Silver solder use

[raddksn]

I was gifted this silver solder from some HVAC guys on a job. They obviously were using it for copper line sets. My question is will this work with steel? I have a mower deck I need to patch some rust holes, I will be cutting out the rust and thin areas and placing patches over (not trying a but joint) the good metal.
I’ve had this around my garage for years, I do zero HVAC stuff but would like to use this for something! Thanks for any advice or suggestions!

 

[rlitman]

That's copper-phosphorus rod. Not recommended for ferrous metal brazing. The 15 is I think a couple of bucks a stick now. I'd suggest you sell it locally and buy the right rod.

 

[dogdog]

I think stay-silv 15 , 6 etc is represent for percentage of silver. Dunno if they are used for metal but if it is you will need high temp flux with it for any other metal other than copper I think. And it’s not for drinking waters because of some thing in there that is carcinogen. Used that to make and odd ball brass adapter 1” npt male to 3/8 npt female from two different brass parts.

I have used the stay-silv 45 and 56 to repair my glass with a #3 air acetylene tip, with the black high temp flux. Still holding fine after 5 years.

 

[nadogail]

With the right heat and a good flux, IMHO it should work.
Any Technical Information you get from me is absolutely guaranteed to be worth exactly what you have aid me for it, send a self addressed stamped envelope and your check will be mailed to you.

 

[Firebrick43]

Unfortunately no, they are only for copper to copper or copper alloys.

The silver content has to be over 30 for steel but 45 or 56 works much better.

Silver brazing is real expensive with no upside to patching steel over a silicon bronze rod which is much cheaper.

Silver brazing is for very close fit ups, items that might be overheated, or for joining dissimilar metals or even carbide to steel

 

[MoonRise]

Both of those Harris Stay-Silv brazing fillers are used for brazing copper or copper-based alloys (aka brass).

They are NOT for use on steel or nickel, as the phosphorous that is helpful/necessary for brazing on copper is BAD for steel. When used on copper, the phosphorous makes the rod self-fluxing (although some extra flux is sometimes needed or necessary).

From a Harris catalog:
These brazing filler metals are primarily used to join copper to copper, copper to brass, and brass to brass. The phosphorus content serves as a “self-fluxing” agent in joining copper to copper. When brazing brass to copper or brass to brass, use Stay-Silv® White Brazing Flux. The phos/copper and silver/phos/copper filler metals are not recommended for brazing steel or nickel alloys.

And indeed the "6" and the "15" in the product names refer to the silver percentage in the brazing filler alloy.

For brazing on steel, you would typically use something like a low-fuming bronze brazing rod. Flux is required in this application, either a flux-coated rod and/or with externally applied separate flux.

 

[raddksn]

Both of those Harris Stay-Silv brazing fillers are used for brazing copper or copper-based alloys (aka brass).

They are NOT for use on steel or nickel, as the phosphorous that is helpful/necessary for brazing on copper is BAD for steel. When used on copper, the phosphorous makes the rod self-fluxing (although some extra flux is sometimes needed or necessary).



And indeed the "6" and the "15" in the product names refer to the silver percentage in the brazing filler alloy.

For brazing on steel, you would typically use something like a low-fuming bronze brazing rod. Flux is required in this application, either a flux-coated rod and/or with externally applied separate flux.

That says it all! Thanks!

 

[raddksn]

Unfortunately no, they are only for copper to copper or copper alloys.

The silver content has to be over 30 for steel but 45 or 56 works much better.

Silver brazing is real expensive with no upside to patching steel over a silicon bronze rod which is much cheaper.

Silver brazing is for very close fit ups, items that might be overheated, or for joining dissimilar metals or even carbide to steel

Good info thanks!

 

[fitter30]

Are is it dyna flow that replaces 15%. Not soft solder flux but !
Mapp gas is a minimum. And to fill take alot of experience to fill with it to control the heat there is a fine line.

Amazon.com

 

[lilredex]

It is mainly used for jewellery and other close fitting joints. I have used it for repairing glasses, and joining steel parts which make machining a lot less time consuming. Don't ask which silver solder it is, found it rolling around in a parking lot years ago.

Not going to work on lawnmowers....get it brazed (O/A).