Spray-on paint protection
The paint on the leading
edge of car hoods is on the
front line for gravel and sand
damage. Until recently, you only
had two ways to protect the
hood: install a “bra” or apply
paint protection film. Bras are
not only ugly but also lower gas
mileage and trap road grit, which
damages the paint. Paint protection
film looks and works much
better, but professional installation
costs about $500. Now
there's a product that DIYers can
apply to protect against paint
Several companies make this
paint film, but we chose the 3M
Paint Defender product for this
story because it lasts up to a year. It
costs about $25 and contains
enough material to coat the bottom
third of your hood. Find it at any
auto parts store. We asked 3M
product expert Todd Mathes to
walk us through the prep and
You'll also need car-washing
supplies, poly sheeting to cover the
entire car and ground, clean-edge
masking tape and a microfiber
cloth. Or buy the optional installation
kit and a spray trigger. The entire job takes less than
two hours. Here's how it's done.
Prep the vehicle
The engine and hood must be cool
when you apply the product. A hot
engine will heat the hood and
force-dry the spray between coats,
defeating its self-leveling feature.
So check the weather report and
pick a time when it'll be cool, dry
and calm. Park the car in a shaded
area the night before. Then start
the project by washing the car with
car wash soap. Make sure you
remove all traces of bug splatter
and tar. Then rinse and dry
Next, pop the hood and prop it
open about 4 in. with a roll of paper
towels or a block of wood.
Tarp, tape and wax
1 of 2
Photo 1: Tape the poly sheeting to the hood
Carefully apply the first layer and then the second layer directly below it. Make the second tape line as straight as possible, and press down along the edge to seal it to the hood as you apply. Double over one end of the tape to make a peel tab.
2 of 2
Photo 2: Wax the exposed hood area
Squirt a dollop of wax onto the hood and work it in with a microfiber towel.
Continue wiping until the surface is free of haze.
Spread a poly sheet over the entire
vehicle. Then spread sheeting on
the ground to catch any overspray.
Starting at the grille, use a scissors
to cut straight up the center of the
poly, stopping about 18 in. from the
bottom edge of the hood. Then cut
right and left out to the fenders
until you have formed a “T” cutout.
Tuck the flaps under the hood and
tape them inside the engine compartment
to prevent them from
moving while you spray. Secure the
rest of the sheeting to the car and
floor with tape to prevent it from
blowing onto the wet finish.
Next, tape the top of the “T” to
the hood. Apply another layer of
tape to form the clean edge
between the spray film and the rest
of the hood (Photo 1). Once the poly
is in place, apply the synthetic wax
included with the product (Photo 2).
Waxing is an important step to
make removal easier a year from
now. So even if you've recently
waxed the car, do it again using the
wax packet included with the
Apply the coating
1 of 2
Photo 3: Spray the hood with protectant
Starting at the tape line and spraying down to the bottom edge of the hood, spray
the product continuously in alternating left to right rows at the rate of two seconds
per foot. Overlap each row slightly. Immediately spray a second layer, moving up and down over the same section. Then apply a third coat in the side-to-side pattern.
2 of 2
Photo 4: Remove the tape while the spray is wet
Grab the doubled-over peel tab and pull the clean-edge tape up and away
from the wet edge.
Shake the can of 3M Paint Defender for a full minute
before applying. Then hold the
nozzle 6 to 8 in. from the hood and
apply three coats to one-half of the
hood (Photo 3). Spray all three coats
in one continuous motion (don't stop and start at the ends of each
row or coat). Move the can at the
rate of six seconds per pass.
Continue spraying onto the fender,
over and above the tape line, and
below the bottom edge of the hood
to get a uniform film thickness at
the edges. A proper application of the paint protection film
should have an “orange peel” texture
and a slightly milky look. Don't
worry—the product self-levels
and dries clear. Then spray
the second half of the hood. When
you're done, remove the clean-edge
tape while the spray is still wet
Park the car in the sun and let it
dry for two to four hours. The film
cures fully in one to four days,
depending on the air temperature
- If bugs or leaves land on the wet
spray, pluck them off immediately
with a pair of tweezers.
- If the spray is solid white, has
lumps or develops sags, you've
applied too much. Stop spraying
and let the product dry. Then peel it
off and start over, moving a bit
faster and applying less product.
- If the wet spray has a “dry” look
or you've missed areas or pinholes,
you can apply more product. But do
it quickly. You only have a
10-minute window. Wait too long
and the product loses its self-leveling
quality and you can wind up
with a textured look.
A year from now
1 of 1
Photo 5: After a year, peel off the film
Lift up a top corner and pull the paint protection film down toward the bottom of the hood
to release as large a piece as possible. Then use both hands to pull the old
film up and across the hood. Wipe the excess off the edges with a rag. Apply
a fresh layer of protection film following the steps shown.
Our expert says that the film can
last a bit longer than one year but
may yellow from UV exposure.
However, the longer you wait, the
harder it is to remove, so don't push
your luck. Pop the hood and peel
the film loose around all three
edges using your fingernail. Then
remove all the film (Photo 5).