Aluminium welding.

I’m not a welder, but it’s a skill I’d like to have. Small checker plate door with a fold on each edge resulting in a metre butt at each corner about 25mm long, see picture.
Plan to weld the corners with my small Clarke 100amp unit.
Will practice lots before on scrap pieces. Should I approach it as a series of tack welds joined up? Or something else? Any advice welcome.

Spool gun or tig?

Mig. No separate gun, just the machine feed.

My advice, as a welding engineer, is to find someone local to you fluent and current with welding Ali - having years of experience myself , I would not attempt it with a clarke MIG set.

IMHO, that is a job for TIG - there is bound to be someone local who does this for a living, and would exchange the job for a few beers ...

If you feel the need to have a go, then I wish you luck, largely because the Ali wire will likely be a Complete PITA in that welder's wire feed mechanism - the wire is very soft - which is why spool guns are used ...

Also, you will need to use either Argon or Helium for shielding ( or maybe ArHe mix ) - Ar CO2 mix will not work.

You might have better luck with some sort of silicon bronze brazing technique - I think there are vids on the tube for this. ( not something I have experience of on Ali ).

Good Luck

Cheers, I’ll have a go. If it’s a failure over to a pro. That’s a challenge at the mo with lockdown and all.

retneprac said:

Cheers, I’ll have a go. If it’s a failure over to a pro. That’s a challenge at the mo with lockdown and all.

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It won’t work. You need to weld Aluminium on AC. Your MIG will be DC. Worse still is a TIG set is constant current, MIG sets are constant voltage. Try on scrap first, but it’s a non starter.

You can get “welding rods” that you use a map torch to melt. These work reasonably well and are relatively cheap for doing small localised repairs. Other than that, ring round a few metalworking places. See if one of their guys will come to you and do the job.

As per other replies it won't work, don't waste your time and money even trying, spend less pennies getting it done by somene already rigged up to do it.

What’s the aluminium spool for Migs intended use?

Yeah good luck with that.

AC tig is best for this, and use argon only

retneprac said:

What’s the aluminium spool for Migs intended use?

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For MIG welding, but unless your MIG has an AC / DC setting, there's no point in messing with it. Ali welding requires AC, which is often not something that the average MIG can do, as steel requires DC.

Get it done by a professional who's set up to weld ali with TIG, and save yourself the hassle.

Will it do for a Landy camper locker side door? Practice piece, roughly filed up, rattle can Matt black to see how it could look! Not really a structural joint, more gap filling!

retneprac said:

Mig. No separate gun, just the machine feed.

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Hell thats adventurous. You'll be practicing for months unless you are some kind of undiscovered god of the aluminium welding world.
I've tried many times and found without exception that you need training or better still a proper welder to do it.
If you manage to work how to do you must publish it here for the rest of us.

Think that might be a pic of his practice attempt in the post before yours......

if anyone doesn't know what a spool-gun is.



and as I'm a hoarder....



have 240v and 440v Camarc sets

but I've no argon

Rich.

retneprac said:

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Fair play if that was done with DC MIG, but I wouldn’t trust it for anything.

mick 1986 said:

Fair play if that was done with DC MIG, but I wouldn’t trust it for anything.

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Yes it is the practice piece. It’s just a small hatch door. 220x270mm ish. Folded sides so it has a bit integrity already. Hinges and a lock next.

retneprac said:

What’s the aluminium spool for Migs intended use?

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In simple terms, it is to keep the run of alloy wire as short as possible, in a std mig it will bunch up and jam pretty much non stop.

I bought some of them alloy cold welding rods, and have to say utter dog shti, but I welded/glued/smeared a cracked two stroke engine block up, I did have to smear it with sikaflex afterwards to stem the water leaks, but mechanically it held.

I quite like the the Durafix rods. Having said that I’ve used cheaper ones and they are junk. Oh and map gas is a must. Ally wicks away heat that fast you can struggle to keep even 1mm sheet hot enough to melt along a joint. It does bead however so I use it more as a filler then shape it when cold.

it would be ideal for those corners.

I've had mixed success with the ally "brazing" rods. A couple of great successes and the same number of failures with no obvious pattern to why. I have also tried spot welding ally, with and without steel packers, and about 1 in 10 is a good strong weld, the rest are rubbish and again, no obvious reason why. I gave up on the ally spot welding because there was a 50/50 chance the ally would weld to the packer or the electrode and I'd spend the next 10 mins filing it all back to shape. I used to get all fabrocations welded up many years ago. A place with all the right paperwork always made a mess of it, but one guy in a shed was a magician with it. He was slow and had a massive old welder, I think he always got a lot more heat into it.