atomic 'glue.' The adhesion forces that make
solder of any kind stick to another material's surface are not really
well understood by physicists in general. There is considerable
discussion even now about the physical processes of "adhesion" in
some industries. Like mine.
I found out how well lead can dissolve gold the hard way - by trying
to solder a 0.003 inch diameter gold wire with lead-tin solder.
Talk about frustration!
But to re-cap: The following terms really mean the same thing:
When one lumps up brass on a cold item, that is
best called brass welding or braze welding.
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
About the time I left Sperry, they had started building a new product that
escapes me now. At any rate, it was furnace soldered. The most beautiful
of work. Perfect joints in every case. The item was made up of several
individual pieces, and I recall that the solder was pretty much copper
I imagine you've played with gold plated electrical pins in the course of
your hobby or work. Have you ever noticed that they are plated with nickel
before gold is applied? Sir T.K. Rose, in his Metallurgy of Gold,
documents the phenomenon whereby gold and silver, placed in intimate contact
with one another, will migrate from one to the other. Pins without the
nickel barrier slowly absorb the gold plating, leaving behind nothing more
than a copper or brass pin that has a miniscule amount of gold in its
makeup. Not enough to prevent corrosion. That happens at room temps.
No wonder heated lead is so aggressive.
You're full of it, Jim. :-p
Really, it's spot on.
They say the temperature of brazing opens the crystal structure a little,
enough for a small amount of braze to wick in. It's certainly far, far
stronger than soldering with tin, lead or zinc. I haven't had silver solder
work right with steel so I'll lump it in with soft solder too. ;-P
I have however silver soldered brass and copper with the same strength (that
is, stronger than the base metal due to the added stiffness). But you can
also solder lead together with tin-based solder and it might as well be
welded. (No doubt as the metals are extremely compatible and likely the
solder dissolves into the lead, but that's beside the point...) As such I'd
like to say lead can be brazed, and this would bring about a new definition
of brazing where the base metal is strongly bonded to the filler,
temperature-wise it's probably a fraction of the melting point, with respect
to absolute zero no doubt. And also probably related to the expansion rate
of the metal.
I'm sure there is. Certainly a lot of quantum physics has the chance to
But hey, it makes gold-plated connectors easy as fudge to tin! :)
Tim (posting tired so don't be too hard on me ;)
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
This is nonsense. I'm a jeweler with over 40 years experience and, in order
to match colour, have used gold solder on brass from time to time with no
By the way, Johnson Matthey make a brazing alloy called MATTIBRAZE 34 which
has a yellow colour. I've used it on brass and the joint was just about
invisible. The melting range is 602-668 C (1117-1234 F).
Regards, Gary Wooding
(Change feet to foot to reply)
The nickel in this case is called a 'diffusion barrier.' Other
transition metals, notably titanium, can be used that way. This
is common in integrated circuit wiring.
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
Well, We broke a couple distributor drive gears on our old Renault R12
rally car years ago, and didn't have another one available when we
finally figured out what was breaking them, so I silver soldered one
back together. We rallied it for 3 years, and my brother used it for a
beater for 3 more. The soldered gear was still in one piece when the
body finally fell off and he scrapped it.
It was a (cast) steel gear.