Silver Soldering SS

[schmeky]

Can you solder silver stainless steel? I need to silver solder a low stress item on a pistol. I can silver solder copper like no body's business, but have never done SS.

What do I need?

 

[Pokyman]

You can silver solder stainless, but is very hard to do. Start by using a low temperature (relatively speaking) solder. The thing that makes stainless so hard to silver solder is that if you use an acetylene torch, the flame deposits contaminants in the braze area. When that happens, it is almost impossible to get a good looking joint. Before you try to silver solder on the real thing I would suggest some practice on some stainless that it doesn't matter if you screw it up.

 

[Zeke/PA]

I have used vastly in the past a solder marketed by the Eutectic Corp designated as 157 B.
It is a food grade material and can be used to join both stainless and/or dissimiliar metals with ease.
The flow point is 450 degrees F and the tensile strength is somewhere around 45 thousand psi.
A propane torch, depending on the size of the part , will do fine.
When soldering, NEVER apply heat directly on the joint as the flux is burned away and a good clean solder flow will not occur.

 

[schmeky]

Great information. I have an oxy/acetylene rig and a propane torch. Sounds like I need to use the propane for a clean flame. I'll get some of the 157B flux and some appropriate wire and do some practice joints first.

 

[Zeke/PA]

schmeky,
The Eutectic flux is on the corrosive side and once the job is complete, the joint should be neutralized.
A solution of water and baking soda works well.
A beaker on my bench contains about 2 qts. of water and enough soda so that no more will disolve.

 

[dfariswheel]

If its flowing at 450 degrees, its not a true silver solder (silver braze), its a soft solder.
True silver solders start to melt up around 1100 degrees.

Brownell's sell true high-temp silver solders that can be used on stainless, and refrigeration supply houses sell silver solder and a non-sliver "silver braze" used on stainless refrigeration tubing, along with the special flux.