Using Helium for Aluminum Wheel Repair (jakeru's #19)

[jakeru]

The customer is a professional wheel repair company, (and they are very skilled at grinding, straightening, and painting), so when doing welding jobs for them I worry about: leaving no low spots, leaving no stress risers (especially if it is likely that they will be bending them straight afterwards, as they usually do this immediately after receiving my welded wheels before and grinding), and leaving no porosity in any weld deposit. I don't need to worry about grinding, polishing, and painting, as this is what they do (and they do it really well; you usually can't even tell the wheel was worked on after they are done with it.) I'm pretty happy with the arrangement.

I have done some final grinding/polishing on wheels but they are usually one-off projects for friends, and for some reason I seem to never take pictures of those projects. I did one for my brother about a week or two ago, it was an old bare polished aluminum wheel for a 1960's Chevy van. (They call them "mag" wheels but they were really aluminum.) Reconstructed the inner wheel lip where it was broken off. Ground the welded bead down with a flap wheel using a light touch and taking my time. No paint. Oh, we did do some "hot bending" with a weed burner and a big hammer on the wheel lip beforehand on that wheel too.

Just last night, I ground some "curbage" out of the outer wheel lip of a painted cast wheel for a friend. (Purely for cosmetic reasons.) He had selected and tested a spray paint that was a near perfect color match, he was going to shoot over it. Didn't get any pics of that one either.

[Tritium]

I am mixing argon and c02 for my mig welding. I can't see the need to buy a separate setup when I have the pure products on hand. I may try some O2 in the mix since some of the mig gasses are a tri-mix for stainless and regular low alloy steel.

Thurmond

[everlastsupport]

I am mixing argon and c02 for my mig welding. I can't see the need to buy a separate setup when I have the pure products on hand. I may try some O2 in the mix since some of the mig gasses are a tri-mix for stainless and regular low alloy steel.

Thurmond

Order some C18 or C25 for MIG. I would not bother mixing unless you are doing TIG on aluminum.

[jakeru]

Something remarkable I've discovered with the helium mix, at least at high penetration AC Balance settings (80% EN), is that it seems to take a lot of heat off the tungsten compared to using the same current with pure argon.

Check out the pictures below. This was a crack repair of a .6" thick lip of an aluminum, automotive wheel, which is about the thickest wheel lip I have seen in such an application. It was also a 20"x9" wheel, and further stored in below freezing shop, so pretty big heat sink that needed a lot of heat to weld... 200 amps sustained for several seconds at a time, to be precise. I did grind a vee with a carbide burr on both sides and weld both sides, as was necessary to pull this off with full penetration with anywhere near of as narrow of a weld bead as is shown.



I used the same helium mix I have been using for a few months now for a lot of my aluminum, which is, in the general ballpark mix of about 25% He. But get this... I did this with a 1/16" tungsten! Sorry I didn't take a before pic, but it started out as a truncated point, like a crayon shape. It is a 2% lanthanated. Here is what it looked like after:



It's got some "multiple protrusions", (so is definitely pushing the current limits on it without balling it), but, what's amazing to me is, how the tip didn't melt right off and drop into the aluminum puddle, or even completely "ball" at this current level! I am almost certain if I were using pure argon at 200 amps sustained for several seconds, it would have melted at least a pretty nice sized ball, and maybe even dripped the molten tungsten tip right off. What do you guys think?

So, putting aside the benefits of the extra and penetration per amp that Helium allows, it seems like there is an additional benefit, that it allows you to run a smaller tungsten (providing further more focused, controllable, and penetrating heat on thick materials.)

End result: the crack in the .6" thick wheel, I was able to repair with full penetration (from both sides) with the Helium mix and a 1/16" tungsten, with a measured bead width of only .35", (that's just a little bit over half the thickness of the material) without really even trying that hard. I don't think that would have been possible with pure argon.

(Now in hindsight, I could have further turned up the He% to try further increasing heat per amp, and probably welded this without even needing 200 amps, but I wanted to try this thick wheel with my "usual mix" to see how the tungsten would hold.)

[hooda]

Note to self "get some helium"

[jakeru]

I ran out of argon tonight, and to get a project done (aluminum) I tried cranking up the Helium and just running pure (100%) Helium. The red arc, black "soot" nastiness came back, and then in between weld beads, I was also reminded about the hard arc starts. I had to really push down on the pedal quite a bit, even with the 1/16" tungsten to get the arc to start. (although the tip was about as blunt as can be )

I don't know what's up with all that, but a mix of a little Helium, with a lot of Argon is definitely where my welding setup is happiest at the moment.

I will continue to mix my own He/Ar mix, because it seems to be the most economical to do it that way. Plus, I have a much easier time refilling my smaller (155cf) Argon bottle than my larger 330cf Helium bottle, due to it being easier to transport for me. I am down to about 1500 psi on the Helium bottle - I think it started at about 2500psi, so I've used up 40% of it so far.

[everlastsupport]

Jake,

Just baiting for more pictures.

I know the friend projects. God do I know them.

Maybe they can show the final repair? Or you can cop a picture.

You might want to explain MAG welding too.