Soldering stainless steel wire

As I (and others) mentioned earlier, it is easy to solder to stainless steel with phosphoric acid as a flux. I have done it many times with excellent results. Brazing then soldering also works well.

John

Why do people keep saying that you can not solder stainless steel?

when I have been doing it for ages and directions such as this exist.

Soft Soldering

All grades of stainless steel can be soldered with lead-tin soft solder. Leaded solders should not be used when the product being soldered is used for food processing, serving or transport. Soldered joints are relatively weak compared to the strength of the steel, so this method should not be used where the mechanical strength is dependent upon the soldered joint. Strength can be added if the edges are first lock-seamed, spot welded or riveted. In general welding is always preferable to soldering. Recommended Procedure for Soldering

Recommended procedure for soldering:

? 1. The steel surfaces must be clean and free of oxidation.

? 2. A rough surface improves adherence of the solder, so roughening with grinding wheel, file or coarse abrasive paper is recommended.

? 3. Use a phosphoric acid based flux. Hydrochloric acid based fluxes require neutralising after soldering as any remnant traces will be highly corrosive to the steel. Hydrochloric acid based fluxes are not recommended for soldering of stainless steels.

? 4. Flux should be applied with a brush, to only the area being soldered.

? 5. A large, hot iron is recommended. Use the same temperature as for carbon steel, but a longer time will be required because of stainless steel's low thermal conductivity.

? 6. Any type of solder can be used, but at least 50% tin is recommended. Solder with 60-70% tin and 30-40% lead has a better colour match and greater strength.

I was interested in hearing that you can solder to SS. I did not know that and am glad to know. In machining, solder is frequently used for joining - if the contact area is fairly large or flat, the shear strength of the joint is high. I machine SS 304, 316, and 303. I do deep hole drilling with or without 4000 psi coolant feed (made from an airless paint sprayer), and various turning operations. The 303 is "free machining" due to some sulfur content, so not sure if it would solder. But, given the chrome content, I am surprised at the solderability. jb

Thanks, George. I saw your earlier post but lost it. I appreciate your repeating it.

Cheers, John S

Yes. Heat buildup is the culprit here. Spot welding works well because of the small spot generating the heat necessary to create the weld. The speed of the process helps as well.

that

wire

buy

solder?

IME braze and solder works better than crimping by a little bit. SS is rather difficult to crimp well.

?-)