I love it when you guys get all techie!

Cost vs benefit per given application, correct?  I've purchased my WBX with
a stainless exhaust from a gentleman who lives in Canada where such a system
makes perfect sense.  Obviously the gentle Atlanta climate, where I live,
makes stainless steel exhaust seem extravagant and unnecessary, but damn, it
sure is pretty to look at!  I think I'll keep it.

Chris S.

On Tue, Jul 22, 2008 at 6:14 PM, Mike <mbucchino@charter.net> wrote:

>  Rust is a form of corrosion; corrosion is not neccessarily
> related only to rust (breakdown of a ferrous metal due oxidation).
>  I've held FAA Airframe & Powerplant mech licenses for 27 years, so I do
> have formal training and years of hands-on experience.  Aviation mechanics
> frequently replace stainless steel exhaust sytem components on aircraft due
> to corrosion, not rust.  The high temps and gas flow cause erosion of
> materal, eventually thinning things enough to cause a hole to blow out
> (usually on the bends where concentration is highest).  This corrosion
> process happens many years later than rusting would happen on a mild steel
> system, so the benefits of using an all-stainless system is obvious.
>  My question is;
>  How long does the average expensive OEM Vanagon mild steel system last,
> versus a very expensive aftermarket stainless Vanagon exhaust sytem, if all
> factors are the same?  The added cost of the stainless system must greatly
> outweigh the shorter life of the stock system.  How many stock set-ups
> would
> you have to replace, to equal the cost of the more expensive one?
> I'm not factoring in replacement labor here, just parts.
>
> Mike B.
>
> ---- Original Message -----
> From: "BenT Syncro" <syncro@GMAIL.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Tuesday, July 22, 2008 5:11 PM
> Subject: Re: The DEEP, DARK secret of fiberglass exhaust wrap discovered
>
>
>  On 7/22/08, Scott Daniel - Turbovans <scottdaniel@turbovans.com> wrote:
>>
>>
>>  stainless has a lot of properties that make it not as good as steel in
>> many applications.
>>
>> I just want to interject something. Stainless steel is still steel. You
>> must
>> mean mild or carbon steel.
>> As I understand it, stainless steel is nothing more than carbon steel with
>> some chromium added to
>> mix. As the chromium oxidizes, it forms a protective layer onto
>> the iron/steel in the alloy in a similar
>> way that zinc coated steel (galvanized) forms a protective layer over the
>> steel when the zinc turns
>> into zinc oxide. The difference, of course, is the chromium is
>> 'throughout'
>> the material. It's in the
>> alloy.  My best non-metal comparison I can think of are countertops. In
>> Corian (and similar types) the
>> coloring is throughout the material vs. laminated tops such as Formica
>> (and
>> similar types) which only
>> has coloring close to the surface. Corian would be similar in wear
>> characteristics as stainless steel.
>> Surface wears (chromium turns to chromium oxide) but it's still Corian
>> through and through. Formica
>> wears out (zinc in galvanized steel turns to zinc oxide) and eventually
>> the
>> material of the countertop
>> is no longer protected. Same case with the metals. Stainless steel just
>> keeps going in going but not
>> forever. Eventually the material gets thin enough and as some have pointed
>> out - rusts through.
>>
>> The amount of chromium content will determine at what rate the stainless
>> steel will deteriorate. Why not
>> dump more chromium in the mix? Well, chromium is not as strong as carbon
>> in
>> steel. The more chromium,
>> the weaker the material. Like anything else, it's a balancing act of
>> anti-corrosive properties vs. strength.
>> Which brings me to the Vanagon application. Vendors offer not just
>> different
>> alloys of stainless steel but
>> different gauge as well. Since there is no independent testing of the
>> durability of these products, it would
>> be good for someone to start tracking how well these commercially
>> available
>> systems are holding out. You
>> know... more chromium wears longer from a corrosion point of view. But
>> they
>> wear faster as in from cracks
>> due to metal fatigue, etc.
>>
>> Aw, what do I know. I'm no metallurgist. English isn't even my first
>> language. Steel, steal, sounds the same
>> to me.
>>
>>
>>
>> BenT  P. Ipez
>>
>