Aluminum Wheel Troubles

by Vince Bunting
(Long Beach, CA USA)

Hey Jody.. .First off your site is amazing and I can't tell you how much I've learned or how many hours I've spent reading material on this site. I have an unusual aluminum wheel off a late model Mercedes. This wheel has been through the unfortunate event of almost falling off due to striped threads in the hub. The face where the wheel mounts is all banged up with some deep gouges. The only person who is willing to sell me a rim wants $4,000 for it. Soooo. . .I'm going to try and repair it. My plan is to pre-heat it in an oven to around 400 degrees and weld it with a argon/helium blend.

1st: I have no idea what type of aluminum this is. . .what filler rod would you recommend? I have to build up the face and then machine it.

2nd: Is there any advantage to blending your own argon/helium mix as you do in your shop. I have used a pre-mixed blend to great effect before but am curious if a larger helium to argon ratio would increase my penetration. I have read somewhere that automated welders sometimes use straight helium for penetration. If there is an advantage to being able to play with the ratios this job would be a good time for me to invest in a new setup.

Thank you advance for any tips that will save my butt on this and for your willingness to share your craft with others!!!

Vinny

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Vinny,

a 200 f preheat will do.

I dont mix my own helium to get a certain percentage. Sometimes I use straight helium on aluminum...its rare and the aluminum has to be ultra clean. But thats why I mix .

you could get a cylinder of 50/50 or 80% helium and be just fine.

a way to get an idea of the alloy is to puddle a small area.

if you see a green tint on clean metal, it might be an aluminum alloyed with magnesium...

more thank likely, its a silicon alloyed aluminum casting and can be welded with 4043.