[DML] Re: undercoating

["David Teitelbaum" <jtrealty@xxxxxxxxxxx>]

Undercoating is used for 2 reasons. The obvious one, to try to prevent
premature rustouts, and the other less obvious is for sound control.
It adds mass to the panel and helps to prevent "drumming" while
reducing the passage of sound. Like adding Dynamat. Anyway
undercoating does help to lengthen the time required for the car to
dissolve. The probelm is nothing lasts forever. Eventually the
undercoating dries out, cracks, and moisture penetrates it to the base
metal. Now it traps the moisture and hides the damage until it is so
bad the undercoating comes off in chunks, like the epoxy paint. There
is no magic system that will last forever if you have mild steel
underneath. This is probably one of the reasons JZD had the molded
frame in mind origionally. He understood why cars wear out and was
trying to make a car that could last so long the owner would get tired
of it before it wore out. In that case you would go in for a "panel
job". In one day they would replace all the exterior panels for a
different color. Look at what happend to domestic cars produced in the
early 70's. Most had NO undercoating and many just rotted out so bad
you could see right through the fenders to the ground and all around
the wheel wells. The first big improvement was when the automakers
went to "Galvaneil". It was mild steel coated on one side with zinc.
That helped but the biggest improvement was when they started dipping
the cars and "electrocoated" them. That gets the zinc into all the
hidden spaces after all the welding. Undercoating is still used, just
a lot more sparingly. It adds weight which hurts fuel economy. On most
cars now the wheel wells are now plastic. Lighter and doesn't rot. The
holy grail now among automakers is to reduce the amount of steel and
use lighter composite or plastic parts. GEE, JZD did that over 20
years ago. I guess he was on to something, it was just that materiels
science was not up to the task at the time.
David Teitelbaum
vin 10757



--- In dmcnews@xxxxxxxxxxxxxxx, "content22207" <brobertson@xxxx> wrote:
> CLEANING the undercoating? You obviously have more spare time than I.
> 
> I own 5 Lincoln Mark V's. 4 of them came from the Northeast. 2 of them
> were undercoated with that black mess people use up there. Both of the
> undercoated cars suffered more road salt damage than the cars that
> were left without it:
>







To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/dmcnews/

<*> To unsubscribe from this group, send an email to:
    dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/