Brazing v.s. silver solder / silver brazing

[mofosheee]

Hello Forum
Alert; novice brazer here. I have previously TIG'ed brazed 1/16 the same mild steel with good success and am hoping to "up my game" I understand that an extremely strong joint can be created via brazing/silver soldering. My goal is to achieve the capillary action of attaching/connecting 1/16" mild steel to mild steel via brazing without deformations in the metal or blobs of rod on the surface (if possible) Note; I have prepped the metals stupid clean and created a 0.001" to 0.005" clearance between them.

Use of MAPP gas seems to be inefficient and much more difficult than TIG brazing. Seriously considering purchasing an ox/acetylene set up (if that helps the cause)

Questions regarding;
1) comparative strength of silver soldering v.s. brazing
2) rehardening hardening and tempering metal to restore it's hardness and toughness properties

It is my understanding that sheets of silver solder are sold in sheets of varing thickness and I have watched videos of techniques where people
have flattened silver solder using a hammer to thin it out. What more can I do? Thank you.

Any and all advice appreciated.

 

[Jake M]

Hello Forum
Alert; novice brazer here. I have previously TIG'ed brazed 1/16 the same mild steel with good success and am hoping to "up my game" I understand that an extremely strong joint can be created via brazing/silver soldering. My goal is to achieve the capillary action of attaching/connecting 1/16" mild steel to mild steel via brazing without deformations in the metal or blobs of rod on the surface (if possible) Note; I have prepped the metals stupid clean and created a 0.001" to 0.005" clearance between them.

Use of MAPP gas seems to be inefficient and much more difficult than TIG brazing. Seriously considering purchasing an ox/acetylene set up (if that helps the cause)

Questions regarding;
1) comparative strength of silver soldering v.s. brazing
2) rehardening hardening and tempering metal to restore it's hardness and toughness properties

It is my understanding that sheets of silver solder are sold in sheets of varing thickness and I have watched videos of techniques where people
have flattened silver solder using a hammer to thin it out. What more can I do? Thank you.

Any and all advice appreciated.

Both silver soldering and braising are gonna easily get you in the 60 plus KSI strength range. (check the product spec's, there's options). How strong the joint comes out is up to you. Either way it'll be pretty on par with the strength of mild steel.

Mild steel won't harden, you can heat it up all you want in that regard.

Deformation shouldn't be tangibly much, especially if you keep it heated kind of evenly. You're not gonna get it "that" hot, and won't be anywhere near welding temperatures, and you'll have a very hard time concentrating the heat with a torch as much as you can with a pointy electrode.

Mapp gas is long gone. Unless you've got old stock, the "Mapp Pro" gas is for all intents and purposes, propane. Technically it's a little hotter, but outside of a laboratory.... Same/Same. With that said, yeah, there is technically "a little extra" in the Mapp Pro, and if you checked my inventory, you'll find that I've probably got one here somewhere... Mostly just to get the bug out of my head, wondering if "just that little bit" would have made a difference, before I drag my (crap) outside and use the little acetylene setup. (Which does not operate indoors in my world. Your space may be different. Mine does not allow for that).

Acetylene torches obviously do very well at heating, but for light stuff like that, you're (probaby, in my experience) going to want to pay very, very careful attention to not concentrating the heat, depending on how much distortion is going to be acceptable. Not knowing exactly what the joint is, the fixturing, the access, etc, for something that small, instead of a welding/brazing tip, I'd "probably" take the smallest rosebud I have, dial in the lowest flame it'll happily hold, and work from a larger distance to heat the whole thing evenly and not chase "hot spots" back and forth. But I don't know what you're working on, so take that only as an option, as if it doesn't make sense.... Well, we're thinking of different joints. And if this stuff is really, really small (probably propane would have been fine....), but there are micro and mini torch sets out there that work quite well. I've never gone there, I can't say first hand, but people that have them seem to really like them.

 

[Nutfarmer]

Be careful when using silver solder. Make sure and use the high silver content. There are silver solders being sold that are only a small percent silver and aren’t any better than standard lead tin solder.

 

[GrifterGuru]

As regards Brazing / Silver soldering, I have had vast success with an OxyTurbo kit (May be called something different in the US) It uses either Propane or MapPro gas (I have both) as fuel + Oxygen.

I do go the extra step of using a Mp Torch to preheat the work, so the OxyTurbo has less material to heat up from cold and saves the expensive Oxy to boot.

What have I braized? Bicycle frames. Custom built bicycle forks and more besides.

I have happily brazed and silver soldered with the kit and have had ZERO complaints other than the expense of the small oxy bottles since I can not keep even a "small" oxy bottle on the property (Yet propane or MapPro is ok for a blowtorch??), having to "buy in" Oxy specifically to do a job.

I have seen this little torch heat steel up to almost yellow hot when "experimenting" with what it could do before putting it to work.

THIS (<< Link) is the kit I have, although it is somewhat augmented (with an additional 3x value of additions than the basic kit itself).


Not sure if this will work for you, but as compact, portable options go, it is a highly useful kit, at least, for me personally.


A sample of some of the work completed using the OxyTurbo kit.. Not even a hint of a problem from any of the brazed joints, despite the sever punishment testing this thing has been put through.





These forks were built specifically for a Never Built, prototype Design Raleigh Chopper known as "Activator", that a friend and I built. He financed the build and owns the bike, I did most of the heavy work, other than modifying the headstock of the frame.

 

[David2011]

Nutfarmer is so right! The hobby “silver soldering” kits that come with a small roll of solder and a little bottle of flux are no better than electronics solder. The flux is great but the solder has a melting point lower than electronics solder.

 

[Ulma Doctor]

Soldering is below 842F
Brazing is above 842F

 

[C-Bag]

I am old school and have never tig brazed. Never even heard of it until a couple of years ago on a This Old Tony YouTube. My basic kit has always been O/A and added mig and plasma from there. I’d not messed with silver solder until recently when i silver soldered a stainless counter top for a kitchen project. Much like all my experience with brazing and soldering #1 is surface prep and the appropriate flux. I’m not a tig guy(tried it a couple of times) but for brazing and soldering especially for capillary effect I love O/A for the fact it’s easy to get up the amount of heat to get going but then spread it to spread the braze or silver solder. But I started with 18ga projects butt welding then went to brazing then recently silver soldering.

 

[ChazzC]

As regards Brazing / Silver soldering, I have had vast success with an OxyTurbo kit (May be called something different in the US) It uses either Propane or MapPro gas (I have both) as fuel + Oxygen.

I have seen this little torch heat steel up to almost yellow hot when "experimenting" with what it could do before putting it to work.

THIS (<< Link) is the kit I have, although it is somewhat augmented (with an additional 3x value of additions than the basic kit itself).

Not unlike the Bernz-O-Matic Oxy/MAPp set.

I have a Smith Little Torch outfit that will run on MAPp or Acetylene:


The nifty carrier may no longer be available.

For larger jobs I have a rosebud tip, or use my ORCA Torch (didn't pay that for mine a few decades ago). Get more heat (not temperature) from the larger tips than you can from regular propane/MAPp torches.

 

[mofosheee]

Very informative and great responses.............everyone of them!
I don't braze often and when I do it's been by tig with silicon bronze, resulting in unacceptable deformations of a precision device.
With the above advice, I'm going to invest in some version of a non Chinese jewelry grade kit and practice practice practice.

Thanks to all!

 

[C-Bag]

My home O/A is what we call burglar tanks, the smallest set you can get. Yeah, you don’t want to do any cutting with it as it eats up the little ox tank in a hurry but that’s what the plasma is for . But for just welding/brazing it last me forever. And takes up little space. I also like the smaller torch than like a journeyman setup. I’ve had my setup for 40yrs and finally had to rebuild the ox regulator. But good as new after that. The only hiccup is it can be hard to find tanks at your local weld shop so I went up the next size tanks.