On Friday, August 7, 2015 at 10:59:32 AM UTC-7, Cydrome Leader wrote:
Ed Huntress wrote:
On Thu, 6 Aug 2015 18:07:14 -0700 (PDT), "
wrote:

On Thursday, August 6, 2015 at 3:18:09 PM UTC-4, Cydrome Leader wrote:

Obviously both can and do work. Any ideas on why one might use a silver
solder vs the 50/50 stuff?

Never thought about the fixer eating silver from silver bearing solder.
The guy that made the sink has been making these for decades and knows
what he's doing.

It is true the "factory" solder doesn't match the color of the stainless
at all and is dark grey/nearly black. but it has has in fact lasted what I
suspect to be decades already, and I've seen a bunch of the sinks made by
that company.

There is cracking of the solder in other areas that do not actually get
wet, and I was assured that they can be touched up and reflowed if I'm
familiar with soldering.

So, it's soft-solder. If you apply flux anywhere that gets wet, it might matter
how you passivate afterward (even stainless is attacked by some photographic
chemicals, if you don't treat the surface - passivate it). Any effective
solder flux will damage the existing passivation.

Oxidizing acid (dilute nitric, or maybe citric) is typically used to passivate stainless steel.