View Full Version : what i got?? "silver brazing alloy"

11-03-2007, 12:31 AM
so i got a HUGE ASS roll of this stuff. said, like the title says, "brazing alloy, silver" thought it might be silver solder, but i tried to do a muzzle break insert im working on, got it glowing red and wouldnt melt it yet, so im assuming that it is actual brazing stuff and not soldering stuff, or its QUITE possible i was not doing it correctly, ended up lead soldering it, anyway.......

is this for brazing??

same flux i usualy use to braze??

why, specificly, would one prefer silver braze over std brass braze??

special applications???

11-03-2007, 12:54 AM
There are hundreds of brazing alloys, each with a purpose.

Do you have an alloy, part number, mfgr, any info?

If not, you have some pricey scrap metal. Determining the alloy will cost more than it's worth, (if this is a pound). If you have 100#, that's another story.

Bruce Griffing
11-03-2007, 01:57 AM
Silver brazing alloys are generally expensive. To braze (silver solder) with the stuff, you need flux. Borax works pretty well, but there are better commercial fluxes. You will need a hot torch. A simple propane torch in not really hot enough. Mapp can work on small items, but oxy/acetelene is easier. That said, you can overheat.

11-03-2007, 02:50 AM
The silver brazing alloys generally range from 5-75% silver. The melting temperatures are around the 1200-1600 degree range so you're going to need a torch. There should be a number or a trade name on the spool that identifies the alloy.

11-03-2007, 06:47 AM
As has been stated depending on the silver amount and what other alloys are in it the temps does change.

The principle by which the filler metal is drawn through the joint to create this bond is capillary action. In a brazing operation, you apply heat broadly to the base metals. The filler metal is then brought into contact with the heated parts. It is melted instantly by the heat in the base metals and drawn by capillary action completely through the joint.
Is from the web site below a short brazing instruction.
Is a link to 6 basic steps in brazing. this site has a lot of info and the section on fluxes and the alloys of silver brazing used is broken down with everything and anything needed to make a chose. They are one of the largest makers of silver brazing alloys.
And by the way anything over 840'f is considered brazing. Soldering is a low temp join method.So All silver soldering is silver brazing.

Your Old Dog
11-03-2007, 07:46 AM
The silver brazing wire I have requires black flux and it's supposed to be noxious so it's used with good ventilation.

11-03-2007, 08:21 AM
Good discussion.

Thanks PTSideshow for that seriously good link at:
as it is a seriously good read. I've book-marked it for later reference.

11-03-2007, 09:05 AM
sounds like you've some silver solder. not knowing exactly what kind isn't that bad as they're all close and do pretty much the same thing. Exception is, don't use for anything for food as it likely is a cadmium bearing solder

Silver brazing = silver soldering, although personally i tend to call silver brazing silver soldering, saving brazing for the bronze filler alloys. the difference between brazing and soldering based on temp - 800F iirc

theres silver solder, say 30-60% silver and there are silver bearing solders, 4 or 5%. the later are soft solders and melt at around 400F vs 1100-1200 for silver solders. huge strength difference, some silvers solders are around 60k pis while soft are (iirc) around 5-10k. the other advantage of SS it is good to a much higher temp, ie model boilers.

Propane has more than enough temp to silver solder, however on really big stuff it'll be challenging to get the btu's. O/A requires indirect heating to 1) not burn the flux and 2) make sure the joint is heated through out rather than just the surface. easiest set up imo is to make a corner from 3 insulating bricks that reflect the heat so well

There are SS fluxes, get some. maybe its the same stuff and i'm psychosomatic, but the SS fluxes work perfectly

Search here, tons written on it. work has to be clean and well fluxed. place a piece of SS on the joint and warm it up with propane and watch what happens

11-03-2007, 11:25 AM
thank for the help, didnt check the link yet, but ill be doing that now to learn about the fluxes.

a few replies to what was posted, its a pretty thick wire, id estimate it between 1/8" + 3/16". theres about 40-50 lbs of it. no alloy listed, just a 1-1/2 - 2' diam roll w/ three zip ties holding it. the tag listed the "aquisition price" at $1,180something, sell price $23.65. so i dont think i did too bad.

i have done alot of soft soldering and bronze brazing before, so i am framiliar with both processes. i used my mapp gas torch, didnt have much of a problem getting the part to glow, but it just didnt melt the wire, i was thinking, like someone stated, the thickness of the wire required more heat. need to find a way to thin it. i did try to melt it with the torch (just the bare wire) first and it did so without much problem.

ok, off to read that link now :)

Pete H
11-03-2007, 02:16 PM
Mcgyver makes a good point: It probably contains cadmium. That means you need very good ventilation, because if you burn the solder, you'll get cadmium oxide coming off, and if you inhale much of it it can kill you. And if you're not used to silver-brazing, it's likely you'll burn some.

I was handed a half-dozen flat sticks of silver-braze by a refrigeration mechanic some years ago, and I found it a lot harder to use than the kind of silver solder I used on silver jewelry. I can't remember the brand of flux that worked with it, but it came in a little yellow cardboard can... got it at a local welder's supply.

Pete in NJ

Steve Steven
11-03-2007, 05:50 PM
Look closeley at the roll, if there is a series of dots punched in the metal it is a military silver solder. Three dots is for copper to copper, four dots is for steel to steel, and 5 dots is for stainless to stainless. I don't remember the commercial equilivants for the military grade system. If it has other dots, PM me and I can look it up for you.


J Tiers
11-04-2007, 12:18 AM
Not sure about the comment that you got it red hot and it didn't melt..... there's red and there's red.....

Most any silver solder/silver braze can be melted with a propane or butane torch, and good joints made. The most problems people have is too little fire for the size of the part, that's why they always say you need acetylene, its a lot hotter and compensates.

If it is a real "brass brazing" alloy, you can't do it without an acetylene torch.

The only benefit of acetylene for lower melting alloys is the ability to get in on a small spot, heat it, solder, and get away before some other joint melts. You can't do that with a cold flame like propane.

11-04-2007, 12:35 AM
The silver brazing wire I have requires black flux and it's supposed to be noxious so it's used with good ventilation.

Is that right YOD? I've been using the normal blue brazing flux on 55% silver brazing wire. It doesn't wick as well as bronze does, so maybe I need to try the black flux...

so i got a HUGE ASS roll of this stuff. said, like the title says, "brazing alloy, silver" thought it might be silver solder,

Does it have an AWS number on it? You can look up the manufacturer and alloy based on the AWS number.

You can also tell the Silver content by the melting point -- Silver has a melting point of 1700 F, so the higher the melting point, the more Silver.

5% silver brazing wire melts around 800, 45% melts around 1100...

Product.................................ALLOY..... ................MELTING RANGE.....AWS Designation

45% Ag with cad.....45%Ag 15%Cu 16%Zn, 24Cd....1125-1145..........BAg-1
45% Ag..............45%Ag 30%Cu 25%Zn..........1225-1370..........BAg-5
50%Ag with Ni.......50%Ag 20%Cu 28%Zn 2%Ni.....1250-1305F........Bag-24
56% Ag..............56%Ag 22%Cu 17%Zn 5%Sn.....1145-1205F........BAg-7
65% Ag..............65%Ag 20%Cu 15%Zn..........1240-1325 F.......BAg-9
72% Ag..............72%Ag 28%Cu................1435F.............BAg-8
Pure Silver.........99.99% Ag..................1761F.............BVAg-0

Herm Williams
11-04-2007, 01:06 PM
With that amount of wire I would check with a recycling center to find a center to analysis the wire to get the correct composition. In San Diego it costs about twenty dollars to have a metal checked to see what it is made of.

11-04-2007, 10:50 PM
Steve Steven,

Where'd you get the "dot" data?

I just looked at some of mine, and what I know is Sil-Phos has 3 dots, and some smaller that I thought was EZ Flow also has 3 dots.

Rest has no dots.

I'm about to send mine of to a recycler. Last time I wanted to, silver was 6 or 8 bucks an ounce. Handy and Harmon rep said it wouldn't be worthwhile.

At 14 and a quarter Friday, it should be. It's just sitting here being tripped over.

I'll keep what I think I will use in my twilight years, get rid of the rest.



11-05-2007, 08:44 AM
Look closeley at the roll, if there is a series of dots punched in the metal it is a military silver solder. Three dots is for copper to copper, four dots is for steel to steel, and 5 dots is for stainless to stainless. I don't remember the commercial equilivants for the military grade system. If it has other dots, PM me and I can look it up for you.


thought it prob is (military, it came from a govt surpluss store), but cant find any dots. how large and far apart should they be?? i thourly inspected about 1', and glanced over the rest of the coil and saw none.

ill have to look to find somewhere to test it.i can handle paying $20 for it.(the test)

Steve Steven
11-05-2007, 11:10 AM
My "dot" imfo was from my pipe shop days, and refered to the military specification for silver brazing alloys.

I just did some searching, and found that the "dot" system was deleted from use by revision A to QQ-B-564, which is the applicable specification. My source for such data does not have the origional specification, only the revision A.

I havent found an open web site where you can view this specification, but I could email a copy to you. The "dot" system was used with "grade XX" designations, where the numbers 1 thru 8 were in Roman numerals and refered to specific alloys. Hope this helps.


Steve Steven
11-05-2007, 08:16 PM
Here is a link to a Handy&Harmon web page where the "dot" system is given.


The column labeled "Fed Spec. QQQ-B-564A..." has several entries where there is a Roman numeral in parentheses, the roman numeral is impressed on the metal as a series of "dots", or at least it was before 1991 when amendment A of the spec was invoked and the dot system was stopped. This gives the composition of the wire.

The spec does say that both ends of a roll of wire is to be labeled with a tag, yours must have come off.


Mike W
11-05-2007, 11:04 PM
Speaking of silver alloy, I was given a box of 1/8 square by 36 inch long rods. The box has Eaglehard Silvaoy printed on it. There is a place where the info tag had been at one time but is gone now.

There is a hand written MC #56-3324 on the box which may be shipping info. Under a printed list of standard precautions when brazing, cadium free is mentioned if it pertains to this product.

I tried a couple of tests and it seems to melt at a higher temperature than the 45% silver alloy I am used to. One thing I noticed is that the square wire is very stiff. You can file it. I checked for dots but didn't find any. Anyone ever heard of Eaglehard? Thanks.

Steve Steven
11-06-2007, 01:40 AM
Mike, the Engelhard company has changed names and is now known as Wolverine company. Here is a site with some info on "silvaloy" products, as you can see there are many of them.


Here is the page that says about the Engelhard company.


Hope this is of interest.