View Full Version : Solder aluminum?

David Hafnorske
10-23-2002, 09:55 PM
I thought I saw in a catalog one time that they were advertising an amazing new solder. One that would solder just about anything, even aluminum. Well now I have a project that I wish I could use it on, but I never ordered any. Is this possible???!! has any of you ever done it? Any info would be helpful. Thanks

10-23-2002, 10:10 PM
There have been couple previous postings about this.

It's good for filling cracks and such but I would never use this for anything structural. I've used it before and frankly I'm not impressed. It's quite sensitive to temperature and unlike brazing or soldering, it doesn't wet the aluminum very well, which explains why the "soldered" joint isn't very strong.


10-23-2002, 10:52 PM
Mnay years (at least 55) ago I soldered aluminum to copper with lead solder. Rick was If I remember correctly, to flux well, make a puddle of solder, scrape the oxide off the Aluminum under (through) the puddle so air never got to the aluminum. The method was writtine up in old Mechanix illustrated, pop mechs or some such magazine. Best I remember it held and made a good ground, looked bad. Iwas building a transmitter from war surplus radio equipment and had few tools and a dollar was big as a cart wheel to me so my standards may have been a tad low. Have not tried it since. I think today I might use a wire brush (iron) if i were desperate enough.

Those miracle welding rods and solder never seem to help me. Aluminum is very active and oxidizes almost immediatley even at room temp. The oxide would have to be removed (thus the wire brush underthe solder pool. I second rotate about not trusting the miracle stuff, and I have tried it also. Its not even very good cosmetic wise. About as soon use bondo for filler for looks.

10-23-2002, 10:54 PM
did a double post sorry!

[This message has been edited by docsteve66 (edited 10-23-2002).]

10-24-2002, 12:06 AM
The solder sold today for Alumium ins totaly Lead or Antimony free (or it won't work). But save your money, a super glue with a properly preped and primed surface is almost as strong as the metal - ask Boeing, they shave thousands of pounds of weight off a jet with proper application of cyanoacrylate glues. The big difference between what they buy and what you buy is they get the extra pure stuff and you get crap. To extend the life of these glues place a small bag of dessicant in a sealed bottle (large pill bottles) with the glue to slow damage from moisture once opened. It is best to buy small batches and use them up fast to minimise and reduce loss of bonding strength from deterioration.

If you need to join Aluminum use a TIG welder or gas weld it (if you are that good, what the hell would you solder it for?).

10-24-2002, 10:40 PM

you forgot to mention that some of this stuff is stored at precisely say -40 F with only +/- 5* for only a few days.

10-25-2002, 01:18 PM
on "super glue (CA). Thrud is correct buy small, keep it dry. The moisure in the air (When you have a squeeze bottle) is sufficient to start the process of thickening the glue and rendering it useless. As trap says- we stored the stuff at low temps, used it fast once the first drop was removed (within days).
So Now I buy small tubes, ones that roll up so no air is sucked back into the tube, and if asample (on a test plate) is losing strenght, discard it. Is also (in my experience- Doctors says don't do it) better than a stitch for holding a cut together. Course I used to use plastic electricians tape so maybe I am not to be copied.

George Hodge
10-25-2002, 09:50 PM
Try storeing your super glue in a sealable plastic bag,with the air squeezed out.

10-25-2002, 11:09 PM
Docsteve66- My doc actually suggested superglue for splits in the fingertips, and it's getting to be that time of year.

10-25-2002, 11:45 PM
Daughter says its good for split finger nails also.

I DO NOT advise using super glue for elecrical connections which is why i did my soldering. I suspect the current flow would be low, and if a ground you might even feel a voltage drop http://bbs.homeshopmachinist.net//smile.gif

Randy Powell
10-26-2002, 03:05 AM
Hi folks,

I'm new here. First post in fact. If you buy super glue, get it from a hobby retailer, not the stuff at the grocery store. It will work better (be more potent) and you can get what you need. There are special compsitions that will glue rubber, plastic or metal along with wood. Pacer makes some stuff called Zap that works quite well.

Randy (the model plane builder)

10-26-2002, 05:15 PM
Randy: I have friend who builds models, multiengine etc. He confirms that modelers CA is better quality, but you modlers USE it. I store it till it goes bad http://bbs.homeshopmachinist.net//smile.gif (excepting a drop or two). For me small and expensive lasts longer and is cheaper!>

Alistair Hosie
10-26-2002, 05:24 PM
Last time I was in Florida I was at a big fleemarket a guy sold me some solder sticks said to solder aluminum .He went on to show it welding holes in cola cans filled big holes.
(thats me)
paid handsomely for it I bought over $50 bucks worth as I believed it would work guess what i still have it here what a pile of crap .At least I cant get it to do anything.Alistair

10-26-2002, 07:39 PM
It is customary to buy swamp land - NOT Aluminun Solder in Florida! http://bbs.homeshopmachinist.net//biggrin.gif (titter, titter)


Lee Valley Tools sells a small can of Argon - used to force air out of opened wood finish containers to extend their shelf life. Works great, but a wee expensive. Mind you, some of the oil finishes are not that cheap either so, what the hell. Since Argon is inert and heavy it displaces the air easily. If you have a TIG welder on Argon you could just give it a shot from that!

Damn I am good, for what I have no idea... http://bbs.homeshopmachinist.net//biggrin.gif

ooH! ooH! Lee Valley also has Kolsch German Beer glasses - for you purists out there. Stick 'em in the fridge and serve your Grasshopper (German Beer made in Calgary, AB)ice cold like a man... Makes good glasses for bubbly too - keeps it more effervescient than normal champagne glasses. http://bbs.homeshopmachinist.net//biggrin.gif

Dave Burnett
10-26-2002, 08:17 PM
I bought some of that Aluminun rod too. It works great for filling holes in pop or beer cans but thats about all. If any of you guys need to fill any holes in beer or pop cans let me know and I'll give you the rod to do it with.

10-27-2002, 07:13 PM
Naw, Dave B, I still have a chunk lefft over from visiting a fla market in Florida also. Alistair and I aint biting. Will sell mine for .05$ plus postage http://bbs.homeshopmachinist.net//smile.gif. Also have some mountain land here in Florida.

I have no idea how much money I have spent, just to learn how the trick was done. The guy I saw made decent looking joints, I figured it was worth while to play with the stuff. He used (if memory serves) a butane torch. I watched long time for anlges, temps (guesstimates) etc. I swear I did it like he did!!!!. I did it all different ways. looked like i used bubble gum!!!.

Would still buy another stick if he would let me try it under supervision. VENDETTA TIME! I don't care if it is strong or not. Just can't believe I was suckered.
Also (at air craft show at tampa) they had a abrasive wheel, I watchedthe guy cut files, time after time. Did not believe what I saw , so I bought 3 or four. What ever I bought never got through a Nicholson file. I doubt that he had annealed to files- fraud.

who said he was self tought, a good studentwith a poor teacher? http://bbs.homeshopmachinist.net//smile.gif Thats me !

10-27-2002, 08:02 PM
There is an old trick foe soldering to aluminum (and other materials) that I have seen, but never tried. Load a wire brush wheel with solder by running it against a piece of bar solder. Then heavily wire brush the area you want to solder. This will scrub off the oxide and deposit a coating of solder on the material. Then you solder in the conventional way. I have never tried it, but the demo I saw looked pretty impressive.

David Hafnorske
10-28-2002, 09:18 PM
Docsteve66 .05$ for how much? I would like to get my hands on some just to try. Not interested in the land, unless of course you would swap it for some ocean front property in Arizona.

10-28-2002, 11:40 PM
David Hafnorske: I have no idea where i left it. But I was at home depot today, they are selling it, two sticks for about 4 dollars. Pre fluxed (blue if I remember right). What part of Az? I graduated high school in Tolleson, attended schools in Cold water, Mesa, Yuma, Gila Bend plus more in Az.

10-29-2002, 12:41 AM
Hey, what's this about aluminum solder not working? I got a coil of it and some flux long ago.

I have soldered quite a few pieces of aluminum together with the stuff, using a propane torch.
Dang near melted the aluminum a couple times, but it worked fine.

I got it at the hardware store, and it is NOT a tin-lead solder, it is something lighter. No idea what.

10-29-2002, 01:55 AM

There are actually two type of aluminum solder that I'm familiar with. The most popular is stuff that you see at flea market where they show off how well it works on aluminum beer can. Their favourite example is cracked aluminum propeller which has been soldered. This stuff is light and does not require any flux. Just clean the surface with SS brush and start rubbing it. It melts and creates a puddle which doesn't wet the aluminum very well. More often than not it creates a cold solder joint.

There is the second kind that uses flux and the "solder" is much thinner and is usually sold coiled up in a small plastic container. This stuff is very expensive and HVAC folks use it to join copper and aluminum pipes in air conditioning units. I've never use it myself but I've seen it use and this stuff wets very nicely and obviously creates air tight seal, however I got the impression that it's a relatively soft material so not suitable for any structural.

All of these so called aluminum solder is of very limited use. I've heard of aluminum brazing which is suppose to be pretty good.


10-29-2002, 09:43 AM
Well, I have the coil stuff, and if that makes a soft, non-sructural joint, someone will have to break the news to the structural joints I have made, some of which have lasted 20 years of reasonable stress (as much as the material would stand that was connected)

I used it for structural joins in equipment, and the joints seemed more like a brazed joint, not at all like soft solder.

10-29-2002, 10:05 AM

I must bow to your first hand experience with the coiled type of solder since I've only seen it used by another person. Just curious, was this a low temperature solder that you used? By that I mean, can you use regular propane torch? I'm wondering if what you used was a brazing wire?

You've certainly piqued my interest in the stuff that you have used. Do you remember where you bought it or what the name of the product was. Thanks.


David Hafnorske
10-29-2002, 07:48 PM
Docsteve66, just kidding, I used a line from George Straight

David Hafnorske
10-29-2002, 07:54 PM
Thanks for the info guys. I didn't realize you could buy it off the shelf. I'll have to check the hardware stores. http://bbs.homeshopmachinist.net//smile.gif

10-29-2002, 11:06 PM
Nope, do not remember, and the plastic package is long gone. Even the hardware store I got it at is gone. All I have is the coil of solder.

But yes, propane torch worked fine.

11-04-2002, 05:11 PM
the person with the magic solder made it all the way to the Denver flea market this summer. while at his stand, I saw a jar that resembled Vaseline with sand mixed in,although I did not ask him, I really think that was what it was.

11-08-2002, 12:10 PM
Good luck. I've seen the rod you're talking about on the web. The instructions there (I can't remember the site address now)are specific, you have to clean the aluminum with a stainless steel brush, and don't put the flame of the torch on the rod. You heat the aluminum then apply the rod to the heated surface. I've never actually used the stuff and was thinking about trying some, now I think I'll wait a while. Right after I close this deal on the Brooklyn bridge. Again good luck and let us know how it works out.