MIG welding Aluminium ??

[Smallfry]

Will start this off by saying that I have never tried welding aluminium before, OR watched it being done.

For my latest hare brained automotive scheme, I will need to weld a gearbox bellhousing, and possibly a sump (oil pan) both cast in aluminum of an unknown type. Thicknesses are something like 6 to 10mm. Not cut them yet so not sure.

I have a Migatronic 231 that I bought new 15 odd years ago, but hardly used it. It will give up to 200 British amps apparently, and has a Euro connector. I gather I will be better off with a spool gun anyway, even though access is not a problem, as I can do this on a bench. I am aware I will need pure Argon, so will need another cylinder. I know TIG is the favoured option, but at my age, I do not want to spend lots on new equipment and the time it takes to learn how to use it. I also don't have space !

From what I can gather, it is quite difficult compared to steel and the welds are likely to look "sub optimal", but thats not really a problem, as they can be cleaned up.

So really, I am asking, will the machine do it ? Will my laughable welds be strong enough ? The bellhousing especially need aligning properly, but I have a heavy jig for this. What about distortion ? Will this be a potential problem ?

Or will I realistically be better off getting someone else to do it ?

 

[hotponyshoes]

You'll struggle to do 10mm with a 200a machine. Migh work if you can pre-heat the material (along with more distortion problems)

You'll also need Alloy wire, feed rollers, teflon liner and tips. Ideal the shortest torch you can find.
If the welder accepts a spool gun that's probably the cheapest way to set up for alloy.
Get a stainless wire brush as well as clean prep is important.

Getting it set up, feeding and running right can be a learning curve but the actual welding itself is not hard. If you can already mig weld you'll pick it up after a few practice runs.

 

[minimutly]

I bought a spool gun from someone on here. My little BOC is too small to try, but I had a single/three phase machine here for repair. At the amps I needed to weld 1/4 inch it was taking out a 20A breaker occasionally.
8 to 10mm? I would say you need a 3 phase mig.... Actually a 2 phase 415V, but you know what I mean

 

[Smallfry]

You'll struggle to do 10mm with a 200a machine. Migh work if you can pre-heat the material (along with more distortion problems)

You'll also need Alloy wire, feed rollers, teflon liner and tips. Ideal the shortest torch you can find.
If the welder accepts a spool gun that's probably the cheapest way to set up for alloy.
Get a stainless wire brush as well as clean prep is important.

Getting it set up, feeding and running right can be a learning curve but the actual welding itself is not hard. If you can already mig weld you'll pick it up after a few practice runs.

I was thinking of a spool gun in any case, but I didn't know it was so power hungry !

I don't want to buy the necessary though, and find it doesn't work. I have done loads of steel welding, so thats not a problem, but what about spool gun and gasless wire ? Is it feasible to tack it, and then take it to someone with TIG ?

I presume that even with TIG, distortion is going to be a problem ? If it were here, I could bolt them both down to an old engine block if that would help.

 

[minimutly]

Gasless Ali mig wire? didn't know that was a thing. Spool guns are cheap enough - try it and see with the mig you have. I though I'd need a piggy back speed controller, in the end I just spliced into the existing feed wire output, worked fine. A propane torch might be a good idea for some preheat?

 

[Smallfry]

Gasless Ali mig wire? didn't know that was a thing. Spool guns are cheap enough - try it and see with the mig you have. I though I'd need a piggy back speed controller, in the end I just spliced into the existing feed wire output, worked fine. A propane torch might be a good idea for some preheat?

I don't know if gasless wire is a thing either. Not looked it up yet. Just guessing

Preheat ? I have got a propane nozzle like a Saturn V rocket, but I still could not get enough heat in a Rover V8 cylinder block for Lumiweld to work.

 

[Munkul]

You want around 250 amps and a big preheat to repair a sump that thick. And that's assuming it's even weldable alloy... some sump castings have too much zinc in them and you get porous welds. Or sometimes the casting itself is porous and you have a load of trapped oil to burn out of the material with the TIG torch before it will even hold a weld.

This is a TIG job I'm afraid.

 

[Smallfry]

I thought it probably would be.

Maybe for the best anyway as it would look better and not leak !

The easier option I guess, is to chop the steel crossmember that is in the way. But TBH I would rather not do that.