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A seasonally-changeable disposable shrink-wrap is applied to the
underbody of a vehicle to provide protection from water, mud and
road salt, primarily during the winter season. Just like swapping on
winter tires, the winter underbody shrink wrap would be part of the
annual ritual of winter automotive
preparation. Heat shrinkage would
make the wrap taught and aerodynamic, to avoid flapping in the wind
while traveling at high velocity. An adhesive strip made of silica
aerogel foam would first be glued to the underside of the
exhaust/muffler, to provide a small air-gap separation between the
hot surface of the exhaust system and the shrink wrap. [see link
below to learn about aerogel]
aerogel thermal insulation in action [sanman, Oct 25 2020]
Full Underbody Shield
protective cover for full underbody of vehicle [sanman, Oct 26 2020]
||Salty water would collect between shrink wrap and metal, enhancing corrosion.
||The shrink wrap would hydrophobic, to repel water. It would
only be intended for use across a single winter season, before
being discarded. As a shrink wrap, it would be stretched tight
like a drumskin across the vehicle underbody, and not hugging
each and every surface contour like a coating would. An air
gap would therefore exist between the plastic wrap and most
of the vehicle underbody.
||The underside of a car is a complex structure that
features moving parts, as well as an exhaust that
gets very hot. The best way to treat it is to spray it
with something simple like sump oil. That's what
we used to do. Nowadays cars are better made and
the bottom less prone to rusting out. Of course I'm
not taking about American cars which are
complete rubbish in every way. I'm describing
properly made European, Japanese, or Korean
vehicles. The America ones probably do need cling
film to hold them together.
||I used to have an MG. It was a level of bad engineering
that I actually sort of respected. Like getting to be a pitcher
in the major leagues without being able to throw the ball
more than 3 feet. It's like "Wow! How did you get this job?
You actually must be pretty clever!". I think the electical
system was actually designed by squirrels, which again, I
sort of respect.
||kdf - rubberized undercoating can actually end up trapping
moisture and causing rust, since its ability to adhere to the
metal surface is imperfect. With the shrink wrap, there would
be an air gap between the wrap and the metal surface in
||I just posted another link for "Full Underbody Shield" which I
found while researching online. Maybe this could be a more
long-lasting solution. I'd imagine you'd want these things to
be replaceable every 50K(?) miles. Just as we have floormats
to protect the carpeting in our cars, maybe we could have an
underbody mat made from corrugated rubber, and it would be
cheap enough that you can replace it every once in awhile.
||Yes, sump oil and other types of grease can form a coating
and self-seal any gaps. But the problem is that in snowy
places, you can be traveling over snow, and it will be
brushing up against the underside of your car, and it will
scrap off large sections of your greasy undercoat, which
results in the loss of that coat and its protection.
||Ever traveled in snowy weather, and trucks other big
vehicles are pushing the snow and slush around under their
big tires, to literally pile it up in places? You'll travel over
those piles, and you'll hear it scraping the underside of your
car. What's your greasy/waxy undercoat doing to do against
that? Most people don't have a hoist/lift at home, to be able
to reapply the grease/wax undercoat every time they've
driven over a snow drift.
||If the car itself is made out of plastic, then no need
for plastic coating.
||Composites are too expensive, and also lack general strength
beyond specific directional orientations. Regarding plastics,
remember GM's Saturn? I remember the plastic doors on the
early models used to warp on hot days.
||Make the car entirely out of shrink-wrap!
||In fairness, the ones produced in the 60s and to
some extent in the 70s had a unique individuality
and style. Since then the trend towards giant ugly
4x4s has resulted in the worst kind of rubbish.
Hondas are indeed very well made cars, though as
dull as dishwater.
||//I used to have an MG. It was a level of bad engineering
that I actually sort of respected. Like getting to be a
pitcher in the major leagues without being able to throw
the ball more than 3 feet. It's like "Wow! How did you get
this job? You actually must be pretty clever!". I think the
electical system was actually designed by squirrels, which
again, I sort of respect.//
||It is pretty impressive. Any particular MG, a B I guess?
What's also impressive is that they could still sell them in
the late 70's, even resurrecting the bodyshell in the late
80's. I'd not single them, or even British cars of the era
out though. French & Italian stuff of the era was just as
//the ones produced in the 60s and to some extent in the
70s had a unique individuality and style.//
||A few other things too. Given the environment, that is
the USA with half the current population, big distances of
arrow-straight roads, they produced some cars that fit
their niches quite well. It's possibly the remarkable lack
of individuality in the mechanicals that generated some
good cars. Most things through 1940's-1970's was a
variation on the same engine, trans & axle, medium/large
cars and light trucks included. Take a 1st gen Camero, V8
up front, turbo-350 3 speed in the middle and a 12-bolt
rear end with an Eaton locker. With 11:1 compression,
that's a fairly efficient 300bhp, that's totally drive-able
||Where it went wrong was the response to the emissions
legislation. Or maybe the heavy-handed nature of that
legislation from '70 onward. Low compression ratios saw
horsepower & fuel economy plummet to globally
embarrassing levels. The cars were still heavy, new
complexity was creeping in, build quality wan't