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numbbers · Posted: Mon Feb 02, 2004 9:26 am Post subject: Hey Welder

Are you really a welder? I need to weld/braze copper sheet to aluminum. Can that be done?
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1980 924 Turbo

CBass · Joined: 03 Nov 2002 Posts: 2807 Location: Vancouver, Canada

I'm a welding student, and I've never heard of anyone welding copper to aluminum. You might be able to do it with a braze, but I don't know what you'd use as a flux or a rod.

I'll ask my instructor at school tomorrow morning.
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'81 931 in various states of assembly

Mikri184 · Joined: 12 Sep 2003 Posts: 746 Location: Ferndale, WA

Yep, you can braze it or soder it.
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Life is to short to be looking for something?

Smoothie · Posted: Tue Feb 03, 2004 9:04 am Post subject:

Check out "AlumiWeld" ("Alumaloy") at - http://virtual-adnet.com/
I saw it demo'ed in an infomercial a couple months ago and it looks real good. Other info and posts on discussion groups confirm what was shown and said about it. It's done with just a propane torch - no special welding or brazing equipment. It's definitely good for aluminum, but they also mention repairing automotive radiators and marine brass/bronze fittings. Tensile strength = 47,000 lbs./sq. in.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

welder · Joined: 16 May 2003 Posts: 158 Location: cumberland,maine

Numbbers, yes I weld for a living, for someone else and do aviation welding for my own bussiness. To answer your question, yes you can both weld and solder / braze copper to aluminum. Be aware this has limited application and is very hard to do. The easiest is to tig weld using aluminum bronze, silicon bronze,,manganese bronze, or some such filler material (which there are numerous types). This will work for material about 1/16 of an inch thick or thicker. Although when you are talking thinner material such as very, very, thin sheet metal the skill involved is much greater. This can be done by hand though, your material is so thin that all margen for error is very small and your pieces will just blow away. Idealy you would use a low temp alloy that would melt before the copper or aluminum and would be compatiable with both. Very thin aluminum under any welding, or brazing process can be a bitch if you are not used to working with it . My suggestion would be to go to (and take the pieces with you) to a weld supply company and they will gladly pick out a suitable and compatiable filler material for your application or suggest an alternative process that will work and save you money. They have a line on the best welders in town too. Many times in a manufacturing atmosphere, when brazing thin aluminum and copper/brass , it's done in ovens to control tempeture.
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I have a 78 n\a currently under restoration.

numbbers · Posted: Tue Feb 03, 2004 10:54 am Post subject:

Thanks all.
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1980 924 Turbo

CBass · Joined: 03 Nov 2002 Posts: 2807 Location: Vancouver, Canada

I'd be interested to know how you can get good fusion with that alumiweld, if you're not melting the base metal... It says it has 40K+ PSI tensile strength, and that it's stronger than the parent metal, but I don't see how the joint could be strong enough if it's not even fusing the base metals.
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'81 931 in various states of assembly

geezergary · Joined: 07 Nov 2002 Posts: 80 Location: sask.ca

You may want to check out some adhesives. I've seen some
good ones but you will need some overlap of material and they
are not cheap! The samples I saw at a car show were impresive.

Alex Roy · Posted: Wed Feb 04, 2004 4:02 am Post subject:

If it's not melting the base metal, then it's just soldering or brazing.

welder · Joined: 16 May 2003 Posts: 158 Location: cumberland,maine

Correct Alex, if there is no melting of the parent metal it's soldering or brazing. Although, there are some very sophisticated high and low temp soldering/brazing filler materials. These alloy mixes provide great adheasion, , decent wear qualities, and resist cracking. The "alumi-weld" Smoothie spoke of is very commom now and is mostly used to braze "pot-metal" or white metal and is a good product. I cannot say what it's actual tensile strenght is though. I've used it and I know it can be drilled and tapped so it's reasonably strong. Yes it's melted with a low temp propane torch.
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I have a 78 n\a currently under restoration.