Soldering Aluminium with a Hand Iron

[@rt]

Hi
I’m basically here to gauge whether or not this is a thing.



Tell me how it was done, and I’ll tell you if you were right.

[bd139]

You can solder aluminium fine. My father did it with some wet and dry, a bog standard Weller TCP, a can of pepsi as flux (stinks but works) and standard 60/40.

[helius]

If you'd rather not use soft drinks for soldering (just one Pepsi!), the active ingredient is available as orthophosphoric acid. It also enables soldering to stainless steel.

[@rt]

If it’s a commonly known thing, fine. Basically what I’m here to find out.
It would make me wonder though, why every YT video about soldering aluminium involves a blow torch.

Every attempt I have made failed. I have tried when projects with lots of chips and multiple boards have become structures,
until I was told a trick using a hand iron, leaded solder, and one more household material that is needed, but not consumed.

[bd139]

I think only an idiot would solder aluminium with a blow torch. They are very hard to control temperature of and aluminium disappears around 660oC.  If you do manage to solder it, it will no doubt change the properties of the aluminium and weaken it or make it brittle. So the solder joint might be there but one tug and the thing you soldered will fall off.

If you'd rather not use soft drinks for soldering (just one Pepsi!), the active ingredient is available as orthophosphoric acid. It also enables soldering to stainless steel.

Yes use the proper stuff if you can. The Pepsi stank terribly. It's not good for the tip either.

[Gregg]

I have made good joints with Allstate 509 http://www.esabna.com/us/en/products/index.cfm?fuseaction=home.product&productCode=1088
Unfortunately it contains cadmium which may not be suitable for some situations, but it really works with the recommended flux.  It even seals refrigeration leaks in aluminum components and bonds copper to aluminum reliably.  I have a tip for my Weller D550 soldering gun that is tinned with this stuff and would have no trouble with making a joint as shown by OP.  On larger aluminum parts that pull the heat away, a torch works well but the flame needs to be kept away from the joint area and let the aluminum conduct the heat to the joint.  A torch could be used to make a joint as shown by heating the aluminum strip from the back side. 

[coppercone2]

I dislike soldering or brazing aluminum. Compared to copper or even steel they are shitty in all regards. Welding aluminum is better but its still the worst of all the conventional metal processes.

Get the special al solder and al flux to make your life easier but keep in mind it still kind of sucks.

Soldering sanded aluminum is not the worst though. Torch brazing aluminum is a exersize is fustration. Of all the welding processes i tried even when i almost had no idea what i was doing you got some kind of joint that was at least partially functional. With the cheap al brazing rods and flux etc i just got pissed off. It just does not work right.

The benzomatic home depot aluminum brazing rod actually worked better then welding store stuff. Maybe my alloys were wrong, but holy shit! You might turn into the hulk doing this.

[magic]

If you'd rather not use soft drinks for soldering (just one Pepsi!), the active ingredient is available as orthophosphoric acid. It also enables soldering to stainless steel.

I was able to solder a broken thermocouple with it too, good stuff. Fosol for those in Poland
Didn't know it helps with alu, I actually ordered a dedicated flux for that just a few days ago.

The seller of that flux also says that lead-free is supposed to be better than 60/40. Not sure why would it be but that's what he said.

[rhodges]

Many years ago, I wanted to solder copper to an aluminum rod. After failing in so many ways, I finally had success using a zinc penny as my "solder".

[SiliconWizard]

I'd use some Arax cored solder wire for that. But aluminum is a bitch.

And wear protective glasses. This thing splashes all over while reflowing.

[@rt]

That pretty much answers my question then.
Other than the first reply, it’s all about commercial products, acid, etc.

What I said was:
"until I was told a trick using a hand iron, leaded solder, and one more household material that is needed, but not consumed.”

Jut gauging whether or not it’s worth a YouTube video. I think it is.

[@rt]

Ps. The first reply might work, but nope. No mess, no stink, no splash, no inconvenience.

The material I didn’t mention is also non toxic and can be (and is often) ingested.

[IanB]

You can solder aluminium under a layer of mineral oil. You need to scrape the surface of the aluminium under the oil to remove the oxide layer, and then solder it quickly before the oxide layer re-forms. It totally ruins tips though. Best to use one that you don't care about.

[@rt]

You took your time Ian!

I used Vaseline, which when heated, I guess is something like petroleum based oil.
That was simply because I had Vaseline, but not Mineral Oil.

[magic]

That pretty much answers my question then.
Other than the first reply, it’s all about commercial products, acid, etc.

What I said was:
"until I was told a trick using a hand iron, leaded solder, and one more household material that is needed, but not consumed.”

And what we said is how to do it properly without wasting your time on scrapping the oxide off the surface and messing with some disgusting sticky crap
I knew about that trick long ago, but meh.

And the first reply is about a commercial product and an acid too.

[@rt]

If that’s the case, they are answers to a question that wasn’t asked.

As a hobbyist looking at a piece of scrap aluminium that will fit somewhere better than some other piece of scrap copper,
I’m not going to buy a specialised product (which Pepsi Cola also isn’t) to do a simple job that is being done right now.