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Low-temp flux for soldering stainless steel

July 24, 2018

Q. Hello!

I want to include stainless steel parts in some stained glass art I'm designing and will make.

I've seen low-temp fluxes that seem to be mainly a blend of "regular" flux (the sort used for soldering copper with tin-based solder when making stained glass art) plus some hydrochloric acid, a.k.a. "muriatic acid", to etch the steel. -- As a note, yes, I do have some silver-solder paste, and it works great on steel-to-steel sections, but I can't use it with glass because, to make a long story short, I end up ruining the glass.

So, here is my question:
Can I use make a concentrated citric acid ⇦this on eBay or Amazon [affil links] solution to score just the part I want to solder, then immediately add regular flux, and then use tin or lead+tin solder, and get it to "stick"?

I have citric acid crystals and am familiar with using the stuff, so I figured I'd ask. I also have liquid "muriatic acid" for the pool, but I would really prefer to not fool around with the gallon bottles just to use a few drops.

Also, I realize that the joints will be far weaker than if I silver-soldered them all, and I also realize that any form of soldering or brazing is weaker than welding, but these are just decorative stained-glass items, not anything requiring industrial levels of support strength.

Thank you for any info!

Kris Krieger
hobbyist/artisan - Richmond, Texas, USA