Aluminum Frame Problems for us Northern Folk...
 

Okay, I need an aluminum expert to tell me that it is in fact fdifferent... Now, I only drive my current Z in fair weather, however, occasionaly late fall, even well into the winter, we get som 60+ degree weather - and the Vette NEEDS to come out to play. I know how road salt eats aluminum... So if I go this route, my driving days become a mere 6 month window here in the north- assumning this aluminum frame has the same properties as, well, your everyday aluminum... :(

Audi's all weather AWD A8 has been all aluminum space frame for 7 years, as is the new Jag XJ and Ferrari 360/F430 and 612.

Add to this list the Ford GT, Lambo Gallardo and the Acura NSX which appeared way back in 1990......

Nature has provided aluminum with a highly protective “skin” in
the form of a clear barrier oxide on its surface that forms quickly and
is tough enough to hinder the deeper intrusion of oxygen and
other gases and liquids to the subsurface aluminum atoms. This
oxide is tightly chemically bound to the underlying surface, and if
damaged, reforms immediately in most environments. On a freshly
abraded surface, the barrier oxide film is only 1 nm thick, but is highly effective in protecting the aluminum.

The oxide film develops slowly in normal atmospheres to greater
thicknesses, and when corrosive environments are present, the
oxide may both thicken and darken. However, it generally
retains its protective character. Thus, in normal environmental
exposure, aluminum does not corrode (rust) away as does steel.
Aluminum surfaces do oxidize when exposed to air, but this
differs from the oxidation of steel in two important ways:
Aluminum oxide is effectively transparent and invisible to the
unaided eye. Aluminum oxide clings tightly to the surface of aluminum and forms a protective film that blocks progressive deterioration.
It does not flake off, thereby exposing fresh surfaces to further oxidation. When damaged, it quickly reforms again, providing continuing
protection.

With this natural corrosion resistance, the aluminum bodies
of many commercial motor vehicles, rail cars and aircraft are
unpainted; aluminum has proven durability in such applications.


Coatings:

Anodizing:
Anodic coatings are among the most useful for many applications
because they:

Increase corrosion resistance.
Increase paint adhesion.
Increase adhesive bond durability.
Improve decorative appearance.
Increase abrasion resistance.

The basic approach in anodizing is to increase the thickness of the
natural oxide coating on aluminum by converting more of the
underlying aluminum surface to aluminum oxide while the part
being anodized is the anode in an electrolytic cell.

Chemical Conversion:
Chemical conversion coatings are adherent surface layers of lowsolubility metal oxide, phosphate, or chromate compounds produced
by the reaction of suitable reagents with the metal surface. They differ
from anodic coatings in that conversion coatings are formed by
a chemical oxidation-reduction reaction at the aluminum surface,
whereas anodic coatings are formed by an electrolytic reaction.

Painting:
Same as steel.


I had to take an SAE course on corrosion during a job where corrosion was causing major failures. So I just copied this out of the instruction manual. :D

Wow thanks for that class!!!!! :thumbs:

Fabulous

http://www.autoaluminum.org/corpub.pdf (The source of the previous lecture)
http://www.autoaluminum.org/reppub.pdf
http://www.autoaluminum.org/frame.htm

When the A8 was first introduced a few years back - only one body shop in all of California was certified by Audi to repair the aluminum frame after a wreck. !

GM will void the corrosion warranty if they determine the car was ever driven on a wet road. ;)

Duke

Corvettes since '84 have used quite a bit of aluminum in their construction, the whole rear section of frame and bumper support in the C4's, as well as almost all the suspension pieces,and northern state salt corrosion hasn't been a bit concern. The big problem is corrosion caused by dissimilar metal's electrolysis in the presence of moisture and salt. Note how many late '70's Oldsmobiles you have seen with bumpers falling off, they were using aluminum for the 5mph bumper support, without a proper insulation between the bumper shock mount and the aluminum bumper support. Hopefully the technology that has been developed to produce all the above mentioned cars(Jags and such) will be used to advantage in the new Z06.

I think I'd be more worried about Magnesium Chloride than some rock salt. :)

Thanks Mighty-Mouse!

Why in the name of god would you drive a vette in the Snow / Bad weather.
These cars DO NOT belong in these conditions!

The mag chloride solution used by several states right now is much less reactive than salts used. Mag chloride should be used over salt in almost all situations, but there is some issue of possibly coating insulating materials and making them conductive.

Todd

The 5000 series of alluminum alloys (alluminium/magneseium) are used in boats for use in salt water with no problems. Don't worry about the frame, besides all the manufacturers have a "structural" corrosion test which is truely severe.
CBGPE

Well, if you're going to race on a frozen lake how else do you get there? :rofl:

I think we should be more worried here in Texas where they put enough sand on the road if it gets down to 33F that you'd be constantly sandblasting away the native oxide on your frame and nanometer by nanometer it would be slowly eroding away.

If I get one I'll probably just pay the dealer the $2000 for the 'underbody treatment' to avoid rust - since I'll also pay them for the 3M fabric treatment to avoid stains what's an extra few k?

:jester:

a. To get to work
b. TO go anywhere
c. It's a blast
d. It's still a car.
e. Why not?
f. Keeps them running all year round
g. It's a blast
h. Makes other drivers verrrry nervous and thus they tend to stay clear and slow down. Thus, I am contributing to the overall safety if the roads in my areas in the snow. :D
i. I use Zaino so snow/rain don't bother me when time for cleanup.

I would not worry about it. Drive it. To prove my point go look at the oldest C4 you can find that has been driven in the salt and check out all the aluminum suspension pieces.

Go live in Germany, that's 8 months out of the year!!!!