soldering to brass

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
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clean joint that isn't obtrusive looking, so bright silver solder is out. (clip) ^^^^^^^^^^^^ 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 torch.
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you
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.
Boris
--

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Boris Beizer Ph.D. Seminars and Consulting
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gold
solders
Also,
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 problems. 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)
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Grant Erwin writes:

Brass keys seem to do fine.
Can't just put a hole in your piece? Maybe with a loose link?
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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
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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.
chuck
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exactly
for
out.
approximately
shafting
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.
Boris
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Boris Beizer Ph.D. Seminars and Consulting
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snip-------
I prefer silver solder with a torch. If the match of the

joint.
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.
Harold
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silver
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 solder.
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.
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hard
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.

get
said
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.

in
important
of
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 need him? <g>
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.
Harold
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(snip)
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.'
(snip)

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 craftsman.
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:
Brazing Torch brazing Silver soldering Silver brazing
When one lumps up brass on a cold item, that is best called brass welding or braze welding.
Jim
================================================= please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com =================================================
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snip--

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 colored.
snip--

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.
Harold
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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.
Jim
================================================= please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com =================================================
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Harold & Susan Vordos says...

nickel
contact
more
Cool! Now it has a name. What a difference an education makes, eh, Jim? To me, it was magic "Gee whiz" stuff. Does an explanation exist on why it works?
Harold
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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 apply...

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 and Games: http://webpages.charter.net/dawill/tmoranwms
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On Wed, 28 Apr 2004 01:49:15 -0500, "Tim Williams"

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.

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