Silver soldering.........

bulgie said:
Using silver filler rod is still brazing, not soldering, if you use silver brazing filler. I use 40% silver if the gaps are a bit bigger and 56% for tighter fitups.
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Thank you for that!
 
pontiac428 said:
Yes. Brass is not as easy as hard solder in terms of wicking, so heat control matters more. Heat past the joint on the sleeve side, leaving the joint slightly cooler, and the braze will draw itself in.
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I've had good success with TIG brazing but I don't like the look or the amount of heat applied and the resulting distortion of parts.

Experimented with both 56% silver solder then ox/acetelyne with brazing rod. 56% SS "flows" much better/easier and looks great.
Although a snug fit exists, (slip joint pipe) I'm unsure about the existing joint clearance and am hoping/looking for that desired 0.002 to 0.005 fitment for strength of the joint............ which is pushing me towards brazing (if I ever get the hang of it)

The wicking of rod with ox/acetylene worked (although not pretty) due to my poor technique and inexperience.
 
mofosheee said:
I've had good success with TIG brazing but I don't like the look or the amount of heat applied and the resulting distortion of parts.

Experimented with both 56% silver solder then ox/acetelyne with brazing rod. 56% SS "flows" much better/easier and looks great.
Although a snug fit exists, (slip joint pipe) I'm unsure about the existing joint clearance and am hoping/looking for that desired 0.002 to 0.005 fitment for strength of the joint............ which is pushing me towards brazing (if I ever get the hang of it)

The wicking of rod with ox/acetylene worked (although not pretty) due to my poor technique and inexperience.
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The flow temp isn't necessarily proportional to strength. Hard silver solder is strong as heck and flows like a wet dream, but it costs a lot and you might have to launder your pants afterwards. Braze is accessible, cheap, and strong, but the cleanup isn't always a fun time because of the excess required to fill and fuse wicked joints. Pb-Ag hard solder overburden tends to roll off or bead tight to the joint due to the flow properties that make it such a good wicking filler, making it an easy cleanup. That's especially worth considering if the job involves riffler files to cut back residual filler. Silicon bronze is a wonder material and has the added benefit of cladding but you gotta get comfortable with it before trying any fine work. I'm okay with people calling silver "brazing", but it is technically hard soldering. The difference between soft solder, hard solder, and braze is the flow temp. Silicon bronze is a high temp braze, but still a braze. It doesn't become a weld until the base metal melts and fuses with the filler. Anyway, glad you got some practice in.

I attached some stuff below from my library for those who are curious.
 

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pontiac428 said:
I'm okay with people calling silver "brazing", but it is technically hard soldering.
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I'm OK with people calling silver brazing "hard soldering", but in most industries it's called silver brazing. That's also the definition used by the American Welding Society as well as Lucas-Milhaupt, Harris etc. It is definitely brazing, by any definition I have ever heard. I prefer not to call it "hard soldering" because that's a different category of fillers in my book, lower temperature than brazing. But I concede that the terms are widely used as interchangeable. We'll allow either, with the one thing that's absolutely wrong is saying it's not brazing.

Over 40 years of brazing experience, over 20 years doing it as a main part of my day job, quite a bit of it with silver. Never did any silver soldering though, it was all brazing.
 
bulgie said:
(2) silver can wet out on stainless, which brass does only reluctantly. Brass braze on SS is likely to make a weak bond if it flows at all.

One cool option with silver is powdered filler mixed with paste flux, that you can paint on the parts before assembly. Then just heat until all the silver melts and flows.
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Very timely, thank you. Opened a hole in a SS sprayer for a <40 psi brass bulkhead fitting just a tad too big. I was wondering if silver solder would be viable. Glad I checked out the thread!
Thanks!
 
Shiseiji said:
Very timely, thank you. Opened a hole in a SS sprayer for a <40 psi brass bulkhead fitting just a tad too big. I was wondering if silver solder would be viable. Glad I checked out the thread!
Thanks!
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If your fit-up is too loose for silver braze, you might try nickel-silver. FYI there is zero silver in nickel-silver, it's pretty much regular brass (Cu-Zn), that lots of people call bronze, only with a substantial amount of nickel added. Unlike silver, which melts at a lower temp than brass, nickel-silver's liquidus is a bit higher than brass. Not much higher though; you can use the same flux as for brass. (Some use flux-coated rod but I prefer paste flux.)

Nickel-silver does stick to SS, but it doesn't flow well, not good for tight fits. It builds up a fillet easily, nice when that's what you want, and it's extremely strong, stronger than a lot of steels. So it's great for repairs, e.g. build it up on a spur gear with a broken tooth and remachine the tooth (or hand-file it!), and the gear is as good as new. Some people use brass for that but nickel-silver is da bomb.
 
bulgie said:
If your fit-up is too loose for silver braze, you might try nickel-silver. FYI there is zero silver in nickel-silver, it's pretty much regular brass (Cu-Zn), that lots of people call bronze, only with a substantial amount of nickel added. Unlike silver, which melts at a lower temp than brass, nickel-silver's liquidus is a bit higher than brass. Not much higher though; you can use the same flux as for brass. (Some use flux-coated rod but I prefer paste flux.)

Nickel-silver does stick to SS, but it doesn't flow well, not good for tight fits. It builds up a fillet easily, nice when that's what you want, and it's extremely strong, stronger than a lot of steels. So it's great for repairs, e.g. build it up on a spur gear with a broken tooth and remachine the tooth (or hand-file it!), and the gear is as good as new. Some people use brass for that but nickel-silver is da bomb.
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Thank you! @66 I need others to share as much as they are willing. Too easy to spend most of a day just figuring out what I don't know. And that's just the start.
 
What flux should be used with this. Harris brand 5515. Have a 2 pound roll.
 

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