Car Tech forum: What are the pros and cons of plastic cars?

I don't want my car to disintergrate if someone hits me, or if I hit them.

Plastic does not always look new, unless you know of something different than I do. My metal doors (that I keep clean) look way better than my sisters plastic car doors.

I'm not sure what "tune can tin" you mean. I've sat on the hood of my 82 Buick without any dent. I think you are comparing the crappy paper thin metal used on a eco-nut midget mobile car to plastic. In which case the metal might be worse. But compared to older cars, or most truck/SUV metal, then the story changes. Older cars, and SUVs/trucks with lower CAFE requirements, have thicker tougher metal, and plastic isn't even a match for it. Now if you are talking about little Cavaliers and tiny Honda's, yeah that metal is so thin and weak, you got a point.

Well I can't answer for everyone else, but my 82 Buick has been hit twice. Both times the plastic car lost, big time. I don't even have a scratch from either hit. But the plastic other cars sure do. One was so messed up, it looked like a bull dogs face on the front.

You can get with the future. I'll be in my 82. You best not run into me, cause you'll lose.

Yes, cars are made of crappy metal. I said that in another post. But the issue is, it doesn't have to be crappy metal. Case and point, my fathers Tahoe and mothers PT Cruiser went through a hail storm. The Tahoe had no damage, the PT was all messed up.

It is government regulations that force auto makers to use paper thin metal. If that was not the case, metal would not be crappy, and it would still be way safer than plastic. Plastic will never be a good replacement for decent steal.

This is way I'll likely always drive an old car. I can't stand plastic cars or cars with cheezy paper thin metal.

Trucks should not be plastic. If I was off-roading in the middle of no where, and if i roll my truck, i want [the panels] to bend, not crack in half, or become discolored, or lose severe body strength due to it stretching. After a roll-over, i want to be able to go home, take the panel off, and hammer it out. And if i'm towing, I want it to be able to handle the added stress. If im towing a 15,000 # goseneck, I dont want it breaking, I want it to be tough, and be able to do it over and over again..

just my $.02

Usually, the people on this forum are well informed and know their facts. Not this time. We have people saying plastic is recyclable and that it isn't. That plastic-bodied cars are more dangerous in an accident and that they aren't. That they're safer in thunderstorms and that it doesn't matter. I could go on.

Until we have a lot more accurate information than we've displayed, I don't think this discussion is going to go anywhere.

Yes government has made it so auto manufactures have to use super thin metal. It's horrible but true. I just hate plastic because it provides no real protection.

We could use carbon fiber composite, but it is way to expensive. No ones going to pay $30K for a tiny car made from Carbon Fiber.

I really don't know of any useable material that can be re-used besides metal. Do you?

Granted I don't trust government one bit, but it's not a conspiracy. It's the law of "unintended consquences".

The conspiracy nuts are the ones who believe that automakers "must have the technology" to make a car that seats 6, has plenty of cargo space, and is safe like a tank, yet gets 60 miles per gallon.

Those people elect people who create and increase CAFE standards. Now the goal was for car makers to make better cars, but the result, instead of being super cars that do everything, are safe, and get great gasmileage, is that you end up with little tiny midget mobiles with paper thin sheet metal.

Like I posted before, my father has an SUV, and mother has a PT Cruiser. Little bit of hail, the PT is more bumpy than a zit covered teenager, and the Tahoe is solid and smooth.

Why? SUV/trucks have lower CAFE standards, so they can, and do, use thinker sheet metal that's tough.

Now back to the question: What other material is there that is useable on autos that is recycleable? Metal obviously is. But plastic and fiber glass isn't. So what's the other option(s)? I honestly do not know, so tell me.

BTW, I know of carbon fiber composite, no clue if you can recycle it, but it surely isn't affordable. I'm not paying $50K for a carbon fiber Geo Metro.

Cold weather, such as what we have in the Midwest, doesn't mix with what becomes frozen, brittle, plastic. My front bumper was instantly crushed from a small bump this past winter. If it had been summer, there would have been no damage at all. I would NOT buy a plastic car!!!

Have you ever seen a Saturn, mostly plastic, after a engine fire? It starts at the front and burns all the way to the back. All that is left is the engine/transmission and some of the steel cage parts. Very impressive!

Not so. In a metal car, the firewall should, in many cases, prevent or at least delay an engine fire from spreading to the passenger compartment. Also, in older cars, the trunk was also isolated. No longer as most of the time back seats fold down revealing access to the trunk.

However when your door and quarter panels are made of plastics, the fire can jump around the firewall pretty easy. However, car fires are not nearly as prevalent and safety features all around, make a fire not really a large enough factor to deal with for this discussion.

Bottom line: a car fire isn't a big enough issue to use as a reason against plastic.

The latest Boeing jetliners are being constructed of plastics this material is lighter and stronger then aluminum thus yielding a more "green" aircraft.

Why not cars!?

I am on my 3rd Saturn. In my second one (a SW2 Station Wagon), I hit a tree doing about 55MPH. I left the road doing about 70, took out a 4x4 mailbox post then hit the tree square on the passenger side. My front right wheel, with tie rods/suspension parts still attached, ended up about 30' away smack dab in the middle of the road I was just on.

The car was totaled. All I got were some scuff marks on the inside of my arms and a small burn on a thumb from the hot gas inside the air bag. Facts are facts and thats my experience.

Ax

Worried about plastics and other composites in your vehicles? Well, think about it this way: Most modern, if not all, jet fighters are made mostly of composites. These are vehicles designed to take 9-G turns and survive getting shot at with 50-caliber projectiles. Can your steel-only construction car take that abuse?

Yes, the average joe can afford composites. Composite materials and alloys are easily and plentifully produced. The ultra-high quality composites used in airplanes and fighter jets are a very minor factor when speaking of costs. I just going to go out on a limb and assume it's the billions of dollars in research, jet engines, missiles and other fighting technology that make those planes expensive.

The average joe can afford to buy a motorcycle or small car, at least take a loan out on one. The composites wouldn't make that big of a difference in the cost of a vehicle.

A composite is heavier than plasic but lighter than tin. It is also stronger by unit weight than steel. So there's really no downfall to using composites. Plastics would be cheaper and lighter while providing the same protection of zero that today's tin siding.

We've discussed the general history of things before. BMW made engines for airplanes for many years. But they started using them in their cars. The rotary enginges used in airplaines for decades are now being used in some Mazdas. They are very good engines. We'll see if they expand further into the market, and I'm not sure of the maintenance costs.

I read quite a few of the studies concerning composites vs metal, cost being a factor. I saw that in the late 70's to early 80's, the DOD started doing research on how to use composite materials in various things ranging from portable Army bunkers, to complete construction in Naval ships. Even in the 80's reports, during R&D phase, stated that the cost of composites were 3.3x that of the aluminum counterparts but the costs are "greatly overestimated... production is allowing for rapid reduction in cost of composite materials."(some army cost report)
Composites are also currently being used in aerospace testing and to put small satellites in orbit. They use composites because the roughly 10% increase in constuction cost today greatly reduces the weight and allows for better resistance to heat and stress. So for a car, give up the $2000 convenience package for composite-infused alloys and you don't pay any more for the car but you save more in fuel without sacrificing safety or strength.

All of the more current reports stated that composites on a mass-production basis could be equal or slightly higher in cost when compared to metal or plastic, but provide many benefits like strength and protection against catastrophic material failure.

Here's a link to the space one

http://www.ce.utexas.edu/em2000/papers/EFosness.pdf


You would think it'd be a win-win. Maybe it is, and it's just a matter of time. I'm leaning toward that angle. But we will know if/when composites are more widely used in cars.

It appears Mazda was able to convert their "rotary" engine over to hydrogen burn cycle. Surprising since the burn characteristic would seem to indicate this would be difficult. I can only guess hydrogen does well with turbo charging.