Underbody preparation

[Huw Powell]

George Harris wrote:
> But the reason for the email is; Does anyone have any suggestions for
> preparing the underbody for the second life of this auto?

> How about just stripping and patching the rusty areas?
>
> It does look pretty sound for a 15 year old car.

As one lister already pointed out, the underbody protection on Audis by
the mid to late eighties is that super tough, thick, rubbery "good
forever" stuff.  My local Audi dealer told me what they use (one of two
products?) and that it uses a special spray gun to apply.  I wanted to
use it on my truck, if I ever get the body rebuilt for it...  3M 08874
and 08949 were the numbers given to me for the "stuff."

I bet you could brush it on to smaller areas, but I've never tried.

Anyway, your car came from the factory with galvanised steel body
panels.  You try to be careful NOT to remove coatings down to the bare
metal where it is still good, as you may just remove some of the zinc.

In places where you have rust, it is probably surface only, since the
zinc elsewhere still acts as a galvanic corrosion protector (my 90Q has
some of this "surface browning," which never seems to get any worse).

I think they told me to put the rubbery stuff on *after* priming and
painting.

So go easy, gently remove any rust you do find, sand (or "media")
blasting is the best way to completely remove it (as much as possible),
a wire brush won't get inot any pits.   Then prime it, paint it and add
whatever you can get or work with as a sealer/protectant.

For components that are completely removed, and don't have any rubber
bits built in (like subframes, control arms, etc. depending on the car),
getting them media blasted and powder coated makes a very durable long
lasting finish, if you can get it done without spending a fortune.

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/