Welding a crack in Momo Prototipo

[PeterM1965]

I have a black flat 350mm Prototipo with a crack in one spoke. Has anybody had a cracked Prototipo welded? If so, by whom?

Thanks
Peter M

[Harvey Weidman]

I would not weld a crack in that area. There is too much flex. When the aluminum stock wheels cracked, we retired them.
My .02
H

[PeterM1965]

Thanks Harvey. I will be hanging this on my garage wall.

Peter

[PeterM1965]

Raj

I remember that post. Pretty cool.

Thanks
Peter

[PeterM1965]

Hi Nick, I've thought about that as well. Not welding, but bonding it with some type of industrial adhesive. I just bought a 370mm flat Momo to replace this wheel. So now I have the opportunity to play around with it a bit.

Thanks
Peter

[E911]

This is my early momo that was welded up after someone broke it pushing the car around in storage. I too am looking for someone that can clean it up and refinish it. Is the consensus here that it won't hold up?

[docrodg]

Considering the position ot the steering wheel in a crash repairing the wheel in any manner that would permit if to break during a crash could be catastrophic for you. During a crash the wheel shoiuld deform, thus absorbing the forces of your chest hitting it. If it does not deform and stays intact you will at a minimum break several ribs on your chest, possibly causing a flail chest which prevents one lung from inflating and is life threatening. If it breaks then it could impale you and thus cause major trauma such as a pneumothorax, hemothorax, pneumohemothorx, or cardiac tamponade. That would certainly kill you if you are not very close to a good trauma center and have a good medic taking care of you. Any repair would have to stand up to the force of your upper body hitting the wheel in a crash. An average 180lb person is 60% upper body weight, driving at 60mph this person would hit the wheel with 381600 pounds of force (mass x velocity^2).

Now... care to trust that repair?

[E911]

I thought the seat belt was designed to handle the job of not impaling yourself on the hub? I'm trying to imagine the welded alloy versus the non-welded original item making one iota of difference in a situation where your 60s or 70s designed car comes to a violent stop that supplies that much energy to the wheel. The fact that it's broken kinda of makes that point.

Still wondering if there is someone out there that can refinish these wheels to a high standard... whether it ever makes it back on my car or not.

[PeterM1965]

I'm more concerned with structural failure of the spoke and subsequent loss of control. Docrodg's safety point is one I had not considered but it is valid as well.

That being said, if safety were my main concern I wouldn't be out in a lowered SWB 911 dicing it up with cars and trucks at least twice my size. But neither do I need to increase my already elevated chance of injury.

I do consider driving my car to be a risky proposition, not as dangerous as a motorcycle, but not as safe as my M5. That is, in fact, one of the thrills of driving it.

But being a tinkerer and just a bit curious, I would like to see whether or not the wheel could be fixed just for the sake of it.

Peter

[LongRanger]

. . . I'm more concerned with structural failure of the spoke and subsequent loss of control . . . But being a tinkerer and just a bit curious, I would like to see whether or not the wheel could be fixed just for the sake of it . . .

Spent some years working in aerospace --- fabrication/assembly of structures/flight systems + controls/engines/etc . . . commercial/military/space/black projects. Saw a lot of stuff done with/to metal . . . amazing stuff

Can that busted spoke be repaired?

Sure. Just take off the covering, strip/clean/re-weld the damaged area . . . with the proper rod, by a trained/certified operator, using calibrated equipment . . . then anneal/heat-treat the material back to the suitable/appropriate hardness, grind down the repaired area to your satisfaction, crack-check it (fluorescent penetrant/X-ray/mag particle/etc), re-anodize/paint/powder coat to taste, then re-cover

Will the resulting wheel look good?

Sure. Like new


Will the resulting wheel be as structurally sound/strong as an original/un-broken/never damaged one?

Nope


Would I trust this bit to steer my car and its occupants safely?

No

(HELL no)


But that's just me

From my experience, I don't repair structural (load-bearing) aluminum


I replace it