YAPH coughed up some electrons that declared:

I recently had a job in a place that had a lot of stainless steel pipe in
its plumbing systems. I think it must have dated from the copper shortages
of the 1970s(?) (connected with the Rhodesia crisis?). What surprised me
was that many of the joints were soldered, with regular-looking Yorkshire
(solder-ring) fittings. I tried tinning a bit of stainless pipe but
couldn't get the solder to wet the pipe. How does one do it - presumably
some special sort of flux?



Baker's fluid?

I've used that to solder stainless, but small stuff, not pipes.

I was a bugger to do IIRC. There's probably a better flux for the job, but
that's all I had to hand and it sort of worked...

Cheers

Tim