From: "Barry L. Ornitz" <ornitzz@dpnet.net>
Newsgroups: rec.crafts.metalworking
Subject: Re: stainless soldering
Date: Fri, 1 Oct 1999 21:11:09 -0400

eddie@nospam.iamerica.net wrote in message ...
>i have a little project where i'm soldering 24ga stainless tubing
>to 1/8" copper.  (i need an electrical connection.)  my materials
>vendor suggested harris stay-silv Black flux and 50/50 solid
>core solder.
>
>can anyone suggest a different flux or solder?


Does the application involve food or drink in any way?  Most stainless
solders used to contain cadmium which is great to improve the wetting of
the stainless surface, but it is quite toxic when leached out into food or
water.

Ordinary lead/tin solder will often work if the stainless surface is
cleaned of oxides first.  Remember that stainless gets its name from the
fact that surface oxides protect the underlying metal from corrosion, much
in the same way that aluminum does.  An acid flux will be needed to
dissolve additional oxides that form during the soldering process.  A drop
of hydrochloric (muriatic) acid applied simultaneously with the solder to
the already heated surface is normally sufficient.  Do not breathe the
fumes and work outdoors if possible.

If you have trouble with this, try the Harris Stay-Brite solder which is a
tin/silver alloy.  It will require about 550 F to melt and flow properly.
Again you will need an acid flux, and the same precautions apply.  In both
cases, wash the joint with water afterward to remove any excess acid
residue.

For a much higher strength joint, you will need to use a silver brazing
alloy such as Harris Stay--Silv 15.  This will require a torch as a
temperature of at least 1500 F will be needed.  Your present flux should
work with this silver brazing alloy.

        Barry L. Ornitz     ornitz-at-dpnet.net