Soldering is done at much lower temperatures than brazing, below 800F.
 Principal soldering alloys are a combination of lead and tin.  Tin-antimony
 and tin-silver solders are used for food handling and other applications
 where lead would be objectionable.  Welding has largely replaced soft
 soldering of sheet metal assemblies as shops have become more skilled and
 familiar with welding light gage stainless steel sheet work assemblies.  The
 strength and durability of welded joints is considerably greater than that of
 properly soldered joints.  Nevertheless, soldered joints still find many
 applications in architecture, food processing and plumbing.

Sheet metal:  The 300 series stainless steels solder with relative ease
               although types 321 and 316 are somewhat more difficult to
               solder.

Surface finish:  Annealed and pickled finishes #1 and #2 or polished surfaces
              #3 and #4 are preferred to the brightly polished surfaces #7
              and #8.  Bright annealed finishes are difficult to solder.

Preparation:  Proper cleaning of the surface is the key to tight reliable
               soldered joints.
              1.  Remove all dirt, dust grease, scale, fingerprints, etc.
                   mechanically or with a proven commercial solvent.
              2.  Wipe clean with alcohol or other proven solvent.
              3.  Apply phosphoric acid based flux.
              4.  Tin the surface before assembling the joint.
              5.  Apply solder. See Item F in Joining Menu.

Cleaning after soldering:  All flux and solder residue must be removed from the
 surface by scrubbing in water, by chemical cleaning agents, or mechanically,
 or by some combination thereof in order to prevent corrosion in service.  An
 alkaline rinse late in the post-soldering cleaning cycle is very helpful in
 neutralizing acid residues.


Additional information on brazing stainless steel is available in:

     "Welding of Stainless Steels and Other Methods of Joining",
        available from NiDI, Literature Item 9 002.

     "Metals Handbook", Ninth Edition, Volume 6, Welding, Brazing
        and Soldering, Metals Park, Ohio  44073.