I’m very new to tig welding. Can the aluminum found at the Yard be tig welded. It has been sitting outside for close to forever?
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Yes, assuming it’s a weldable kind.
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How would I know? I’m guessing there’s some 7075 stuff there, cause that’s what chat gpt told me.
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I am not a welder, but 7075 is said to be unweldable:
There are other links for how machinable various aluminum alloys (i.e., 6061) are.
There is no aluminum alloy that does all things “the best”. Happy searching.
(P.S.: I like shopping “The Yard” too!)
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The yard has several aluminum alloys. They have a lot of 6061, usually t-6 or t-651. They also have 7075. I believe most of the extrusions are 6061. Sheet I’ve gotten is 2024 t-2, iirc. Iirc there is a color coding for the drops but I don’t recall what it is. Ask the guys in the shed. They should be able to point you in the right direction.
What are you wanting to make? Since you mentioned 7075, I’m guessing it’s from a block vs extrusion. Be aware that aluminum sinks heat like a mother. Welding a big block of it will require a lot of current.
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I built this using rivets. If the frame experiences too much torque then the rivets fail. It’s not going to really carry any weight to speak of so I was just hoping for a way to clean it up a bit and to make it look pretty.
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That’s all extrusion. It’s weldable.
I would definitely suggest practicing on some coupons first. And a TIG finger is a good thing to have if you think you might do more someday. Have you welded aluminum before?
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Lol I’ve only ever welded once before, stick. I’ve tried brazing aluminum, which didn’t go well. I’ve got time… My goals are to learn how to clean and deoxidize it, figure out a good setup for what I’ll be doing then practice a bunch.
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I used to oversee the Phosphoric acid anodize line [Boeing] and all its deox and other rinse tanks. I got around as senior inspector. I was NOT a line operator. But…
At home, I have both deoxed and anodized sheet 7075 [using a 6v battery] in a custom made long skinny tray/container. The attic vent louvers i made in 1989 are still up there on the house I used to own. Still No visible corrossion. Btw, I applied epoxy primer to phos anodize within 60 min, a very crucial timing step btw. Just like the <60 min deox to anodize timing step.
My time as weld inspector has been useful, but ive only welded steel on farm equipment and bicycles. I had a 6 weeks gas torch welding training once. Nobody calls me for my welding skills except ultraclean room welding shops having contamination challenges. Aluminim and SS and Ti. Im good for that still. Im more of an advisory Subject Matter Specialist. [And still being paid in that role]
I have seen 7075 welded, but i dont think such welds last. Pretty sure its too susceptible to Brittle Stress Corrossion cracking failure ?.. not because you CANT fuse it. But because it fatigues itself quickly.
Both these alloys (2024 & 7075) have a notable heat affected zone where the heat treat condition is … not advisable for structures. Glassy brittle failures, just from native leftover stresses. [Ok, If you are just building a mailbox or chicken coop, you may not care].
I have sweated together Al fittings using silver solder [brazing] but never with pretty joins. But grit blasting works deox wonders if you dont mind losing the mill surface polish.
If you aren’t building space craft, getting aluminum super clean isn’t really necessary. With AC welding, it will “clean” oxidation from the work piece. That’s not too say you can take a chunk of aluminum out of a mud puddle and start welding. You do need to clean it, but you don’t have to sand the oxide layer away.
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Even in aerospace… we dont always have to remove ALL of an oxide layer. But often, a chemical deox or an electropolish [etch] are quite easy, once you are in the tank line. Just add it to the operations recipe.
Just sometimes, as in orbital automatic welding, the oxidized layer might remain in large enuf [dirty?] pieces in the melt, that it can form a faint fracture line and not pass xray.
This frame job doesnt have that concern imo.
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Ive used hobart aluminium brazing rod, and it worked pretty good. Getting even heat over the whole piece was the trickiest part.
https://www.tractorsupply.com/tsc/product/hobart-aluminium-rod-pack-of-8
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I’m assuming you mean that you brazed your work with that? I wouldn’t recommend welding with a brazing rod.
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Yeah, sorry. I should have been more clear.
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