We
all know how much tires
and exterior trim that have that
satin glow
and are deep black in
color add to the visual impact of
our Ferrari.
However, the proper
techniques and products evade
most of us. We’ve
all seen tires
that look like a glazed doughnut
and paint streaked
with the dressing coming off the moldings.
And how many of you wish
your
dressing actually lasted longer
than a week? The other factor
in
the equation is the preservation
of the rubber itself.
Left alone, tires
and other exterior rubber will fade, crack and eventually lose their
mechanical properties through
Mother Nature. The first environmental
enemy of rubber is exposure to the ultraviolet (UV) light. UV
attacks
rubber through a process called photo-degradation (similar
to the way UV light oxidizes paint). The second enemy
degrading
tires and other synthetic rubber parts is ozone, a colorless gas
that is part of the air we breathe. When
ozone combines with UV
light, a reaction occurs that attacks the rubber polymers. Add
environmental pollutants
into the equation, and we have a problem;
“dry rot”. Dry rot is a million dollar concern for RV, boat trailer
and
classic car owners that are parked for extended periods (I’m
sure you’ve seen RV’s parked with their tires covered).
Early damage may be
seen as a general fading of the black color and eventual cracking of
the tire sidewall. To
protect against this environmental damage,
manufacturers add a stabilizer molecule called a “competitive
absorber”
to the tire polymer. It works by capturing and absorbing
UV radiation and converting it into heat to be dissipated.
All tire
manufacturers have been using the same competitive absorber, carbon
black (specially structured particles
of carbon), since 1904. Carbon
black is a reinforcing filler that is highly resistant to abrasion.
It is made from oil and
is the reason tires are black. While tires
could be made in designer colors (actually, rubber in its natural
state is light
gray in color), for various reasons including
consumer rejection, they are not common. Too bad, because I
remember
going to a Ferrari dealership when I was still in high school and
telling the salesman that when I finally
“made it” and bought my
yellow Ferrari, I would like forest green tires as an option. I
still remember the look he
gave me; priceless.
The competitive
absorbers are sacrificial, meaning they eventually get used up. As
carbon black loses its ability to
perform, the rubber turns gray.
This is one reason that black tires discolor as they age. To further
protect tires,
manufacturers add waxes and polymers into the tire
compound; this blend retards the ozone from attacking the
rubber and
extends the time before the tire starts to surface crack over a wide
range of temperatures. It’s no
surprise that caustic wheel cleaners
remove this protective coating, but an amazing number of rubber
dressings
also increase rubber deterioration. During a sidewall
inspection, manufacturers actually look for damage caused by
these
types of dressings. Tires flex when in motion, causing the wax
molecules to migrate toward the surface. This
forms a protective
barrier between the air and the tire polymer. A white powder-like
coating forms on the rubber
surface. This is called “blooming”. When
tires are parked for extended periods, blooming does not occur and
ozone
starts attacking the tire polymer. With UV light and ozone
working in concert, the degradation is accelerated
resulting in
drying, discoloration and cracking.
In addition to
nature attacking the tires and rubber trim, man has developed his
own way to add to that:
Rubber/Vinyl Dressings. While the intended
purpose for these chemicals was to protect the rubber as well as add
competitive absorbers, many of today’s dressings do nothing more
than provide a short term greasy shine (they are
usually clear and
greasy similar to baby oil). They are usually a mix of
kerosene/mineral spirits and dimethyl silicone oil. These petroleum
distillates act to strip away the protective waxes from the tires
and not only do nothing
to protect the surface, but actually degrade
it. Dressings come in two flavors, solvent based and water based. As
a
rule of thumb, solvent based dressings last longer, but the new
generation of water-based dressings has durability
approaching those
of the solvent based. If you choose a solvent based dressing, choose
one with a highly refined
grade mineral spirit; this allows it to
dry quickly before it can attack the protective waxes and polymers.
Also if
choosing a dressing with silicone content, make sure that
the dressing contains “good” silicone (of the amino or
siloxane
functional family). These are “non-migratory” or “dry”. And finally,
make sure the dressing you choose
does not contain formaldehyde
(yes, as in funeral home).
Now let’s look at
how we can maintain our tires and trim. The first step to stabilize
the compound and reclaim the
original tire luster is a thorough tire
cleaning. Select a nonacid (“basic” pH >7.0) wheel cleaner or a
natural citrus
based degreaser. Also, use a soft, flexible wheel
brush with natural tampico bristles (in case it comes in contact
with
the wheel surface) to get the full effectiveness of these
cleaners. By the way, if you’ve just mounted new tires on
your car,
you must first remove the mold release agent or else your dressing
won’t absorb (this leads to short
durability and splotchiness of the
dressing). The mold release agent is similar to the wax on wax paper
and must be
dissolved with a solvent based cleaner followed by a
“basic” wheel cleaner or degreaser. Repeat the procedure until
the
tires are squeaky clean.
The second step to
restore the natural luster is the application of a high quality
rubber dressing containing UV
stabilizers which supplement the
UV-protection action in the carbon black. Although exterior rubber
requires a
very durable dressing, it must not jeopardize the
integrity of the compound. In our shop, we use different
treatments
for the tires as opposed to the rubber trim. Usually, the price of a
dressing gives a hint of the quality of
the dressing. The tires
should have a satin sheen to them when dressed. Also, the dressing
should not be slopped
on as they do at the car wash with a paint
brush so as to sling off all over your car’s paint and the poor guy
behind
you. I can’t tell you the numerous times I have gotten a glob
of some greasy dressing all over my pants while
judging concours
events (needless to say those cars didn’t win – I deducted 2 points
consisting of ½ point for the
excess dressing and 1½ points for the
pants). I recommend applying the dressing with a foam applicator and
storing the applicator in a Zip-Lock bag for future use.
On a related note,
all of the modern cars with flexible bumper covers and side moldings
require a “flex agent” added
to the paint to give it flexibility.
However, this flex agent causes the painted parts to be more porous.
This porosity
leads to the absorption of any of the sling-off of
low-grade petroleum oil dressings which leads to black stains that
are impossible to remove. Even repainting these parts is impossible
and they must be replaced. I know for a fact
that Cadillac had this
issue some time ago and now specify in their manual that they are
not liable for that kind of
damage. I’m sure other car manufacturers
have the same policy.
As always, should
you have any questions or comments, please feel free to contact us
at 1-408-249-1017 or send an
email to [email protected].
May the wind be always at your back and may you achieve your pursuit
of
detailing perfection!
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