Soldering 'Bacofoil'

[ITAM805]

My first reaction was, "it cant be done"! Well it seems it's possible although when I tried it, my 25W iron melted the foil before I could tin it! Might be useful anyhow.

Here's how - apparently...

[vinrads]

Very interesting must try it. Mick.

I just use plenty of solder, the flux works like the oil, but why 4 odd minutes of video for a sentence or two?

[stevehertz]

Why indeed? Well, it's an AMERICAN video. They just seem to love making videos as long as possible in order to make a simple point. I dunno, go figure.. I watched a similar video about making a longer coffee when using a Nespresso machine. Basically you just needed to press the machine button twice instead of once, but the guy making the video makes a real meal of it..

[Steve_Bell]

Once upon a time you could buy multicore "aluminium solder" - for soldering aluminium, rather than made of aluminium. I think it had a very high lead content and a quite corrosive flux that you had to wash off.

[Radio Wrangler]

Ersin "Alusol"

David

[TonyDuell]

I have soldered to (small pieces) of sheet aluminium using the 'under oil' method. I've not downloaded the video so I can't be sure it's the same, but what I did was to clean the aluminium surface, put a drop of machine oil on it, then scrape the aluminium under the oil with the (Weller TCP No 8) soldering iron bit and tin that part with normal rosin-core solder.

Some of the special aluminium solders contained quite high proportions of cadmium and were quite unpleasant to work with. I would not want to use them without some form of fume extraction.

[Peter.N.]

I used to solder onto the back of radiospares preset pots by just keeping on scraping the aluminium with the soldering iron bit and frequently applying solder, it was probably the flux that was preventing oxidisation and allowed eventual adhesion

Peter.

[Radio Wrangler]

I was walking around the Aero 2009 exhibition in Friedrichshaven ad there were at least two stalls touting filler metal for repairing aluminium castings and were demonstrating using a fairly ordinary DIY gas canister blowlamp. There was a special flux and a filler rod. It wet the aluminium and flowed quite nicely, though I'm seriously doubtful about the strength compared to a proper weld.

I wondered about it for making radio chassis etc.

I'm just worried that these people were demonstrating the stuff at Europe's largest AVIATION exhibition.

Gulp!

David

[richrussell]

There are quite a few products for brazing aluminium, usually consisting of some alloy filler rod and a flux. Mig welding sets have progressed now with electronics good enough to manage the arc so that you can actually Mig weld aluminium (with aluminium filler wire obviously). It's no longer the domain of Tig or micro-gas welding.

[Radio Wrangler]

I've used MIG on aluminium. It works quite well, though the constrained relationship between heat input and filler input isn't ideal. I used to weld aluminium with oxy-acetylene and a tallow candle for flux, so anything's easier than that!

Nowadays I have a very good quality TIG machine and welding aluminium is easy. The antennae at home are on a stub mast on the gable end - the mast and supporting brackets welded out of thick-wall aluminium scaffolding tube.

I just hope no-one at Aero 2009 used any of that low melting point stuff on anything critical.

David

[Andrew2]

I've successfully soldered to aluminium cooking foil many times using conventional solder plus some 'powerflow' plumbers' flux. I just apply a small dab of flux to the foil and then 'rub' the iron bit on the foil while applying solder (ordinary savbit). Works every time and the joint is a proper one ie not just a blob stuck on.
When I was an apprentice, I watched one of the old hands soldering some ally sheet with a big, hot iron, plenty of flux and using a wire brush to keep the surfaces clean. It worked a treat.

[Karen O]

I soldered to some aluminium once not knowing it was aluminium, though I should have guessed from the trouble I was having. I swear it contaminated my bit because it was never quite the same again. I replaced my bit soon after because it made normal soldering a pain.

[Radio Wrangler]

One technique is to use the soldering iron to create a pool of molten solder and to move a scraper around within the pool, scraping the oxide off of the aluminium and pushing the slag out of the pool. Doing this by rubbing with the bit itself can contaminate the bit.

David

[peter_scott]

I've used HTS2000 to braze aluminium and the joint is so strong that you can hit it with a hammer and it will not part but rather the original alloy will fracture. That said the HTS also machines easily. I have no connection with this company but am impressed by their product.
Here's an alloy pulley with a missing chunk. The HTS can be easily puddled to form a replacement for the missing part and machined to shape.

Peter

[ITAM805]

Originally Posted by Karen O

I soldered to some aluminium once not knowing it was aluminium, though I should have guessed from the trouble I was having. I swear it contaminated my bit because it was never quite the same again. I replaced my bit soon after because it made normal soldering a pain.

I think you may be on to something Karen, my genuine 8 month old Antex bit seems knackered since I tried soldering tinfoil - or is coincidence? Is there something in aluminium that contaminates nickel/iron? Anyway I fitted a new tip today and all is good again.

Perhaps the thread should be changed to 'The Dangers of Soldering 'Bacofoil'