General welding questions that dont fit in TIG, MIG, Stick, or Certification etc.
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Wildwelder96
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    Fri Apr 03, 2020 10:51 pm

Do you clean aluminum with acetone before you wire brush the metal or after? Is it okay to use a flapper wheel instead of a wire brush?
BugHunter
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    Sun Apr 19, 2020 12:54 pm

Aluminum will gall and melt if you use high speed abrasives. At that point, you've got dirt melted into the part. Wouldn't be my first choice. You may get away with it being very careful, but it's not worth it.

A wire brush wet works well. You can use regular non-ammonia cleaners too. It doesn't have to be petroleum based. Just be sure to rinse well after you're done. But dirt loves to embed in the surface of aluminum, so I avoid consumable abrasives when possible. If you're forced to do it because you have a lot of area to clean, and little time to clean it, just use very little pressure and generate as little heat as you can. Slow down if you have a variable speed tool.

I also avoid acetone but I know almost everyone else uses it. I'd say use it after brushing if you're doing both. That should be the last step imo.
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Both. To remove any surface crud that is already there, before the stripping of the oxide layer. And then after for good measure to wipe off any oxide particles left in the vicinity from the wire brushing.
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dgapilot
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    Wed Jul 26, 2017 7:00 pm

Don’t forget, whatever you use to remove the oxide layer, be it stainless brush or abrasive, be sure it has never been used on carbon steel before. Keep one set of tools and abrasives for steel, one for stainless and one for aluminum and NEVER mix them!


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tweake
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BugHunter wrote:Aluminum will gall and melt if you use high speed abrasives. At that point, you've got dirt melted into the part. Wouldn't be my first choice. You may get away with it being very careful, but it's not worth it.
you can lube the abrasive with wax ie bees wax.
tho a better way is to use a variable speed grinder and slow it right down so you don't get that galling and melting.
however you do get fine aluminium swarf which you need to clean up otherwise, if left on your part, its gets sucked into your tig torch.
tweak it until it breaks
Spartan
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I clean it both before and after brushing. No sense in brushing contaminates right into the material from the start. Brush lightly in only one direction with a fresh brush (nice sharp bristles) for several strokes, and be sure to blow away the oxide dust that you will see accumulating every few strokes. You don't want the brush to just jam those oxides right back into the material.

I will use flappers or wire wheels only when the AL is quite dirty to begin with...like if its been left outside for awhile. It's not ideal as others have mentioned, but when the AL is already particularly dirty, then it can still make things easier. The lesser of two evils, I suppose. I never take any flappers or wheels to AL that is fresh.
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NEVER use a power tool to clean aluminum for TIG welding. All you end up doing is driving contaminants deeper into the metal. Brush by hand only. I do as Oscar said. Before and after, just to be safe. There are millions of stories on this board an others about people trying to clean aluminum with an angle grinder and a wire wheel or flapper disk and just mucking things up horribly.
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