Even
in areas where road salt is not used, rusting agents may be present
which literally eat holes in automobiles. Dilute sulfuric acid is
present in many areas in the highly publicized form of 'acid rain'.
Some crop spraying chemicals are also active rusting agents, while salt
spray in coastal areas often turns cars into dangerous hulks of rusty
steel lace. Once the rusting process has begun (often by the time the
car reaches the dealer), it is too late for protection - remedial
action must be taken immediately to remove existing rust, no matter how
seemingly insignificant.
The
only way to remove rust which hasn't yet eaten entirely through its 'host' panel is to sand down to clean metal, treat the sanded area with
a rust remover (most proprietary solutions containing phosphoric acid
work well), wash thoroughly to remove all traces of the rust remover,
prime and paint. It's a lot of work, even for a relatively small area.
If rust is forming between two pieces of metal spot-welded together, or
otherwise lapped over each other, acid treatment is not recommended, as
it can't be adequately neutralized.
What
can be done to de-rust a sealed, boxed-in area? Unless you can get to
all rust-contaminated surfaces and derust them, there' s not much that
can be done. Generally, the compounds advertised as 'rust neutralizers'
and such, have some rust retardant value, but they don't seem to effect
permanent cures.
'Body
cancer' is one of the least pleasing pseudonyms of automotive rust, but
one of the most accurate. Once rust has eaten through a panel, even in
pin-holes, the only cure is to cut out the affected part and weld in a
new piece. This can be more trouble and certainly more expensive than
prevention or immediate first aid when rust is first noticed, but it is
the only way to cure the problem. Body-putty, lead, pop-riveted patches
and other commonly used ' repair' methods only hide the problem, they
do not cure it.
Rust
has an even more dangerous cousin electrolytic corrosion of aluminum
panels where they join steel as on Big Healeys. In this case, the
aluminum and steel, in the presence of moisture, act as an electric
battery, especially when the moisture is salt-laden and the temperature
is warm. When this occurs, the aluminum crumbles and turns into white
powder, leaving the steel rusty, but usually sound. What makes this
form of 'body rot' worse than rust is that it is much more difficult to
perform 'cut and weld' repairs on aluminum than on steel.
Prevention
of corrosion is much easier than repair. When washing your car, wash it
thoroughly underneath as well. Do whatever you can to dry it - blow
with compressed air, mop it dry, or open doors, trunk and hood to allow
water to evaporate. Letting it sit out in the hot sun will dry it
quickly enough. Above all, do not put a wet car in a heated garage -
heat, combined with high humidity, is what rust thrives on. Check the
car thoroughly underneath for raw or rusty metal areas- clean and
protect them with paint, undercoating, or even grease. Have you ever
noticed that the bottoms of your front floors never seem to get rusty-
the oil from engine leaks protects them. (This won't prevent floors
from rusting from the inside, though.) Do whatever you can to prevent
rust from starting. Most commercial undercoatings work very well when
properly applied.
Checking
a car for rust and finding all the rust is not as easy as it sounds.
For example, by the time rust bubbles appear under the point at the
lower front of MGB rear fenders, it' s a good bet that at least the
rear portion of the rocker panel (covered by the fender) and the
vertical inner sill panel are in much worse condition. The only way to
find this dangerous structural rust is to explore. Remove the outer
rusted fender section, probe deeply and try not to be horrified by what
is found. On most cars, removal of the front bulkhead sealer plates
will show if there is any rust 'inside' the lower rear of the front
fenders. This is one of rust's favorite spots. While exploring, the
traditional 'ice pick' method works, but I prefer to tap suspect areas
with a body pick hammer which has the pick ground to a hemisphere about
l/8" in diameter. Light tapping with this won't damage sound bodywork,
but it will, by sound and feel, if not by penetration, find all rust
damaged areas which are not usually apparent.
So
your car's like mine, well past the prevention stage, and ready for
major surgery. Moss helps hundreds of us each year by supplying not
only complete fenders, rocker panels, and floor boards, but also repair
panels which are designed to replace those areas of your car which are
prone to rusting. Check the Moss Catalog for the car of your choice and
you will likely be surprised by the number of such body repair pieces
available.
Eric Wilhelm, Moss Motors Staff