Best braze/solder

[mgbruch]

I had some of what I called "silver braze" that I used MAPP gas on.  Came in a skinny rod (about 1/16"), and was a little pricey.  I used it because it was reported to have a stronger bond than silver solder.  It's gone now, and unfortunately, I can't remember what it was I bought.

Using MAPP or propane, what will give me the strongest bond between two pieces of mild steel?

Thanks

[Daryl]

High Temp silver "solder". There are different grades in high temp silver solder.
The grades used to "solder" the teeth on lumber gang saws is likely the strongest.

We're talking about over 1,000F, not the low temp stuff that is barely better then 50/50 lead tin mixes.

[mgbruch]

What brand names and descriptions do I look for? And the best flux to use with them as well.  Thanks again.

[Scota4570]

Silver bearing solder is now used for plumbing.  It is also called sta-brite.  It is 95% tin with a little silver added.  It works the same as old lead tin solder. It is a little harder to tin with though.  It operates in the same temperatures as lead-tin solder. 

Silver solder is a high temp braze type of material.  The best was the old kind that contained cadmium.  It came as thin sheet or ribbon. IT flowed like water into a joint.  It was great stuff.  Unfortunately  the do-gooders hate cadmium so it was remove from the market. 

[P.W.Berkuta]

Your title of your message is a bit misleading -- "braze/solder" they are two different methods for two different applications. Have a look at this web site and read the explanations for what you may be looking for:
<https://www.brazing.com/products/Brazing_alloys/silver_reference_chart.aspx>
Most all of these silver brazes are high temperature stuff - 1100 degree +. Look at the cadmium free stuff for ferrous and non-ferrous metals that may be what you want to use to protect your health also. All these items are not cheap - good luck.
NOTE: If you are not in the need for a super high strength joint you might get away with a low temp silver bearing solder (Stay-Brite and its flux Stay-Clean) not a silver braze.

[davec2]

Here is an outfit that makes many different alloys. 

https://www.brazing.com/products/Brazing_alloys/silver_reference_chart.aspx

I use a whole range of silver and gold brazing alloys.  Not sure what you are trying to braze, or how strong you really need the joint, but a good rule of thumb is the higher the melting temperature the stronger the joint.....all the way up to welding (i.e. at the melting temperature of the parent steel  ~ 2800F). If used properly, any of these high temp alloys will make a strong, great looking joint.  I have used the alloys available from most weld shops, along with their fluxes, and had good success.  If the joint is very large, I would use the rod type braze material you described.  For smaller parts, the wire version is easier to use.  A simple flux of borax and water will work for most braze applications although there are inexpensive commercial products that have a few more chemicals in them that will help prevent oxidation of the metal surfaces while you are trying to braze the joint.

If you can describe what you are trying to do, I can be more specifically helpful.

Best,

David

[sbowman]

What you may be looking for is jewelers silver solder. comes in wire or sheets. Daryl refers to it as hard solder.. It comes in 4 flow temps.
• Extra-easy (56% Ag) flow temp.: 1,207°F
• Easy (65% Ag) flow temp.: 1,325°F
• Medium (70% Ag) flow temp.: 1,360°F
• Hard (75% Ag) flow temp.: 1,450°F
I can highly recommend it. Flows like water with a borax based flux   I use the extra easy with the borax based Handy flux, and propane or mapp depending on size of the job.
Rio-Grande is a good source for both flux and solder.
I use Brownells Hi-force for my soft soldering jobs. flows around 440 degrees and is stronger than most plain soft solders

Steve

[Dphariss]

Don't buy the paste type silver solder (solder and flux in tube/syringe from Rio Grande. Very short shelf life and once it gets old its useless. Get the wire and flux it always works. 1100-1200F flow temp is strong enough. If I need more I use brass. They also sell "silver solder" that is yellow for gold and cannot be easily seen on brass parts.

[Goo]

I think you should try to find a class in your area that will teach you about soldering, brazing and welding.   It is very important to be safe
 and learn the safety protocols for what you are working with.  Save up and get a professional torch set up with good quality gauges from the welding supply. Build a business relationship with them for help and advice.  It is very tempting to try and save money by using mapp gas.  The home improvement store  setups hat seem affordable actuality cost much more in the long run and you dont really save anything by going that route.

[Eric Kettenburg]

What Dan said above; Rio has a silver solder that will dead-on match typical yellow brass furnishings, and even when aged or tarnished is indistinguishable in color.  VERY useful in our particular sphere of work.  I'll have to see if I still have the part number or something on the package and will post it.  I picked up on it from a post someone made here years ago.  Just fantastic stuff.

[sbowman]

 i looked up the stuff Dan and Eric are referring to, Item number 503502 at rio grande. flows at 1100 to 1500 degrees, requires same flux i use.

This .010"-thick sheet of cadmium-free base metal solder produces a yellow joint that is ideally suited to yellow gold-filled, brass and bronze pieces. Cut the solder into pieces of whatever size each job requires, and use it with a hard soldering flux. Sheet solder makes it easy to cut a variety of custom sizes for a wide range of tasks and work piece sizes and shapes.

Steve

[Daryl]

I have always used a borax & water paste for flux for all of my high temp silver soldering.
The plastic bottle of flux I bought at the welding shop, was a borax paste. Virtually the same
as I made up for myself.

[davec2]

If you are trying to match brass color, here is an old post of mine about the Rio braze alloy......

https://americanlongrifles.org/forum/index.php?topic=24222.msg232336#msg232336

But I think you were asking about silver brazing steel......?

DaveC2

[mgbruch]

Thank you all. I appreciate the info.  Yes, I'm joining mild steel; for butt plates and trigger guards.

[Wandering longhunter]

I use 45% silver solder and Sta-Silv flux.








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