Subject: welding Al

From: [email-masked] (Howard Anders)
Date: Mon, 1 Nov 1993 04:59:59 GMT

My apologies if this has been asked before, but I'm new to this group &
haven't seen anything on this before. Question simply is, is it feasible
to weld Aluminium raesonably satisfactorily with oxy/acet, as I don't have
and can't afford gas shielded equipment, even though that is the "right'
way to do it of course. What fluxes does one use? What techniques does one
use to avoid flux entrapment? Any other advice would be appreciated.
(I have a "stick" welder, but I have not been able to get Al stick
electrodes here, and I understand you need DC to run them??)
p.s. is there a FAQ for this group??

---

From: [email-masked] (ron ginger)
Date: 1 Nov 1993 13:35:55 GMT

In article <[email-masked]>, [email-masked] (Howard Anders) writes:
|>My apologies if this has been asked before, but I'm new to this group &
|>haven't seen anything on this before. Question simply is, is it feasible
|>to weld Aluminium raesonably satisfactorily with oxy/acet, as I don't have
|>and can't afford gas shielded equipment, even though that is the "right'
|>way to do it of course. What fluxes does one use? What techniques does one
|>use to avoid flux entrapment? Any other advice would be appreciated.
|>(I have a "stick" welder, but I have not been able to get Al stick
|>electrodes here, and I understand you need DC to run them??)
|>p.s. is there a FAQ for this group??
|>
|
There is a rod availalbe for welding, or more correctly I think Brazing, 
aluminum. I bought a pack at an engine show, but I have seen it listed in some
of the tool catalogs.

It is a bit tricky to use. You basically heat the base metal and flow on some
of the rod. Then you use a stainless steel scraper to scrape the base metal 
under the pool of molten rod. You will see an oxide float to the surface.

I used it to make a small sanding disk, where I brazed a hub onto a 3"dia disk.

The guy demoing it at the shows even joind alum beer cans together. He also
shows all manner of repaired castings etc.

ron ginger

---

From: [email-masked] (John De Armond)
Date: Tue, 02 Nov 93 07:05:26 GMT

>p.s. is there a FAQ for this group??

Aluminum can be welded with an acetylene torch.  It is tricky and it ain't
pretty but it is strong.  I can't give you much information on the special
rods I use because I bought 50 lbs of them 20 years ago and they're still
going strong.  The rod is a hollow aluminum tube filled with flux.  The 
flux is very active and enables welding even fairly cruddy metal.  
I used these rods for field expedient repair on racing engines and chassis
when I used to race motorcycles so this stuff IS strong.

The key to making it work is to heat the whole piece close to the softening
point of aluminum.  Then you could go in quickly with the flame, start a 
melt puddle and apply the rod as needed.  A quick in-and-out motion with the
flame makes a puddle that quickly solidifies before it can fall out.
Once a little flux is melted from the rod, the joint stays clean.

John

-- 
John De Armond, WD4OQC                   | For a free sample magazine, send
Performance Engineering Magazine(TM)     | a digest-size 52 cent SASE 
Marietta, Ga     "Hotrods'n'computers"   | (Domestic) to PO Box 669728
[email-masked]    "What could be better?" | Marietta, GA 30066
Email to me may be published at my sole discretion.

---

From: [email-masked] (Jeremy Ballard Bergsman)
Date: Tue, 2 Nov 93 23:45:38 GMT

Hello, I hope I am not out of order with this request.  Is anyone here
proficient in working with stainless steel, living in the San Francisco
Bay Area (Mountain View ideal), and willing to trade some instruction in
metalworking for some instruction or production in homebrewing of beer?
Please email as I don't read this newsgroup.  TIA.

Jeremy Bergsman
email:  [email-masked]

---

From: [email-masked] (Soren LaForce)
Date: Tue, 2 Nov 1993 22:57:00 GMT

In article <b#s1=[email-masked]>, [email-masked] (John De Armond) writes...
>>to weld Aluminium raesonably satisfactorily with oxy/acet, as I don't have

I believe that aluminmum can also be "brazed."  The local welding shop
stocks the rod and flux (Madco in mountian view, CA).

Haven't tried it myself.

--Soren            [email-masked]

---

From: [email-masked] (Kevin Martinez)
Date: Wed, 3 Nov 1993 06:10:39 GMT

In <[email-masked]> [email-masked] (Soren 

>--Soren            [email-masked]

If you really want to, you can gas weld aluminum with oxyacetylene. It's 
going to take some practice though. the "feel" is completely different than 
steel. It is slightly easier if you use hydrogen instead of acetylene.

You should go to a welding supply place and tell them what you are trying to 
do. They will set you up with al welding rod, aluminum welding flux and some 
kind of chemical cleaner (usually a mix of phosphoric and hydroflouric 
acids). In addition, you should seek out some didyium or cobalt blue welding 
glasses. Brush the surfaces you want to weld(vigorously) and apply cleaning 
solution. Mix up some flux with water or alcohol and then rinse the cleaning 
solution off with water and a brush. Apply flux solution liberally to the rod 
and the objects to be welded.

Preheating is essential, but you must experiment to find out how much. When 
you apply the flame to the Al, the flux will light up bright yellow. The blue 
glasses filter this and you can see whats going on. Don't attempt to "drip" 
the rod into the joint, you must tap where a puddle would be if it were 
steel.  You will feel when the Al is melting, the only thing you'll see is 
when it's too late and it has dropped out the back side! Back side support 
helps alot. When you're done, brush and scrub to remove flux. Polish it and 
pretend that you TIG welded it because it rarely looks as pretty.

Fend-all makes the blue welding glasses if you wish to try to recapture this 
lost art. 

Fend-all Company
5 E. College Dr.
Arlington Heights, IL
60004

I got #5s

Practice on something similar to what you want to weld before you touch it 
with a torch. You'll be much happier this way. Hope this helps... 
-- 
The Lottery is a Tax on those who can't do Math!
                               - heard on UseNet
Kevin Martinez
[email-masked]

---

From: [email-masked]
Date: 2 Nov 1993 08:20:25 GMT

In article <[email-masked]> [email-masked] (ron

>under the pool of molten rod. You will see an oxide float to the surface.

I have some of those rods but havent done much with them. From handling and
observation (and relating to material I learned in a 2 year Oxywelding tech
college course), these rods are very brittle and likely have a verh high
silicon content.

In the welding course we were taught how to, and did oxyweld various aluminium,
Al alloy objects. Its a bit of alchemy.  The correct rod to use depends on the
aluminium alloy and to some degree the way the Al has been processed/tempered.
The varius grades of rods have differing melting points, with the higher the
silicon content in the rod, the lower its mp.  There is a tradeoff, the higher
the Si content, the more brittle the weld metal.
The flux used was chosen by a a little trial/error. Generally we used
commercial (Comweld, an Aust brandname) Al flux that was essentially powdered
Sodium Flouride. We mixed it to a thin paste with either water or methylated
spirits.  
For some objects the water mixture worked perfectly, on other alloys the water
mix wouldnt do its job but the methylated spirit mix worked like a charm.
Basically you heated the job poking at it with the rod or a wooden stick.
Once the surface softened (you had to poke becuse the oxide covering usually
masked visible indication of the job being up to temperature), you worked
fairly quickly with careful heat or else you would have a big hole. 

Flux inclusion of the somewhat corrosive flux is a real problem ... Basically
avoid joints (e.g. overlaps) that encourage flux inclusion. We were told to
scrub the finished product with hot soapy water... Perhaps steam cleaning would
achieve similar results.

Overall oxywelding of Al is a bit of a work of art/skill. On the other hand 
its a cinch compared to playing with diecast (also known as sh*tmetal!).

Joe Miles                                  Email: [email-masked]
Microcomputer Support                      tel:   +61  6  249 2544 
Computer Services Centre                   fax:   +61  6  247 3425
The Australian National University
Canberra      ACT        0200