Best way to clean old aluminum for TIG

[jtybt]

I have some old (1/4") diamond plate aluminum that has lots of pitting and needs clean-up in order to make a foot pedal housing for a foot pedal project for the TIG.

I don't think wire wheel would clean the pits. Is there a mild acid bath that would work?

[acourtjester]

Lobor wise it may be better to sell it for scrape and look for some cleaner stuff. Some scrape yards let you look around you may be able to pick up some good stuff.
Just a thought!!

[bigjoeinkg]

The scrap yard here will let you look around. Depending on how much you want they give it to you or sell it to you for $0.50/lb the last time I was there. I also check out fab shops for their scrap. Sometimes you get lucky with practice / small project material.

[jtybt]

Yeah, I guess I could go to a scrap yard. I been doing that for some years. It's just that I've had this platform from the back of a truck just laying around. I might try laying some beads for practice on a bit of it and see what it takes to clean it to weld.

[Timberwolf]

I'd use it. Just wire brush and or grinding wheel and go at it. what do you have to lose?

[acourtjester]

You guy are lucky the yards around here just say we don't do retail so you can't go in to look. They are just set up to buy scrape end of story.

[jtybt]

Oh yeah, I went looking for 3/8-1/2" round SS to make rod holders. Found 3/8 sq SS so I got maybe 15'. It's just been laying around so just for giggles I tried it as a guide for the PP50. It 'rode' on it perfectly. Set it 5/16 from the intended cut and it just zips right through...and being square it clamps easy. I welded a 90* piece so I can clamp it away from the cut. Neat stuff.

[Tritium]

You guy are lucky the yards around here just say we don't do retail so you can't go in to look. They are just set up to buy scrape end of story.

Same problem here Tom. Nothing leaves the yard that comes in through the gates. It drives me crazy to see a huge pile of stainless steel I could use to build my ethanol plant but can't buy, beg, borrow or steel (pun intended).

Thurmond

[jtybt]

Oh heck, I've seen 50 gal SS drums that would make beautiful BBQ or even storage tanks for veggie diesel oil. Just didn't have the money to buy them, even at $2/lb, which is cheap.

[bigjoeinkg]

I didn't get a chance to try one of these on AL after my son found it on my angle grinder. Look for a 3M product called Scotch-Brite Bristle Disk. There part number is 33054 for 36 grit (brown), 24241 for 50 grit (green), 24242 for 80 grit (yellow), and 24243 for 120 grit (white). I found my first one at AirGas in San Diego for $18. Worked great on open areas. Can't get into corners with them.

[jtybt]

Are those the discs like the scotch brite pads? I got some for my little air angle grinder. Didn't even think about those. I think I'll try them out. Gotta re-fill my argon first, though.

[Joe from NY]

Same problem here Tom. Nothing leaves the yard that comes in through the gates. It drives me crazy to see a huge pile of stainless steel I could use to build my ethanol plant but can't buy, beg, borrow or steel (pun intended).

Thurmond

It might be a local law issue. Over here, you need a "second hand dealer" license to resell things you purchased from people who walk in from the street, to other people who walk in from the street. My local scrap yards have such a license, because i can always walk around to see what i need. They are glad to sell it to me, as what they charge me is more than scrap value. If they could sell a whole dumpster of scrap to people at higher prices, they would love to do it. If they dont let you buy stuff there, they are either piss-poor businessmen, or dont have the correct license.

[Jason]

All the places I have gone around me wont give anything away. I think they make up the prices for each purchase made. I got some round bar one day and ended up short so the very next day I went to get some more and the rate had gone up over night.

[jojobead]

if you wire brush alum. and walk away u will notice it will start to oxidize quick.wire brush and adjust ac wave more on cleaning side(think 10% on +) of nitric acid but stuff stinks and may be hard to get

[jojobead]

clean with nitric acid

[jtybt]

Got muriatic acid and phosphoric acid. I think the muriatic is a bit strong so I tried the phosphoric. It cleaned it up some. I'll try some test beads tomorrow

[jakeru]

I've experimented with using both muriatic and phosphoric acid for aluminum welding prep, with pretty lackluster results. Both of these acids I found eat through not only the oxidation layer, but also into the clean aluminum underneath it as well (and quite rapidly eating into the clean aluminum.) Also, both will leave a hard, difficult to remove residue on the surface, that does not weld cleanly either. (Leaves black smut around the weld area.) Therefore, I would not recommend really using either of these acids for aluminum welding prep. I hope it works out for you. PS - vinegar (acetic acid) gave similar results as well, although takes a long time to work. Muriatic works the quickest.

I have a name brand "aluminum cleaner" I am going to try out for aluminum welding prep at some point. It is designed for this purpose. In addition to phosphoric acid, it contains a special/fancy ingredient in it ("aluminum bifluoride")

[performance]

Acetone won't deoxify, but it will clean residue. You need to be an organic chemist t opredict the interaction between the aluminum and the acids. Acetone has been proven safe. As far as experimenting with unproven chemicals, don't. It isn't safe. Some of the interaction can kill you, particularly when you put heat to it.

[jtybt]

OK, The nay sayers were right. It was FUGLY. I rinsed and scrubbed after the acid real good lat night and dried over 12 hrs. There was so much contamination that came up it looked like a pepper explosion.

I guess I gotta visit the scrap yard.

[EricCox]

I'm a welding noob, so I don't know how nitric acid cleans aluminum, but when I worked for an electronics manufacturer we used to use it to burn holes in the cases of silicon chips so the wafers inside could be examined under a microscope.

Be CAREFUL with nitric acid. Do it outside with a fan blowing the fumes into your neighbor's place. If you smell it at all, you're doing permanent damage to your lungs.