How To Solder Aluminum

[Sir Raleigh]

I Thought I'd post this here because soldering Lipo battery tabs seems as though it would be the most likely place where this procedure would come in handy.

I found this on the web and it seems to work...

"Tin the aluminum under oil, then solder as normal.

Aluminum normally won't accept regular solder. That's because
of the oxide coating on its surface. By covering the surface with
oil, you can scrape away the oxide coating while preventing oxygen
getting to the surface and reforming it. You can then tin the surface
with an iron, through the oil coating, and get a proper bond. Then
you can clean the oil off and solder as usual.

This is a home shop technique. There are probably better solutions
in a production environment."

Additional information:

Q: What kind of oil to use?
A: Mineral oil, but ordinary motor oil will work, although it smokes a bit.

[everydayflyer]

Bill , I noticed you posted this on atleast two different Users Groups. Just curious if you varified the process first?
If you have a soldering iron,solder,a piece of aluminum foil and a piece of say 24 ga. wired it would only take you 5 minutes to conduct a test. Why not post a photos of the results perhaps.


Charles

[worldraft]

I've tried to solder aluminum in all kind of ways but with no sucess.
I will try this today and come back to you all.

[buzkil]

I would say that the right flux would help, but I don't know about the oil theory. I sure would like to know though.

Try reading this to help understand a little about alluminum brazing and soldering. http://www.aws.org/wj/2004/02/046/

Or you could use this product. http://webapp1.cronatronwelding.com/...temNum=CW01017 you would still need flux either way.

[soar-ne]

I went to a welding supply house and got some Alum. flux paste. Made by Harris, use as with normal flux, seems to clean the oxidation or whatever off and the parts stick well. On lipo tabs use a hot iron and make the connection fast (2-3 seconds), any more and you can ruin the internal connection of the tab.

Good Luck
Bob

[Rodneh]

Yes this works (soldering under an oil coating) as I have done it. In fact, I was soldering a hole in a flat aluminum can so I made a damn of modeling clay around the area, filled the damned area with kerosene, scraped the area to be soldered with a knife blade then soldered the hole shut shut with plain old 60-40 solder. No, the kerosene did not burn but to be safe, I did do it outdoors. It does require that you use an iron with enough thermal mass so that the oil does not lower the iron temperature below soldering temps.

[Sir Raleigh]

Originally Posted by everydayflyer

Bill , I noticed you posted this on atleast two different Users Groups. Just curious if you varified the process first?
If you have a soldering iron,solder,a piece of aluminum foil and a piece of say 24 ga. wired it would only take you 5 minutes to conduct a test. Why not post a photos of the results perhaps.


Charles

I originally posted the suggestion on this thread: Lipo - rebuilding packs and the response from rhuber40 indicated he was successful in building up a few packs from some salvaged Lipo cells.

So, it has apparently been tested, just not by me.

Granted this is not the only way, and might not be the best way, but it does appear to work.

Charles, my hands are just too shaky to have any success in trying this plus my iron is just too small (20 or 30 watts, I think).

However, it does seem like others have had success using this, or a similar, procedure.

[everydayflyer]

Well I know for a fact that the last two items on this page work great

http://www.cheapbatterypacks.com/?sid=1006254&pgid=bldg

Several years ago I built packs from loose cells and have salvaged a couple of packs by converting from 3S to 2S.

No matter what ones tries to use on LiPolys I would suggest first practicing on aluminum foil and as mentioned learn to work fast. The seals are very easily damaged by heat. I use small clip on heat sinks myself such as the ones used for heat sensitive electronic components.


Charles

[worldraft]

Well I tried but my equipment could not heat the material enought

[miguelgarbutt]

Very useful post! Thanks!

[Panther]

I have done several LiPos without that hassle. I scrape the tab with a sharp blade and use ordinary Rosin core solder with a 12 Volt 'instant' iron. Highly unlikely that any oxidation is going to form in a few seconds. I have never had a joint fail.