Soldering to aluminum

[cellularmitosis]

Just wanted to report that I took a risk on ebay and was pleasantly surprised.

I searched for a flux to be able to solder aluminum, and came across this obscure looking Russian product: F61A "highly active" flux for soldering aluminum.

This stuff appears to do the job.  I wiped some onto aluminum foil using a Qtip, and was then able to solder a wire to it.  Pulling hard on the wire tore the foil before it broke the solder joint, so it appears to be a good joint.

http://m.ebay.com/itm/271204471686

[c4757p]

Be warned, that stuff probably won't treat your iron tip well. Use a shit one.

[T3sl4co1l]

Make sure not to breathe the fumes, or even get it on your skin.  Those fluxes are usually fluoride based.  As in ammonium bifluoride, which is "only" half hydrogen fluoride.  (I don't suppose you can find the Russian equivalent of an MSDS on that stuff...)  If you want a scary time next Halloween, dig out some case reports of HF poisoning.

Tim

[Co6aka]

Appears to be homemade. A legit RU or Eastern-EU company would publicize itself on its products to hopefully promote sales. There's a company "Teknochim" in Bulgaria, but text on the bottle is Russian. The eBay item you linked to has a different photo; alleged manufacturer "Spets Chimiya STX" but after a couple of minutes of searching I haven't found anything. Maybe ask the RU board members to see what they can find out.

Update: Here's what looks more like a legit one, with a Ryazan phone number on it, but it's past the expiration date: http://www.ebay.com/itm/281209501746

[cellularmitosis]

Whoa, thanks for the warnings, guys, I had no idea.

Googling for ammonium biflouride brings up an MSDS for Superioflux for stainless steel: http://www.superiorflux.com/msds/71_msds.pdf

[XynxNet]

Read this article about soldering aluminium a few years back. Maybe it's helpful.

In English via google translate
http://translate.google.de/translate?sl=de&tl=en&js=n&prev=_t&hl=de&ie=UTF-8&u=http%3A%2F%2Fwww.heise.de%2Fhardware-hacks%2Fartikel%2FRexin-Universal-Lote-1744235.html

In German
http://www.heise.de/hardware-hacks/artikel/Rexin-Universal-Lote-1744235.html

[Macbeth]

Thank you! I have always had a problem soldering to my Bacofoil hat designs. Crocodile clips just chewed through them. Now I can finally ground my brain to a gas pipe for proper earth and stop the Thetans from Xenu reading and infiltrating my mind! Has anybody brought this to the attention of Tom Cruise?

[Neverther]

I find this kinda funny as we used to repair soviet era devices and the we always joked about the wires being aluminium as the most common job was repairing the hardened and cracked powerleads.

[ablacon64]

In Brazil some guys solder aluminum using paraffin as flux:

That soldering iron is called "Capetão" (something like "big devil") around here.

[IanB]

I've tried a few experiments soldering aluminium, especially excluding oxygen by soldering under oil or paraffin. However in all cases it has completely ruined the tip of my iron. It's as if the aluminium affects the plating on the tip and stops the solder sticking to it :-(

So as others have said, don't try this with a good soldering tip!

[Macbeth]

The only real "soldering" of aluminium I would attempt is using a TIG welder with Argon gas and proper filler rod.

[SeanB]

I saw some OHL car audio wiring last week that purported to be 0 gauge, but the reel was way too light for the reported 30m of copper cable, and on looking at the cut end all I saw was silver with a copper coat. This was a roll of copper coated aluminium, not exactly a thing I would try to solder. Might work with a crimp, but still not going to be a thing I would try to have 300A flowing through.

[T3sl4co1l]

Funny... I would think soldered would be better, since the solder (assuming nice soft leaded solder) allows compliance against thermal expansion, while the crimp won't be much better than a crimp on bare aluminum.

Tim

[JackOfVA]

I've used a couple of simple ways to solder aluminum to aluminum.

One is a zinc rod - you see these at hamfests for those of us who are amateur radio operators - looks like a standard welding rod without flux, but its 98% zinc. This will let you solder two aluminum cans together with a propane torch. These are relatively cheap and I've had decent success with them but it takes a bit of practice to get it right. Flux is not needed.

The second is with 60/40 tin/zinc solder and special flux - not recommended for electronics, though. I've used this to solder thin aluminum shields together with a propane torch and it also worked reasonably well.

[wilheldp]

This was a roll of copper coated aluminium,

What an astonishingly stupid thing to exist.  Copper + aluminum + water = galvanic corrosion.  Corrosion = higher resistance = heat.  This is why Cu-Al breakers and wire nuts keep the two materials from coming in direct contact with each other.

Are you sure it wasn't copper coated steel or some other material?

[SeanB]

Too light and flexible for steel. Just another roll of OHL junk.

[peter.mitchell]

copper coated alu is pretty common in chinese stuff, alu is the next best thing to copper; it is about 60% as good of a conductor, buy is significantly lighter, cheaper and more corrosion resistant. with copper coated alu you don't really have to worry about galvanic corrosion along the length of the conductor as the copper covers the outside, only at the terminations are they both apparent.

I am a pretty proficient TIG welder, i'm able to do autobody no issues and have "shown off" my skills many a time welding soda cans together. That said, I would never TIG weld anything electronics related. Aside from the process being pretty dangerous for electronics components, you have relatively little control and accuracy compared to an iron.  It just doesn't seem right. That said, previously I have tig welded lithium pouch cell terminals because a spot welder was unavailable, I was hesitant at first but as the material is so thin is it VERY quick and you don't heat the cell much at all.

[wilheldp]

copper coated alu is pretty common in chinese stuff, alu is the next best thing to copper; it is about 60% as good of a conductor, buy is significantly lighter, cheaper and more corrosion resistant. with copper coated alu you don't really have to worry about galvanic corrosion along the length of the conductor as the copper covers the outside, only at the terminations are they both apparent.

Yeah, I thought about it after I posted and figured out that if the material was bonded properly, it shouldn't be as big of an issue because no current should be flowing through the boundary between the dissimilar metals (which caused the heat after the corrosion).  I still think it's a bad idea, though.

[nctnico]

Appears to be homemade. A legit RU or Eastern-EU company would publicize itself on its products to hopefully promote sales. There's a company "Teknochim" in Bulgaria, but text on the bottle is Russian. The eBay item you linked to has a

AFAIK Russian (-ish) is the official language in Bulgaria.

[nukie]

If you are desperate, spot welding or ultrasonic soldering will do but both needs special equipment.

[calexanian]

I just install an eyelet or use a screw as a terminal. Also you could use some of that allumalloy and put some brass sticking out and solder to that.

[Dielectric]

I didn't realize it was so hard to solder to aluminum!  I had good luck soldering through a puddle of 3-in-1 oil.  The trick is to puddle the oil then scrape the Al in order to expose some unoxidized metal.  Its like shielding gas that doesn't blow away.  Used tin/lead solder and yes, it smoked just as much as you'd expect.

[scientist]

Compared to soldering to lithium, well, aluminium is easy.

[Psi]

Compared to soldering to lithium, well, aluminium is easy.

lol

Or soldering one block of U235 to another one

[SeanB]

Compared to soldering to lithium, well, aluminium is easy.

lol

Or soldering one block of U235 to another one

That is actually quite easy, just use a shaped charge and explosive deformation. Problem is keeping it together though once it is all joined up, it really wants to be extremely unhappy.