Cybertruck Body Rust

[TugboatEng]

I know this is being weaponized against against Tesla for obvious reasons but I also believe this is going to be a serious and real black mark against the company. Stainless steels don't tolerate dirty environments and road dust plus morning dew constitutes a dirty environment. I feel, not knowing the specific alloy, that these bodies are going to require regular abrasive cleaning or caustic+acid washing. Tesla hasn't said much about the alloy other than giving it a fancy name like 30X Hard. I assume 30X refers to a 300 series stainless steel which are especially sensitive to crevice corrosion. Maybe 305, a deep drawing stainless is the material?

 

[3DDave]

The only obvious reason is Tesla is famous for poor fit and finish. They managed to bring back a level of build quality the US automakers managed to escape in the 1970s and fit and finish in the 1970s still stunk. I recall a radiator strap that was cushioned with actual interior grade corner trim, complete with faux-wood finish, as one might get at a big box building supply.

Not to worry, the non-stainless frames underneath will likely self-destruct before the first hole corrodes through.

What is more likely to happen is what happened to a large number of Deloreans when owners discovered that trying to deal with any abrasion, scratch, dent, or other surface defect was met with the nearly impossible task of trying to match the brushed surface and so they gave up and got the car painted.

 

[GregLocock]

Hard to believe they didn't notice this during the rather long development of the truck. My experience with SS is that 304 is only sort of stainless, but have rejected a batch of 316 that was almost as bad.

Cheers

Greg Locock


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[BrianPetersen]

Oh, it was probably noticed, but you can't tell the great leader that one of his ideas is bad. "You will make this work, or I will find someone who can." Yes, boss.

 

[ctopher]

My son has 2 Tesla's, have friends with them. So far, we have not seen any problems with fit/finish. We have checked.
I guess the wash test on the Cybertruck wasn't enough?

Chris, CSWP
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[IRstuff]

But, Musk knows more about manufacturing than anyone in the world, how come something like that happen?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[EdStainless]

If the alloy is high strength I suspect that it is a 200 series alloy.
With the extra Mn and N they like to roll to very high strengths.
In many of these grades you can get 150ksi UTS/125ksi Yield/20% elong.
And crevice corrosion on dirty SS is very common.
Just wait until someone puts a sticker on it and ends up with pits outlining the shape.
One of the real problems is that wherever you touch it with a steel item you will leave a trace of material.
And this will start rusting. And while it isn't het SS rusting it leaves a rust streak.
And it does make it more likely that the SS beneath will pit also.

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[3DDave]

See how hard it is for Tesla to escape their first many years of sloppy production?

It still surprises me that a bare metal finish on a vehicle was put into production. Chrome is barely up to the job as I recall from the rusting chrome bumpers and wheel nut covers.

 

[ctopher]

Browsing, found these, little info.
Link
https://www.capitalone.com/cars/learn/finding-the-right-car/at-tesla-hfs-is-short-for-stainless-steel/2977]Link[/url]
Link

Chris, CSWP
SolidWorks
ctophers home

 

[EdStainless]

I have ridden in the Allegheny Ludlum SS Lincoln, and I have seen the older ones.
They used to let salesmen drive them around all of the time.
The only rules were that they had to be kept clean.
One of the guys told me that he had it washed twice a week so that it always looked good.
A bunch of these cars were sold in 2020, I am not sure where they are now.

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[thebard3]

If I get a scratch in my car door, the body shop wants to paint the whole side to ensure a color match. I don't think Tesla ever advertised the finish as trouble free. As with anything new, the customers usually end up performing (and paying for) some of the R&D. Some new and innovative methods will be required to maintain and repair these. If you want to see corrosion, well, I'll just show you a picture of my 2500 HD (or any other vehicle) after a decade of parking lot dings and Ohio road salt.

Brad Waybright

The more you know, the more you know you don't know.

 

[EdStainless]

One thing that aggravates the Tesla issues is that there is no one to go to get things fixed.
Just think of the mess if they ever need to physically recall vehicles.

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[TugboatEng]

I haven't seen one closely enough to see the surface finish. If they're brushed that can be repaired by hand. Tesla should provide a kit for customers with the correct chemicals and abrasives to maintain the brushed finish.

If they're media blasted or electrically finished, that would be a problem to touch up without having refinish the entire panel or body.

 

[enginesrus]

I suppose Tesla will need to now use either a quality 321 stainless, or inconel.

 

[SWComposites]

Why Inconel??? Very expensive and only needed for high temperature conditions.

 

[MintJulep]

There are 10's of thousands, maybe more, subway, commuter, regional and long distance trains worldwide that are built from 300 series stainless. Mostly 304L, but also 301L.

They are not failing from crevice corrosion.

 

[TugboatEng]

And 321 has similar corrosion resistance to the typical 304 grade and has less resistance than 316 which still isn't really suitable for this application.

Yes, if you get your nickel high enough you won't have crevice corrosion. That would be Inconel. You can save money on chromium and use Monel. 254 SMO would also work well.

Regular polishing or 316 stainless steel will work but that would change the appearance from brushed and this truck was advertised as being durable.

I figured this would be a good chance to introduce everyone to the concept of crevice corrosion. Most stainless steels are highly sensitive to this problem and it can happen in open air (air is dirty). I especially want our electrical engineers to see this and recognize the problems caused by spot welded flanges and hinges on enclosures.

Mint, I thought those bodies were aluminum. If SS, they also likely get regularly washed. There is a company, Integument, that applies fluoroelastomer films to those bodies. If there is corrosion, they aren't held to the same level of scrutiny. The Cybertruck bodies are staining, they're not failing in any serious way. Aluminum is also subject to crevice corrosion.

 

[spsalso]

Budd was building stainless passenger cars for years--since before WWII. Some are still around.

They likely didn't/don't get much salt exposure, though.



spsalso

 

[TugboatEng]

Don't forget about Delorean. A bit of googling reveals similar issues. I don't think the Delorean was ever advertised as anything more than a novelty. Tesla maybe overstated what their body could do.

Budd also built a SS airplane.

 

[davidbeach]

So, that DeLorean that I never bought would have had the same issues with the Tesla that I'll never buy... Yawn...

When one this sentence into the German to translate wanted, would one the fact exploit, that the word order and the punctuation already with the German conventions agree.

-- Douglas Hofstadter, Jan 1982