Date: Wed, 6 Mar 96 22:19:22 EST
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: jag@cs.rochester.edu
Subject: Re: Rusting seams and other hard to fix rust problems.
Steve Johnson <sjohnson@pcocd2.intel.com> writes:
> So how does Bob H's sermon compare to the FAQ: Rustoration written by
> Ed Delaney? Personally, I believe that two nice references are better
> than one. I guess I should read them both, but I'm definitely out of
> my league here. I'm sure Thom Fitzpatrick will lead me down the path
> of rust-free righteousness. ;)
>From Bob's rusty seams sermon:
When dealing with a rusty seam often times your only recourse is to
use chemicals but the most successful method is to remove the rust,
weld the seam closed and go on from there.
>From vwairfaq:
So basically you have rusted metal. You can cover it up by
cleaning off the rust, coating it with some rust inhibitor, cover it
with body filler, paint it and wait for the rust to reappear some
other day. There are those that feel this is adequate given a tight
budget. The more aggressive types say you should always cut
out *all* rust, replace with new metal, grind, sand, prime and
paint for a long lasting solution. This FAQ will assume you want
to be a little more aggressive and do a thorough job, but will
mention the "low dough" approach when appropriate.
So basically both are bad news to us who think we can solve our problems
with a little sanding, naval jelly (phosphoric acid) and bondo. However
Bob's sermons does go on and tell us how to do a descent job without
welding.
>From Bob's how to fix the rusty windshield sermon:
(http://www.sky.net/~rmk/hoover/rustywindshield.html)
If you wish to use fiberglass for the repair you should
have some experience with composites and with
the unique problems of bonding composites to steel
structures. In most cases the fiberglass repair will
result in a new, rust-proof flange only to produce
rust under some other portion of the repair a few
years later. Repair of an improperly done composite
repair is more difficult than doing a welded repair.
The best composite repair is to build a mold of the
shape you wish to produce using rigid urethane
foam. You can glue the foam to the dashboard then
sand it to shape. This will put gravity on your side
as you do the lay-ups and fills. Covering the
urethane with heat-smoothed plastic sandwich
wrap will impart a glass-smooth surface to the
finished lay-up.
The lay-up should progress in two steps, first
laying up two or three layers of fine twill-woven
six-ounce fabric saturated with a suitable epoxy
resin. Surface with peel-ply and allow to cure. Strip
off the peel-ply. trim for height, lay in a build-up of
saturated chopped cotton fiber to form the fillet then
do the finish lay-up with two or three layers, the
first layer being the widest, the other(s) narrower.
The stepped layers will be easier to blend in to the
contour. If properly done, the repaired flange will
have exactly the same contour as the metal flange it
replaced but will be stronger and impervious to rust.
Once the lay-up has cured, grind to finished size
and blend the layers into the contours of the nose.
Prime and paint.
/Martin
PS Have you noticed how easy it is to follow inlined hyperlinks
when reading the vanagon@lenti list from Skips WWW page
(http://www.automatrix.com/~skip/volkswagen/vanagon-list/)
Just click on the link and you're there. Technology always
amazes me.