On Sat, 13 Dec 2003 20:36:46 GMT, Don Bruder wrote:
Well, first thing is that you don't solder steel or aluminum. Period.

I do both routinely. Just buy the right solder.

I like Harris Staybrite, a low-temp silver-tin alloy for steel,
stainless, brass, bronze, copper and every other metal I've tried it
on other than aluminum. I don't recall the working temp but it's
under 500F. A soldering gun or iron or propane torch works fine.
It readily wets any of the metals I mentioned and it's quite strong
-- 24,000 PSI IIRC. It would be good for art work because it's
color match with steel and stainless is very good. Flux is ordinary
tinner's fluid.

For aluminum solder that works beautifully, , two sources: Aladdin
and TinManTechnology. ESAB #31 also works well. It's closer to
brazing, but the stuff works like magic on thin aluminum, wets and
flows almost like silversolder does on brass. I've made joints with
thinwall tubing thru thin plate by fluxing the joint, placing a
preform ring of solder at the joint and heating the work until the
solder melted and the joint made itself with a nice fillet. I have
photos if you doubt it.

It must be used with companion #31 flux. Both are available from
W.W. Grainger.