Why aren't all cars stainless steel?

[RammJaeger]

Not 100% Delorean related, but this week I went to check on the progress on my 1969 Charger that I'm having a bunch of body work done on (replace/repair all the rust, new paint job, etc). The car looked pretty decent on the surface, but once they started grinding away the paint they found a lot of rust, and once they started cutting away the rusty bits they found even more rust. They ended up needing to cut out the entire lower quarter panels and the entire trunk floor. I've attached some pics for reference.

Anyway, this got me thinking - why don't they make all cars out of stainless steel? One of the things I love about my Delorean is that even though its 30 years old, its body can't rust (I know the frame can of course). So why don't they make all cars out of stainless. Is it way more expensive? Is it more difficult to form into shape? Do the "evil" car companies just want our cars to rust away so we buy new ones? What do you guys think?

[Patrick C]

why don't they make all cars out of stainless. Is it way more expensive?

Much more expensive, and much harder to repair stainless bodywork.

[Spittybug]

Do you believe Detroit wants ALL of the cars they make to last as long as a Delorean? $$$$$$$$$$$$$$$$$$$$$$$$$$$$$.

[Rich]

It's a good question.

The answers so far make sense.

And, as you noted the body of the D isn't completely made of stainless steel. More like "made with stainless steel". Its construction can be described as a coated steel frame with a stainless steel-clad fiberglass body shell and stainless steel doors.

There aren't many modern cars that can have all of the fenders and quarter panels removed and replaced without a single cut or weld. Maybe none.

[David T]

It's a good question.

The answers so far make sense.

And, as you noted the body of the D isn't completely made of stainless steel. More like "made with stainless steel". Its construction can be described as a coated steel frame with a stainless steel-clad fiberglass body shell and stainless steel doors.

There aren't many modern cars that can have all of the fenders and quarter panels removed and replaced without a single cut or weld. Maybe none.

The main reasons are cost and weight. Steel parts are a lot cheaper than S/S parts and the tooling is also cheaper. Some of the cost is defrayed because you do not have to paint the parts but color is a very big marketing tool. Shaving weight on cars today is a very big deal. It is the cheapest thing you can do to improve efficiency, increase gas mileage, and lower costs. One reason you are seeing more and more plastic and composite parts being used. Resistance to corrosion is way down on the list of priorities but is desirable. Just not at increased cost. As for making it easier to repair, that is the insurance company's problem. No one seems to care about it when they choose a new vehicle. There is a built-in interest to build a car that will only last for a certain (short) period of time. In many cases the owner gets tired of the car before it wears out anyway.
David Teitelbaum

[Totally 80s]

Also Stainless Steel isn't that great a material for cars. Its hard to keep clean, fingerprints, gets nasty stuff in the grain, gets bad swirl marks if not grained/cleaned perfectly, hard to paint, hard to repair, etc. etc. It's a gimmick, a cool gimmick but a gimmick none the less.

[Bitsyncmaster]

Boy it drives me nuts when people think SS is heavier than cold rolled steel.:smashfreak:


Kg/M^3
Stainless Steel 7480 - 8000
Steel 7850

[beernpizzalover]

Not 100% Delorean related, but this week I went to check on the progress on my 1969 Charger that I'm having a bunch of body work done on (replace/repair all the rust, new paint job, etc). The car looked pretty decent on the surface, but once they started grinding away the paint they found a lot of rust, and once they started cutting away the rusty bits they found even more rust. They ended up needing to cut out the entire lower quarter panels and the entire trunk floor. I've attached some pics for reference.

Anyway, this got me thinking - why don't they make all cars out of stainless steel? One of the things I love about my Delorean is that even though its 30 years old, its body can't rust (I know the frame can of course). So why don't they make all cars out of stainless. Is it way more expensive? Is it more difficult to form into shape? Do the "evil" car companies just want our cars to rust away so we buy new ones? What do you guys think?

I believe stainless steel is about five times more expensive than the typical mild steel that most cars are made out of, according to a documentary I watched once. But it's the look of the car itself that makes it so alluring!

[Josh]

I believe stainless steel is about five times more expensive than the typical mild steel that most cars are made out of, according to a documentary I watched once. But it's the look of the car itself that makes it so alluring!
I regularly get parts laser cut. Once I got my delorean I started inquiring about SS pieces. a 4x8 sheet of 316 SS (the delorean uses a cheaper grade of SS) is about 4 times more expensive than mild A36 steel of the same thickness.

[DeMopar]

Not 100% Delorean related, but this week I went to check on the progress on my 1969 Charger that I'm having a bunch of body work done on (replace/repair all the rust, new paint job, etc). The car looked pretty decent on the surface, but once they started grinding away the paint they found a lot of rust, and once they started cutting away the rusty bits they found even more rust. They ended up needing to cut out the entire lower quarter panels and the entire trunk floor. I've attached some pics for reference.

Anyway, this got me thinking - why don't they make all cars out of stainless steel? One of the things I love about my Delorean is that even though its 30 years old, its body can't rust (I know the frame can of course). So why don't they make all cars out of stainless. Is it way more expensive? Is it more difficult to form into shape? Do the "evil" car companies just want our cars to rust away so we buy new ones? What do you guys think?


I think that's a lot of work! But those cars are pretty hot right now. Is your Charger an R/T? What size motor, etc?

[Bitsyncmaster]

I regularly get parts laser cut. Once I got my delorean I started inquiring about SS pieces. a 4x8 sheet of 316 SS (the delorean uses a cheaper grade of SS) is about 4 times more expensive than mild A36 steel of the same thickness.

That's about what I found also.

[beernpizzalover]

I regularly get parts laser cut. Once I got my delorean I started inquiring about SS pieces. a 4x8 sheet of 316 SS (the delorean uses a cheaper grade of SS) is about 4 times more expensive than mild A36 steel of the same thickness.

I believe the DMC-12 uses ASTM-317, according to a spec sheet I have.

[RammJaeger]

I think that's a lot of work! But those cars are pretty hot right now. Is your Charger an R/T? What size motor, etc?

It is an R/T with a 440, power steering and power disk brakes, AC, lots of options. Some time I'll post a thread up in the off topic section with some pictures (before this current batch of work).

[Nicholas R]

I believe the DMC-12 uses ASTM-317, according to a spec sheet I have.

Where did you get this spec sheet??? The Delorean is good old 304 stainless and that's it. 317 would be way overkill for car body panels. There has to be a specific need for 317 to justify the cost of 317. 317 is more expensive than 316, which is a lot more expensive than 304. We have SS panels because they look cool and because they're pretty rust resistant; but not because we subject our cars to acid baths or heavily load them.

[Kenny_Z]

I ask myself the same question whenever I dive into my Nova or Mustang projects. I hate rust. I think that's the main reason I consider the DeLorean the easiest car I've ever worked restore. Even engine access was easier. No bending over a fender or engine bay.

[Dangermouse]

The real question is - are you repairing the Charger with SS?

[RammJaeger]

The real question is - are you repairing the Charger with SS?

If they made stainless steel body panels for the Charger I probably would :)

[DeMopar]

It is an R/T with a 440, power steering and power disk brakes, AC, lots of options. Some time I'll post a thread up in the off topic section with some pictures (before this current batch of work).

Yes! Please do!

[RammJaeger]

Yes! Please do!

Here you go, pics of my Charger and my other non-D cars :)

http://dmctalk.org/showthread.php?7517-Official-Pictures-of-Other-%28Non-D%29-Cars-You-Own&p=115034&viewfull=1#post115034

[dustybarn]

Stainless is also difficult to stamp compared to carbon steel. The good folks at Lapple in Carlow had a heckuva time stamping the panels without splits and without harming the brushed finish (which was applied at the mill, prior to stamping). The wear to the dies was unusually high as well.

And this was on a car with relatively gentle contours. The sharp edges that are prevalent on modern cars would be a nightmare to make in stainless.

Lots of good info at http://www.delorean.ie/lapple.html

[Exolis]

Stainless is also difficult to stamp compared to carbon steel. The good folks at Lapple in Carlow had a heckuva time stamping the panels without splits and without harming the brushed finish (which was applied at the mill, prior to stamping). The wear to the dies was unusually high as well.

And this was on a car with relatively gentle contours. The sharp edges that are prevalent on modern cars would be a nightmare to make in stainless.

Lots of good info at http://www.delorean.ie/lapple.html

^^ This is probably main reason, though it does tie in with costs.

I asked my Uncle(owns his own Tool and Dye shop) about the cost of stamping SS and he said it would be costly and difficult to do. I believe he said you would also need to have the die bend it more then desired amount as it will flex back.

Also considering most cars are Body Frames, this would be insanely expensive. It's not really so much Automotive OEMs want cars to die so you buy new, it's the fact no one would be able to afford a vehicle if it was all SS. If it were a Special Edition/Luxury car that had SS, it would make sense and be neat. But something like an Altima, would probably cost at least double the price. Though would be interesting to see how much it would in theory cost...

[D Knight]

The cost of a finished stamped SS panel is very close to a stamped painted panel. The dies and r and d are where it gets a little higher. Painted panels are also EDP coated, sealed, painted, then cleared and cut and rubbed out. That is an added cost to the panel most people forget about. They don't want your car to last forever-they couldn't care less as long as it outlasts the warranty period. The initial buy in to the tooling is also a deterant.

[Exolis]

The cost of a finished stamped SS panel is very close to a stamped painted panel. The dies and r and d are where it gets a little higher. Painted panels are also EDP coated, sealed, painted, then cleared and cut and rubbed out. That is an added cost to the panel most people forget about. They don't want your car to last forever-they couldn't care less as long as it outlasts the warranty period. The initial buy in to the tooling is also a deterant.

You would be surprised, but most (if not all) Automotive OEMs want their cars to last a long time, if a vehicle is still in good shape after warranty period, then it remains to have a higher resell value. Having a long lasting car will also build customer trust and loyalty. OEMs pretty much function based on different 3rd party reports such as JD Powers, Consumer Report, IQS, etc; which they all rate cars on initial quality, reliability and longevity of the vehicle.

[ccurzio]

You would be surprised, but most (if not all) Automotive OEMs want their cars to last a long time

No they don't. If car companies built their cars to last, nobody except the model-hoppers would ever buy a new car. And the people who can afford to model hop already do it anyway.

Car manufacturers don't give a rat's ass about resale value. They don't see a penny off those sales.

That's not to say that super reliable cars don't exist, but don't delude yourself into thinking that car manufacturers would have a sustainable business model by building cars to last forever.

[Jimmyvonviggle]

I agree with you Chris, car companies only want their cars to last past the warranty phase. And only issue a recall if they are forced to or feel they will be.

[Ron]

They want them to last a little longer than that....Dealers aren't making all their money off of new car sales.

[ccurzio]

They want them to last a little longer than that....Dealers aren't making all their money off of new car sales.

Dealers aren't car manufacturers.

[Jonathan]

Stainless is rust resistant, as we know, but not to everything. Stainless does not hold up well under the presence of chlorides.

I'm not sure how this applies long term to car parts, but in the desalination water systems I've worked on, we don't normally use stainless on the piping that is in contact with high salinity water. Now, keep in mind, sea water chlorides can get up really really high, especially in the portions of a membrane based system that concentrates one stream. It's likely a lot more than what it might be if measured dripping off your quarter panel, but when piping is immersed in sea water 24/7, if shortens the life of the system and components.

Plastic pipe can't always handle the high pressures and many other metals get pretty expensive (not saying stainless isn't expensive in the first place!). Hastelloy C can be used as well as certain linings within piping of varying materials.

There might also be the issue of where stainless to stainless fasteners can fuse to themselves. It can be related to the edges of threads or openings being very fine and the two sides get fused to each other. Not a good scenario either. But using dissimilar metals in your fasteners is more doable/cheaper than entire body panels being made rust resistant.

[Exolis]

Well, I might be drinking the cool aid, but working at Nissan and having friends and family working at other OEMs around town, reliability is the main focus of R&D. Anyone can make and sell a car, all cars will get you from point A to point B and have similar features. The main difference in which sets the OEM competition is Reliability, even Resell value is a strong point. If someone leases a car for 3 years and it's a piece of crap by the time it's turned in, then it has little resell value so you will end up having to pay more on your lease, people want to pay less, so having a higher resell value it will be better for the buyer because they know they can either turn in their car or sell it off later.

Also, having a more reliable car creates a better image for the company which gets the company returning customers. I agree, no company will make a car that will last 20+ years with little maintenance because it's essentially impossible to do. Every OEM and Supplier would have to spend so much more money to make things last that long that eventually the cost will end up being significantly higher to the point where no one would buy the car.

For example, the new Pathfinder had a pretty rough launch due to supplier issues(along with several other launches). That gave Nissan a low JD Power IQS rating (http://autos.jdpower.com/content/press-release/3WScQEz/2013-j-d-power-initial-quality-study.htm). However the Pathfinder has been selling very well and even passed Arcadia and Traverse. Even though Chevy and GMC are higher, our Higher ups stress more and focusing on make the vehicles better to put that rating back up.

Granted it's good for the company to sell lots of product, but it's not to say the OEMs don't give a shit about the vehicle once it's sold or once the car has passed warranty period because that defiantly is not true.

[Ron]

Dealers aren't car manufacturers. It doesn't matter since they can't survive without each other.

Manufacturers can make vehicles fail virtually whenever they choose, even within a few thousand miles after the mileage warranty expired. They don't because it would kill the dealerships. Dealers make way over half of their profits from parts and service, then financing, used car deals, etc., with new car sales representing less than 10%! (years after the warranty period) If manufactures gave dealers 'Timexes', they would go the way of the watchmaker... Manufacturers would loose the shared cost of: marketing and sales, parts storage (mandated for years, in some cases), warranty service (technicians, equipment, etc). Who would store new vehicles, where?
Not to mention consumers learn which products offer the best gamble....

[Starglider]

Galvanised steel has the same or better corrosion resistance than stainless and is significantly cheaper. Essentially all Audis have galvanised bodies for this reason.

[Ron]

Me thinks not...

[Mark D]

Galvanised steel has the same or better corrosion resistance than stainless and is significantly cheaper. Essentially all Audis have galvanised bodies for this reason.

I would be more careful making a statement like that as if it were a fact without checking your information first. I'll also forgive your incorrect spelling of "Galvanized" since you're in the UK. :poke:

:smile:

Galvanized steel can provide corrosion protection close to that of stainless steel under certain conditions but the zinc coating is by definition sacrificial and will eventually decay to the point where the underlying mild steel is exposed. Galvanizing is just another type of coating to protect the base metal below.

Corrosion of the outer zinc layer will actually occur rapidly if the metal does not have a chance to dry out periodically and reform a protective zinc oxide layer. If you look up the salt spray numbers for galvanized steel you'll see that they aren't much better than raw mild steel because of how quickly the zinc is eaten away under continuous spray conditions.

Stainless on the other hand contains chromium and nickel (in varying percentages depending on the grade of SS) and the chromium within the metal forms an oxide layer that prevents corrosion.

There is no doubt that in 10-15 years you'll be able to find galvanized Audi bodies rusting away in a junk yard somewhere. You won't be seeing any DeLoreans with rusting panels sitting next to them.

[Josh]

Galvanised steel has the same or better corrosion resistance than stainless and is significantly cheaper. Essentially all Audis have galvanised bodies for this reason.

No... So now my galvanised frame is better than a S/S frame? I doubt that!

Im sure it will be addressed further but a major thing with galvanizing is it is a sacrificial coating. It will eventually wear away to nothing exposing the metal underneath.

Many cars have galvanized panels, not just fancy ones. My 2007 chevy cobalt had a galvanized body. (well a hood and fenders at least, the rock chips never rusted)

[Nicholas R]

Maybe we should consider adding sacrificial anodes to the frames of our cars to prevent corrosion. Since the electrical system already grounds through the frame, the flow of electrons should take place.