Hello Mike,
I've given the problem of those rear lower quarters quite a bit of
thought since I completely replaced them on one of my cars and
welding in a bit of new metal on my other car within the past year.
The problem with completely filling the quarters is that it's
difficult to get the bond between the different materials to hold
over time. Different expansion characteristics and the general
shrinkage of most plastic like materials eventually will break the
bond between materials and allow moisture to collect and rust to
begin.
A coating rather than a solid filler allows the materials to hold
together better but coating the lower areas of late model cars, with
lips, is a tricky matter.
I came up with a solution that, for me, is working quite well. I
filled the rear quarters with the same high solids, two part epoxy
paint (the manufacturer calls it "mastic") that I used on the inside
of the car BUT, after sloshing the paint around a few seconds, I used
a vacuum pump arrangement to suck out extra paint which leaves a
solid coating all through that area, including inside the lip area.
I can't use that same system along the top of the rear wheel wells so
I spray thinned Waxoil into those areas. These areas essentially
can't be seen or touched and I think the Waxoil will provide enough
protection there.
When I come home from a swim, I run a folded paper towel down into
those rear quarters to suck out any water splash that might have
accumulated but I think that even if I didn't do this, the coating
itself forms enough of a "bathtub" so that the water would eventually
evaporate without causing trouble.
I live in Southern California, where it rarely rains, so my cars have
it a bit easier than they do in many places. My solution works
pretty well for me but I realize that if the car were left out in the
rain, those rear quarters would probably fill up and I wouldn't want
that to happen on a regular basis. I've tried to come up with a
solution that would perhaps work better for those folks in climates
not as dry as mine.
My current thoughts involve coating those lower quarter areas, like I
do now, and then filling them with that expansion foam used in the
building trades. A bead of it layed down at the bottom of the
quarter would expand right over the top and should completely fill
the space. I would then slice off the part that comes above the
floor edge and top coat the exposed, open foam with a couple coats of
the same epoxy interior paint. This would fill the holes in the foam
and seal out moisture. That foam stuff sticks like crazy and it
should remain flexible enough to "give" a bit with the expansion and
contractions of the various materials. Also, if you had to, you
could get much or all of the stuff out without chopping away the
quarter panel.
I'm not a big fan of the drain idea, mainly because I'd probably
forget to close of the drains someday. Also, I don't think a drain
could easily be put right at the bottom of the cavity.
My cars run essentially "dry" so I was surprised when I had problems
with one of my cars rusting in the lower quarters even though nothing
got into the car. It turned out the problem was that during some
previous repair of that area not enough care was taken to close off
the bottom seam between the inner and outer panels. Water was
getting between those layers and causing the rust. I never had water
in the car because the inner coating was keeping the water out.
Since figuring this out, I now examine those lower seams each year to
be sure they are tight. If any sign of a crack shows up, I close it
off with a rubberized version of superglue which I find at a local
hobby shop. Only use it if you find the rubberized type though since
most superglues are so brittle that I think they would crack over
time.
On a related issue. I did an article about a year or so ago about
hidden rust in the frame rails. It was posted as a tech column in
the newsletter and I would suggest you look it up for my thoughts
there. Basically, I open a 1" inspection hole on the top center of
the frame rail, several inches in front of the transmission mount.
This hole allows for the removal of accumulated water and also lets
the hot engine air circulate inside the frames to dry out
condensation. All four rails, in both my cars, either had standing
water or signs of previous water in them. If your car runs "wet" you
can simply use rubber stoppers, from the hardware store, to close off
those holes when in the water. I also put in emergency drain plugs
up near the steering gear but I've never had to use them.
P.S. Even though it's hard for me to get to Celina, and I've only
been there once, I think the convention should stay there. That
great town and it's people would be hard to beat or even match.
Enjoy,
John Friese
Santa Barbara, CA
67 White
67 Red
--- In amphicar-lovers@yahoogroups.com, "Mike Israel"
<amphicar770@y...> wrote:
> Hi All,
>
> Amongst the many late night discussions at Celina was the topic of
> how best to deal with the rear quarters in that pocket between the
> inner and outer panels. Would be interested in thoughts and
> experiences of others.
>
> There seem to be three options with pros and cons to each.
>
> 1) Fill them with epoxy or something. The advantage here is that
> if you can keep water out then you should have no future problems
> with rust. The problems seem two-fold. If the seal is broken due
> to vibration or anything else, water will definitely be trapped
with
> no way out other that to eventually start oxidizing metal.
> Likewise, if the space is filled, it would make doing a spot repair
> more difficult as you could not just easily cut out a coin sized
> piece and weld in a patch.
>
> 2) Leave them open. Water will get in there and how do you then
> fully dry it out? At the same time, easy to keep an eye on what is
> happening and you can use maintenance treatments such as waxoil.
>
> 3) Leave them open but put some sort of small drain plug at bottom
> of each panel. Not sure on pros or cons here?
>
> Your thoughts?
>
> Mike I.
