Because rust is such a problem for us, I thought it might be useful to
report some of my experience (gained from watching my cars disappear).
I had the dealer rustproof a new 71 Toyota Corona Mk II. The application
was very spotty. Where the coating was present, it protected the metal,
but there were more voids than coverage. The car rusted severely by the
time it was 4 years old.
On this same car, I tried to protect against rock chips by applying 3M
rubberized undercoating to the rocker panels. After 3 years, I noticed
the coating had some large blisters where it had separated from the metal.
These had held salty water against the body, and caused huge holes in the
rockers.
The next reasonably controlled experiment was a new 81 Toyota Corolla
sedan, which was rustproofed new by TuffCote-Dinol. This provided some
protection to exposed surfaces, but the second layer of this two layer
process was a tarry material that blocked the drain holes in the doors.
All four doors rusted severely, beginning within 3 years. Rust in the
doors was much more severe than in those of a friend's identical car that
was driven farther, left outside daily, and unrustproofed. On the whole,
I feel this treatment did more harm than good, but I have to admit that
the car (very rusty now) is for sale locally as a supposedly usable car
after 14 years and approximately 180,000 miles of salty roads. My
experience with trying to collect on the warranty convinced me that the
protection of the warranty is illusory at best. Even if a coating
completely fails to protect the car, you will not be likely to get back
even the original cost of the treatment. TuffCote is, I believe,
deservedly out of business in the US but I think still plugging drains in
England.
My 87 Prelude was waxoyled by the dealer when new. I bought the kit
described below, and reapplied waxoyl every 2 years. I periodically
squirted engine oil into drain holes in the body. I kept the car 7 years.
At the end of that time, there was a rust perforation on an inner fender
panel where the bumper attaches (missed application, I suspect) and some
rust starting in the seam between inner and outer rear fenders in just one
place. Other than this, the body was very well preserved.
I applied waxoyl myself to a new 89 Accord. It was in good condition
when traded after 5 years.
In between these others, I had a variety of cars including an elderly
Blazer that had been sprayed underneath annually with used engine oil.
The coating seemed extremely effective where it could remain in place,
but it was easy to wash off. My comments on oil treatment below.
When I was rebuilding Kermit the bugeye, I had almost every body cavity
open at one point or another, and could assess how best to protect it. I
drilled 1/2 inch holes for access before the car was reassembled, and
sprayed it with Waxoyl after it was painted (don't do it *before*
painting, unless you like grief).
I have an "undercoating system" from Eastwood, #2725 @ $43.95 for Waxoyl
application. You also need a plastic bottle or two, #2724A @ $1.95 each.
A kit of 1/2 inch plastic plugs, #2726 is $2.95 for a pack of 25. I don't
have an Eastwood catalog from Eastwood handy; I have one with a Sears
cover. The order # is 1-800-557-3277. The system requires an air
compressor, but a fairly small one will do. You will also need a 1/2 inch
sheet metal drill (a conventional bit will tear up the edges of the hole).
The kit comes with a long wand, a short wand, and a shortish wand on the
end of a plastic tube. Each will fit thru a 1/2 inch hole. There are a
variety of tips for the wands that give different spray patterns. I think
you have to play it by ear to decide what gives the appropriate coverage
in different places. For example, when spraying to cover the crevice
between the inner and outer rear fenders, I used a tip that sprays 90
degrees to one side. When using such tips, I put a bit of tape on the
wand so I could tell which way the tip was spraying inside the panel.
I also took some 1/8 inch welding rod and fastened it to the short wand
that is on a flexible tube, and that made a flexible but not floppy
wand. I could thread it entirely into structures like the rockers,
pushing the head way into the structure.
I thinned the waxoyl a bit with 40 or 50 wt motor oil for use inside
cavities, and used it straight on exposed surfaces. I heated it very hot
before application, by keeping the loosely capped can in front of an
infra-red type electric heater. Between applications, I laid the wand in
front of the heater to keep the material hot. I did try for direct spray
application, but having taken apart cars that were rustproofed, I know you
can't ever be sure of coverage by direct spray. The sight of mist
emerging in clouds 5 feet from the hole I am spraying into gives me a lot
more confidence I am getting protection, because the mist should cover
what I may miss directly. It is a good idea to repeat everything every
couple of years.
Someone said he or she taped up drain holes until the Waxoyl firmed up. I
think it is best, however, to let the Waxoyl drip out. Whatever comes out
is really excess; you only need and only want a thin layer. If you force
it to stay inside and solidify there, it may obstruct some of the drain
holes, and this does more harm than good. Water *will* get into body
cavities, and no amount of rustproofing will protect the body if the water
cannot get out.
I suspect that one can achieve much of the protection of Waxoyl for very
little money, if you simply squirt engine oil into the most rust prone
areas of your car. I have not rust proofed my new car. I may, but I may
also settle for just going around it every 6 mo or so with a squirt can of
oil. The wonderful thing about engine oil is that it creeps by
capillarity until it has permeated even very tight body seams like those
where door exterior panels wrap around the door frame. It will spread and
cover areas that never were sprayed directly. My experience with the
Blazer and the Prelude suggests that squirting a teaspoon of oil into a
door through the drip holes every 3 months will keep that door rust-free
indefinitely.
The only real drawbacks of oil are 1) that it washes off of areas that
receive direct spray, and will even wash out of panels that get a lot of
drainage. It is therefore useless under fenders or in panels that get
much drainage. It is good in doors, hoods and trunks, or in closed box
sections. 2) its tendency to creep causes it to appear on the outside
finish if a car is not washed often, and 3) if you spray it on exposed
surfaces you will have a car that is eventually very messy to work on. It
is not much fun to get under a car that has a half inch layer of
oil-impregnated dirt on it, but it helps a bit when you scrape that off
and find the frame still shiny beneath the grunge.
I am convinced that keeping body "rust traps" clear of debris and dirt and
judicious application of oil will dramatically reduce rusting. Waxoyl,
carefully applied, is good especially on older cars that had little
protection from the factory. The greatest benefits IMHO are that it does
not harden, resists spray, will stay on in areas that get a lot of
drainage, and does not plug drains if applied properly.
Classical undercoating, i.e. black tarry or rubberized material, has to be
used very cautiously, if at all. I sprayed a bit of rubberized
undercoating where gravel hits Kermit's inner fenders, but I keep a close
eye on it for any sign of deterioration.
My new appliance car is now receiving the benefit of the above distilled
experience as follows. I think new cars are fairly well protected from
the factory, which is comforting. I am damn sure not going to put
classical undercoating on it anywhere, because it is never going to
receive the attention Kermit gets to ensure the undercoating does not
lift. If I do anything, I will squirt oil into doors, the hood and trunk,
and box sections when the mood strikes and give it a home waxoyl
treatment. It is worth the $40 or so the materials will cost, and cannot
hurt. I ask at the car washes if they use fresh or recycled water, and
drive away if I'm not convinced the water is fresh. I hose off the
fenders and bottom occasionally. I apply a good polymer wax (Maguires)
every spring and fall, and watch like a hawk for rock chips. I also rest
easier knowing I have sandblaster, a welder, a spraygun, and the will to
use them if I prove to be mistaken.
There is a drawback to this equipment, though--it drives me a bit nuts
when I can't work on my own cars because my children and friends bring me
their cars to be rustproofed free, or worse yet, bring them for free
repair because they were too busy to bring them for free rustproofing.
Bah.
Of course, YMMV.
Ray Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
gibbons@northpole.med.uvm.edu (802) 656-8910
|