Silver soldering stainless steel

Aplologies if this has been answered before, but the only thread I've been able to find related to the pre cadmium ban days.

Question is - can I silver solder stainless steel with Silverflo 55 / Tenacity 5, which is what I've got? The steel is probably 304 18/10 being derived from cheap cookware.

Robin.

Hello Robin, you will have no problems in using SilverFlo 55 with Tenacity 5 on St St. The usual strictures regarding thorough cleaning apply of course. You may also find it useful to mix the SilverFlo with meths or better still, surgical spirit.

Brian

Thanks Brian, that's what I was hoping to hear but didn't know if T5 was sufficiently aggressive.

I've read about using meths rather than water before - I've also seen recommendations to add a drop of detergent to the mix. Presumably this is to do with surface tension/wettability when applying the flux? I've not had any problems using plain water when soldering brass of MS, but I'll give it a go.

Robin

The thing about using meths or surgical spirit is that the solvent burns as soon as a flame is applied and has the effect of making the flux adhere rather than running off as it does with water.

Rolls Royce aircraft engine specifications used to recommend the use of a drop of washing up liquid and this can be helpful but only a tiny drop is needed. They also recommended surgical spirit so as not to contaminate the joint with meths but meths works perfectly well.

Brian

Edited By Brian Hutchings on 20/08/2017 22:45:40

As someone who uses upward of a hundred pounds worth a week....do add washing up liquid but only a fraction of a drop as it turns black and 'burns' if too much is added. People state that the ss will only flow where you apply flux - totally untrue, the flux melts and flows all over the place! The joint needs to be debris free but requires no additional surface cleaning so long as it is just bare metal, the flux will remove all oxide contaminants. T5 is fine for stainless but you have to get it plenty hot, and remember that it will only work for a finite time. Good luck