Solder stainless?

silver solder will work

Solder: Harris StayBright Flux: Harris StayKleen

A good welding supply shop will have them.

Soft solder (even the lead-free stuff) will stick if you use an appropriate acid flux (look for 'Stainless Steel' flux); same flux works for brass and for stainless, it IS corrosive, don't get it on skin.

Silver solder is (just barely) possible, but risks melting the brass.

Usually, a brass fitting just rests in some plumber's putty or adhesive sealant. Why do you want solder?

Food contact? 95-5 tin antimony, with a stainless-steel (highly agressive) flux. Be sure to throughly rinse/wash to remove all flux when done. Works if not food contact, too. Other solders work, as does silver brazing (brazing flux being, hopefully obviously, different than soldering flux). It's mostly about choosing a flux aggressive enough to allow the stainless to be wetted for a good job.

Staybrite, which is tin-silver, wets stainless very readily and is food-safe. Ordinary tinner's fluid works fine for flux. Operating temp is 430F.

( Snip)

Have a look at this on Utube first, it looks too good to be true. I wish I'd known about it years ago. Durafix Easyweld - making aluminium welding easy

Have you actually had good results with this stuff? I've seen the demos at shows and such, but I've not found the stuff to be at all useful in my shop. I've found that joints made with it aren't much stronger than joints made with epoxy.

Successfully soldered the copper fitting to the stainless bin.

All looked great until one or two spots at the seam wouldn't "flow" the solder (stubborn oxidation). So after heating to point of getting the solder liquid I squirted some liquid flux on the spot and ... voila! The spot apparently cleaned up immediately and the solder flowed right over the spot.

It's nice when things come together..