Best way to clean oxidized Aluminum before welding

Are any of those aluminum cleaners suitable for use in cleaning aluminum before Tig welding?

Seems like sanding oxidixed aluminum gets some of the grunge but grinds the rest of the oxide into the surface of the metal - is it better to try and etch it off with acid first or on the other hand are there Al cleaners that work or fluxes designed to help with getting the bead to wet when metal is oxidized on the surface?

I've seen more experienced Tig welders welding some pretty crummy looking aluminum (old propellors etc.) so there must be some tricks to it.

Apparently more electrode positive time (indicated as lower "% negative balance" on Miller machines) accelerates the Ar ions so they bombard and clean the surface - any other tips?

We used to clean telescope mirror plates under low pressure argon with high voltage so that we could aluminize them - same principle (the low pressure allows the Ar to accelerate even more before they get slowed down bumping into another gas molecule)

Maybe I should be giving my old aluminum pieces that need to be welded a bath in Ar with a few kV applied to really clean them.

Graham P

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Graham P
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When you clean aluminum you need to do different things to remove the oxide from removing grease or oil. I think Ernie recommends using acetone to remove the grease. Might be the best choice as it will evaporate. But any good degreaser ought to work. Brake clean might be a good choice too. Anyway you need to degrease before sanding to remove the oxide. And you probably ought to clean again after sanding to be sure you got any loose grit off the aluminum.

A good test for cleaning is a water break test. Water should run off in a sheet wetting the entire area.


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Years ago when I was a Aircraft welder in the Navy we would take an oxy-acetylene torch and with a highly carboizing flame and blacken the aluminum then adjust to a neutral flame and heat till the carbon black was gone then clean with a stainless steel wire brush... seemed to work well...


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