Subject: Re: Soldering aluminum bar stock

From: [email-masked] (Ron Ginger)
Date: Tue, 15 Nov 1994 21:22:44

In article <[email-masked]> [email-masked] (David Hoopes) writes:
>From: [email-masked] (David Hoopes)
>Subject: Re: Soldering aluminum bar stock
>Date: Tue, 15 Nov 1994 14:01:16 GMT

>[email-masked] ((P.) Brad Smith) writes:

>>In an attempt to build a stable jig for woodworking use, I need to
>>solder two pieces of 1/8" aluminum bar stock  together at a right
>>angle. The lead core solder (flux built in) that I tried to use just
>>balls up and rolls away, even with the surface roughed up. Can
>>aluminum be soldered at all? Do I need a different solder? Can someone
>>help end my cluelessness?

>I am in the process of designing a project that uses aluminum for a frame.
> I have been wondering the same thing.  Can aluminum be soldered, or is it
>possible to weld it?

Aluminum cannot be soldered with lead/tin solder.

It can be brazed with a special alum rod. This is often demoed at places like 
engine shows and fairs, where they sell it in small packs for $20. They 
usually demo soldering various alum parts,like lawn chairs and beer cans.

You can buy the rod at any good welder supply store, and for $20 you can get a 
large supply.

It can be done with a normal propane torch. I have used it for a few small 
parts. I have only moderate faith in it. Im not sure you get any really 
serious penetration. If the job was something of high strength, or serious 
consequences if it failed, Id get it TIG welded.

ron ginger

---

From: [email-masked] (David Erickson)
Date: 22 Nov 1994 01:16:26 GMT

In article <[email-masked]>,
Richard Tweedie <[email-masked]> wrote:
>
>While I personally have had almost no luck with soldering aluminum,
>excellent results have been had with a sort of brazing rod called
>Lumaweld.

>It melts below the temperature of the Aluminum alloys, is supposed to 
>work with 2s, 3003, 6061, etc., but not for 2024 or 7075.  I tried
>it with some success on 2024 T3, don't know if the resulting 
>strength, etc., is worthwhile.  Works great on 6061 T6.  There are
>more than one version of this stuff, so see what is appropriate for
>your use.

the secret to using the aluminum solders is cleanliness and technique.  I find
that using a wire brush on the aluminum prior to soldering gets it clean 
enough.  The technique I find most useful is to "scrub" the metal being soldered
with the solder.  The solder doesn't wet the joint readily, but it will pool 
and you can get good, strong joints.  Watch out, however - the solder
tends to dissolve the aluminum base metal, even though the base metal has a
higher melting point, so I guess this actually is welding, not brazing or
soldering!

-Dave Erickson