Can it be done?

[Semtex]

Very simple question looking for a very simple answer.

Is it possible to weld (arc or mig) aluminium.

Basically there is a garage door just down the foad from me that is "free to take"

It is a decent size to practice on (although I don't no how deep the metal is) but it is made of aluminum by the looks of it.

Is it worth grabbing as a practice piece (bearing in mind I've only got access to an arc at the moment but am looking to upgrade to a mig) or would it be a waste of time and effort dragging it up the hill?

 

[Wozzaaah]

It's more likely to be galvanised steel than aluminium but to answer your question, yes, aluminium can be mig welded very successfully. A couple of minor changes to the machine, some pure argon and plenty of practice is pretty much all it takes.
Regarding arc welding alu, you can buy aluminium electrodes but I don't think many people bother with them, mig or tig all the way.

 

[shenion]

Can be done with arc but only on heavy stuff and most consider it as a "last resort".

MIG will work with pure argon gas. Takes a lot of practice and works best on a machine with a smooth wire feeder. A spool gun is optimal.

 

[Semtex]

It's more likely to be galvanised steel than aluminium but to answer your question, yes, aluminium can be mig welded very successfully. A couple of minor changes to the machine, some pure argon and plenty of practice is pretty much all it takes.
Regarding arc welding alu, you can buy aluminium electrodes but I don't think many people bother with them, mig or tig all the way.

If it is Galvanised steel as you say, would you say it is worth grabbing then for arc practice? Now I've taken advice and got a flap pad for the anglegrinder.

I don't know how long it will be before I get a mig

 

[madkayaker]

it would probably be a bit thin by the time you had taken the galv off and not very good to practice on really as galved steel is nasty to weld and harder than clean steel but if its free then try it! if its ali scrap it and get some cash for weighting it in

 

[PTvor]

You've got to be very careful welding galvanised steel.

The zinc evaporates with the heat of the arc and if you breathe the fumes in you get an illness called fume fever, which is supposed to be like a dose of flu and leave no permanent effects, but it's best avoided.

Also the zinc partly mixes with the weld metal and the welds may not be all that strong.

So, you either have to grind the zinc off as far as it's going to be affected by the heat or dissolve it off with hydrochloric acid (spirits of salt). I've also seen rods made by Selectarc I think, which are specially for galvanised steel, in which case you'd need very good fume extraction to get the fumes well away from you even in the open.

What you certainly shouldn't do is simply go ahead and weld it as if it was an ordinary piece of mild steel without thinking about it very much.

 

[Semtex]

Thanks for the replies guys............I think I will pass on that particular free offer!!!!

 

[PTvor]

If someone offered you say, a couple of 6ft lengths of galvanised angle, it would be well worth having and putting by against having a job to do with it. You could store it anywhere and for a job, you might be able to bolt it, or if you had to weld it you might only have to get rid of the zinc at the ends, which is dead easy with acid, or even a grinder.

But to use the galvanised angle for practice, where you are deliberately laying down a lot of weld, would be a different proposition.

Thin galvanised sheet is worth having. It's no good for welding, but you can pop rivet it.

 

[Hitch]

Have it and weigh it in, might get a pint for it
I wouldn't have it for practice, probably electro galv, and at that thin, never worth messing about with.

 

[grim_d]

I would say thin galvanised sheet is worth having for mig welding (I know this is in the ARC section ), I have been harvesting 1mm galv steel for my project car from a bunch of mk2 mr2 panels I couldn't get shot of, a quick buzz over with a flap disc gets rid of the galv no problem.

Although I have no idea how thick garage door material is, anything less than 1mm probably wouldn't be worth it as by the time you have buzzed over both sides to get rid of the galv you will have probably lost 0.2mm or more.

 

[^neo^]

I'd do what Hitch says, take it to the scrappy and swap it for a few bits of plate to practice on!

 

[Semtex]

If I had any transport to do that, I probably would. ATM I don't

 

[Wozzaaah]

I doubt you'll find it's as thick as 1mm so really not worth the bother.

 

[asmeix6g]

well seeing as MIG can only be used on aluminium and its alloys, id have a good guess and say yes you can weld an aluminium door with it keep the torch almost 90 degrees to the work piece or youll find your just spraying spatter across your workshop and if your not careful you'll lift your screen to see many items around you on fire! let us know how you get on