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  #1  
Old 06-10-2011, 03:39 PM
ralph124c ralph124c is offline
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Do Fiberglass Body Cars Outlast Steel Bodied Cars?

As far as I know , the only production cars (using fiberglass bodies) made in the USA were the Studebaker Avanti (1961-63), and the Corvett sports car (fiberglass Corvettes were made at various times).
Sice fibreglass-reinforced plastics don't rust, one would thing such cars should have an indefinite life.
Indeed, most fiberglass cars look pretty good-provided they are kept in good repair.
A steel body car (if properly painted and rustproofed) can last 30-40 years (in places like Southern California-less in wintry places where salt is used on the roads).
So, if I bought a nice Avanti, could I keep it forever?
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  #2  
Old 06-10-2011, 10:28 PM
GameHat GameHat is offline
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Originally Posted by ralph124c View Post
As far as I know , the only production cars (using fiberglass bodies) made in the USA were the Studebaker Avanti (1961-63), and the Corvett sports car (fiberglass Corvettes were made at various times).
Sice fibreglass-reinforced plastics don't rust, one would thing such cars should have an indefinite life.
Indeed, most fiberglass cars look pretty good-provided they are kept in good repair.
A steel body car (if properly painted and rustproofed) can last 30-40 years (in places like Southern California-less in wintry places where salt is used on the roads).
So, if I bought a nice Avanti, could I keep it forever?
Speaking as an engineer in the plastics industry (I make the plastic in fiberglass) I can say I can't imagine any plastic made in the 60s lasting forever.

Fiberglass does corrode. It doesn't rust, but it is attacked by water, salt, etc. There is fiberglass that is corrosion-resistant, but I can't imagine a car in 60s being made out of this.

We supply a lot of customers right now that make truck, RV and mass-transport fiberglass parts (body panels, etc.) And I know these don't last forever.

So no, they won't last forever.

Last edited by GameHat; 06-10-2011 at 10:29 PM..
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  #3  
Old 06-10-2011, 10:40 PM
Omniscient Omniscient is offline
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You seem to be implying that the body is what fails on cars causing them to lave the road. Very few cars are scrapped because the body rusts or otherwise deteriorates. Cars are scrapped because the transmission fails and/or the engine fails. Whether the body panels are fiberglass, carbon fiber, plastic or steel the engine and transmission are all going to be made of the same things.
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Old 06-10-2011, 10:43 PM
GameHat GameHat is offline
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sorry, missed the edit.

Another thing - you're sort of drawing the wrong conclusion to the question "why make vehicles out of composite materials?"

The primary reason to make vehicle parts from composite materials isn't longevity. The main advantage (in vehicles) that fiberglass and carbon-fiber parts have is that composites have a much higher specific strength.

Meaning - if you have certain mechanical requirements of a vehicle part - composites can meet the same mechanical requirements of steel but at a much lower weight. This is important for performance and/or fuel economy. The downside is that they tend to be more expensive and difficult to fabricate.

Composites used in transportation can have a much longer life, but modern steel/aluminum + corrosion resistant coatings make the longevity thing kinda moot for transportation. You'll need a new engine, transmission, etc. long before a modern vehicle rusts out.

//And sorry, Omniscient made the point before this, and is correct. Missed while typing!

Last edited by GameHat; 06-10-2011 at 10:45 PM..
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  #5  
Old 06-10-2011, 10:51 PM
jz78817 jz78817 is offline
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Cars are scrapped because the transmission fails and/or the engine fails.
maybe sometimes, but cars generally get scrapped once they start nickel-and-diming the owner. e.g. $500 for struts, then three weeks later it needs $800 for engine mounts and control arm bushings, then a couple months later it needs a heater core, etc.

only a simpleton thinks the engine and trans are the only costly parts of a car.
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Old 06-10-2011, 10:59 PM
Omniscient Omniscient is offline
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Originally Posted by jz78817 View Post
maybe sometimes, but cars generally get scrapped once they start nickel-and-diming the owner. e.g. $500 for struts, then three weeks later it needs $800 for engine mounts and control arm bushings, then a couple months later it needs a heater core, etc.

only a simpleton thinks the engine and trans are the only costly parts of a car.
No, cars get sold or donated when that happens. Cars that run almost always stay on the road one way or another. There's a reason the Cash For Clunkers program mandated that the engines be run with sand in them to destroy them after they were traded in. Cars get scrapped when the engine or transmission needs to be replaced or rebuilt and that costs far more than the car is worth. A car with bad brakes, no AC, a failed heater core etc. get driven by people too cheap or indifferent to care to fix them. If you "scrap" a car that simply needs new engine mounts of control arm bushings it'll end up at a car auction and sold to a used car dealer or buyer looking for a really cheap car.
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  #7  
Old 06-11-2011, 01:20 AM
Blackhawk441 Blackhawk441 is offline
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A neighbor of mine kept a late '50s Corvette up on blocks for forty-some-odd years before just recently restoring it and putting it back on the road.
WAG that in a situation like that, fiberglass would outlast steel (because humidity probably has less of an effect on fiberglass in a controlled environment), but it would probably be different on the road.
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  #8  
Old 06-11-2011, 01:34 PM
GreasyJack GreasyJack is online now
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Originally Posted by Omniscient View Post
No, cars get sold or donated when that happens. Cars that run almost always stay on the road one way or another. There's a reason the Cash For Clunkers program mandated that the engines be run with sand in them to destroy them after they were traded in. Cars get scrapped when the engine or transmission needs to be replaced or rebuilt and that costs far more than the car is worth. A car with bad brakes, no AC, a failed heater core etc. get driven by people too cheap or indifferent to care to fix them. If you "scrap" a car that simply needs new engine mounts of control arm bushings it'll end up at a car auction and sold to a used car dealer or buyer looking for a really cheap car.
This is generally not true. Unless they're something unusually nice for a donation, almost all the cars donated to charities go straight to the junkyard. The trouble is that you can buy a generally nice car for under $1000 so nobody is going to want a car where someone has neglected a bunch of nickle-and-dime problems that add up to well over $1000. Even something like a clutch or a scheduled timing belt change can "total" a very old car. Used car dealers especially want cars they can turn around and sell, not repair projects. Private car buyers who buy such cars are usually after them for parts too. One exception is that certain models might be desirable for export to other countries. But I think in general it is safe to say donating a car with many problems to charity or selling it for some paltry sum in the classifieds is synonymous with scrapping it.

The engine or transmission being the weak link longevity-wise was certainly true back in the days of the Avanti and the older Corvettes, but these days unless you never change your oil or timing belt or if you overheat the engine, engine and transmission failures remain quite rare even past the point that the rest of the car is pretty well beat. Back in the bad old days, this did often mean when the body or frame rusted out. In some parts of the rust belt, even when you could only expect less than 100,000 miles out of a drivetrain, some cars still rusted out first! This was especially bad with early Japanese cars, because their engines lasted much longer but they rusted just as bad if not worse than domestics. It's only in the past 15 years or so that they really "solved" the rust problem.

So, as a roundabout answer to the OP, in many climates Avantis and Corvettes (or Deloreans) would keep looking nice quite a lot longer. (I had a friend who bought a 78-ish Corvette for $500 around 1990 and it looked a helluva lot better than any other "survivors" on the road from that vintage.) In some particularly severe climates, this might have even translate to them "lasting" longer. But these days, the problem of rust in steel-bodied cars has largely been solved, so fiberglass bodied cars would be solving a problem which no longer exists.
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  #9  
Old 06-11-2011, 01:52 PM
engineer_comp_geek engineer_comp_geek is offline
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I have a kit car which is essentially a 1960 Beetle with a fiberglass body that makes it look like a 1929 Mercedes. I have to take care of the Beetle parts so that the bottom doesn't rust out, but I don't have to worry about the body at all. Body rust is very often a problem on older cars, so in this case there is definitely something to the OP.

The fiberglass conversion on this car was done sometime in the 70s, and the fiberglass body has faded somewhat over the years. So while the OP's Avanti may not rust, it will eventually fade and need a new paint job.
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Old 06-11-2011, 04:41 PM
Omniscient Omniscient is offline
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It's worth noting that fiberglass has a secondary issue in that it's not as useful from a safety perspective. It doesn't absorb impact energy in the way that steel and to some degree carbon fiber does.

Quote:
Originally Posted by GreasyJack View Post
This is generally not true. Unless they're something unusually nice for a donation, almost all the cars donated to charities go straight to the junkyard. The trouble is that you can buy a generally nice car for under $1000 so nobody is going to want a car where someone has neglected a bunch of nickle-and-dime problems that add up to well over $1000. Even something like a clutch or a scheduled timing belt change can "total" a very old car. Used car dealers especially want cars they can turn around and sell, not repair projects. Private car buyers who buy such cars are usually after them for parts too. One exception is that certain models might be desirable for export to other countries. But I think in general it is safe to say donating a car with many problems to charity or selling it for some paltry sum in the classifieds is synonymous with scrapping it.

The engine or transmission being the weak link longevity-wise was certainly true back in the days of the Avanti and the older Corvettes, but these days unless you never change your oil or timing belt or if you overheat the engine, engine and transmission failures remain quite rare even past the point that the rest of the car is pretty well beat. Back in the bad old days, this did often mean when the body or frame rusted out. In some parts of the rust belt, even when you could only expect less than 100,000 miles out of a drivetrain, some cars still rusted out first! This was especially bad with early Japanese cars, because their engines lasted much longer but they rusted just as bad if not worse than domestics. It's only in the past 15 years or so that they really "solved" the rust problem.
When a car that runs is donated it's always auctioned. Almost without exception. Cars that are donated and don't run are also often auctioned, but sometimes just scrapped immediately. What the buyer at that auction does with the car is difficult to generalize, but if the car runs the odds are very good that it's going to be sold and back on the road. Some makes are more valuable as parts, especially imports, because parts are scarce but generally speaking a car that drives will at least get an attempt to sell.

Car owners don't want to invest $1000 in nickel and dime repairs to a beater, but used car lots will because they have salaried mechanics who do the work for cheap. Most of those "nickel and dime" repairs are cheap parts that require expensive labor. Used car lots specialize in replacing timing belts which are essentially free compared to the labor involved.

Remember how auctions work. Usually car buyers don't get an opportunity to examine the cars prior to purchase aside from a brief visual inspection. If the car runs and is able to drive up to the podium it's likely to get bid on. If a buyer sinks $500 into a car only to find that it needs a new clutch, they are going to have their guy toss a new clutch in there and try and recover their investment. They aren't just going to toss up their hands and say "aw shucks" and scrap it. In some cases the issue add up to more than it's worth to patch up to sell, but most often they will get a try.

I suspect people are biased by what they see on your typical suburban used car lot and/or dealer's pre-owned lot. Those places tend to have high standards. Visit the inner city and you'll see where all those really beat up cars that still run are being sold.
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  #11  
Old 06-12-2011, 12:11 AM
astro astro is offline
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Here's a discussion of fiberglass life expectancy and deterioration issues. Although the discussion is about boat construction it should apply to all fiberglass structures.

Life expectancy of fiberglass?

Last edited by astro; 06-12-2011 at 12:12 AM..
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  #12  
Old 06-12-2011, 09:48 PM
Balthisar Balthisar is offline
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Almost all modern cars are unibody, i.e., their structures are the body. You can't build meaningful structure from fiberglass. You could make some of the exterior surface panels from non-metal materials (Saturn did that for a long while), but the rest of the structure is still subject to rusting.

Anyway, the jury's still out on modern cars. There're are a lot more galvanized parts, and e-coat, and proper draining, and better paints. When I was a kid, everything was a rust bucket in a few years. I just sold my 10 year old car without a single spot of rust anywhere on it, and this is salty Michigan.
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Old 06-12-2011, 10:00 PM
jz78817 jz78817 is offline
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Originally Posted by Balthisar View Post
Almost all modern cars are unibody, i.e., their structures are the body. You can't build meaningful structure from fiberglass. You could make some of the exterior surface panels from non-metal materials (Saturn did that for a long while), but the rest of the structure is still subject to rusting.

Anyway, the jury's still out on modern cars. There're are a lot more galvanized parts, and e-coat, and proper draining, and better paints. When I was a kid, everything was a rust bucket in a few years. I just sold my 10 year old car without a single spot of rust anywhere on it, and this is salty Michigan.
my dad has a 21-year old Dodge Spirit (also in michigan) and the only visible rust is a few spots where the paint was gouged through to bare metal.
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  #14  
Old 06-13-2011, 03:34 AM
Omniscient Omniscient is offline
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Originally Posted by jz78817 View Post
my dad has a 21-year old Dodge Spirit (also in michigan) and the only visible rust is a few spots where the paint was gouged through to bare metal.
Of course my 11 year old Oldsmobile has been a rusted out piece of shit for going on 7 years now.
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