Can I weld aluminum with a mig welder if I have flux core wire?

My parents got me and my younger brother a mig welder for Christmas they also got flux core wire because gas is expensive. But my brother keeps saying that we cant weld aluminum with it I have heard of aluminium flux core wire but he still says it wont work. Dose the aluminum flux core wire work any good or is there something else we need to get?

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iceng2 years ago

Aluminum is welded with AC current and a covering gas to prevent Al2O3 oxidation which hurts the weld strength.

If your flux core can displace the oxygen around your weld give it a try. It will only hurt the scrap aluminum.

Dalen Brewer (author)  iceng2 years ago

Could it hurt the welder at all?

"It will only hurt the scrap aluminum."

The welder does not care what it is welding.

But for the solfter aluminium wire you might have to adjust to feeder.

The only flux core wire for aluminium I have seen is for soldering, not for welding though.

If you want to try the welding get a roll of aluminium welding wire and a disposable Argon gas bottle, the small ones are quite cheap.

You will need a fair amount of practice round to get the settings on the welder correct and to create a good weld.

IF you can get cores wire for aluminium then you can use it. I haven't seen any though and I endorse everything said above. Despite efforts to solder aluminium several times I always end up using a mechanical attachment - pop rivets work well.

Welding aluminium can be a pain in the butt if you don't have the right welder and use Argon gas.

For small repairs I actually prefer soldering the aluminium.

Not recommended for structual work or bigger repairs, but good for cracks, holes and small things.

In any case clean tools made from stainless steel are a must have - I strongly recommend to only use dedicated tools that will get no use on other materials!

Just a quickie for soldering:

You need;

Sharp knife (stainless steel)

Stainless stell wire brush

Stainless steel scraping pin - I use a thick stainless steel wire, one side ground flat like a screwdriver, the other like a needle

Plumbing solder - the thick kind with no flux in

Acetone to remove any grease and oil before starting

(small parts I dump into a solution of sodium hydroxide to remove the oxide layer)

Blow torch or big soldering iron for smaller parts

How to;

Clean the aluminium from dirt and grease.

Scrape the soldering area with the knife to remove the oxide and some material so it can be replaced by the solder.

Use the wire brush after to smooth the surface a bit or to clean hard to reach areas - wherever you need solder the alu must be free of the oxide layer.

Fix the two parts together so they can not move and try to make sure there is no gap between them, this helps a lot.

Heat the aluminium, either with the soldering iron or blow torch from the other side (you don't want the flame on the area to solder until you actually have some solder sticking to it.).

Once the parts reach a good heat (check if the solder starts melting on the alu) use the wire brush or scraper to keep the oxide layer from building - this is an ongoing process.

Scratch the solder over the aluminium, you want to the heat so the solder needs a moment to get soft, you literally scratch the solder off the solder stick onto the alu.

If the solder won't stick in some areas use the scraper and the solder around the area to scratch through the oxide, you will see it is correct when the solder starts to form a "film" on the aluminium insted of just sitting on top of it.

Once it looks like you covered the entire alu surface (where you need it) with a thin layer of solder it is time to fill the crack, simply add more solder by scraping it in.

It might be necessary to use the scraper or wire brush a few times until you really get the solder where you need it to stick.

Add enough solder it goes slightly over the surrounding aluminium.

If you think it looks good leave it otherwise cut the excess solder off or file it down, once polished you won't even see the repair area.

When you say plumbing solder, your talking standard lead (or lead free equivalent) that's used on copper and steel etc?

Flux hurts the process does it?

Impressive