A good masking job provides the underpinnings for a successful
paint job; a poor masking job, on the other hand, can result in
the frustration of paint-refinishing problems.
The purpose of masking is to minimize flaws, such as paper fibers,
solvent penetration, paint-overspray mist and paint flaking that
can ruin your paint job. As vehicle prices continue to increase,
body shop customers are more and more demanding in their expectations:
They want a flawless finish when you hand them back the key to
Fortunately, aftermarket manufacturers continue to develop new
and enhanced masking products and systems to better help you provide
total customer satisfaction. Today, there’s an effective way for
accomplishing virtually every masking application, and the following
information sheds light on these new approaches.
Hoods, Trunks and Doors
To outline hoods, trunks and door areas prior to refinishing,
use a high-quality, professional masking tape in conjunction with
Always use a high-quality masking paper on the paint edge of these
types of operations to eliminate solvent penetration, fiber contamination
and paint flaking. Plastic masking films also provide an excellent
barrier against particle contaminants. Note: Masking films that
cling to the surface deliver the best results.
Another option is overspray masking liquid in either a wet or
dry formula. Overspray masking liquids are easy to apply to clean
up. When using the dry formula, be sure to apply an even coat,
and allow it to dry before proceeding with the refinish job.
Whichever brand of overspray masking liquid you use, once it’s
dry, you’ll want to outline the area to be painted with masking
tape and 12- or 18-inch high-quality masking paper.
Jambs, Gas Caps and Openings
Masking jambs, gas caps and other pesky openings to prevent compound
sling from marring the paint is easier than ever with the newer
door-aperture refinish tapes on the market. These foam-like tapes
are labor-saving ways to prevent contamination.
Before applying a foamy door-aperture tape, always wipe clean
the area to be taped with a solvent. Then apply the tape about
3/16 of an inch back from the area to be painted. Don’t stretch
the tape while applying it. Once the tape is applied, firmly press
it into place to ensure adhesion.
A soft paint edge can be obtained by back-taping over the area
requiring protection with 2-inch masking tape. Multiple 3/4-inch
strips of professional masking tape, combined with 6-inch masking
paper, also can be employed to keep overspray from entering interior
Another fast and effective method for protecting door jambs and
other openings is to apply a coat of overspray masking liquid.
Grills and Bumpers
You can provide overspray protection on automotive grills and
bumpers two different ways.
The traditional way is to cover the targeted surface with a combination
of high-quality paper and masking tape. Prefolded masking film
in 4-inch widths is also effective and generally provides just
the right amount of coverage. When film is used, also apply masking
paper for additional protection along the paint edge.
Windows and Windshields
For a defined paint line and effective overspray protection on
windows and windshields, cover the glass area by taping down two
pieces of masking paper, overlapping the bottom masking-paper
layer with the top layer. Or, use either dry or wet overspray
masking liquid to cover the glass.
Also, a variety of products on the market are designed to lift
up the molding around automotive glass – specifically windshields
and back lights – and allow paint to flow under the molding. The
result is a better paint job, making the repaint work less obvious.
Plastic masking film also effectively prevents overspray contamination.
Wheel Wells and Tires
Using the appropriate technique for covering wheel wells and tires
is critical to obtaining a perfect paint job. Canvas covers, newspapers
and other traditional materials can collect dust and release it
into the air during painting. A better approach is to use 2-inch
and 4-inch plastic film to cover chrome moldings and to provide
protection in the wheel wells and on the tires.
Masking paper is always an option for masking wheel wells. To
mask tires with masking paper, first wet the paper and then drape
it around the tire. When the paper dries, it will conform to the
Wet-formula overspray masking liquid is another effective alternative
for protecting wheel wells and tires.
Mirrors and Hardware
Outside mirrors can be masked with 2-inch masking tape or with
a combination of 6-inch masking paper and tape. To trap dirt and
dust that could drift onto the freshly painted surface, apply
a coat of overspray masking liquid to the mirrors and other hardware.
For detailed masking of key holes and other hardware – and to
obtain a clean paint line – use an appropriately thin plastic
tape that conforms to hardware contours.
Lights, Reflectors and Moldings
Lights and reflectors can be masked with strips of professional
automotive masking tape. Use 2-inch-wide strips of masking tape
to protect headlights, and when a distinct paint line is required,
outline the paint edge with a thin plastic tape and overmask with
standard masking tape.
Lights can also be protected with a coating of wet or dry overspray
Graphics and Ornamentation
Letters, emblems and most types of ornaments can be masked with
standard professional masking tape or with a fine-line plastic
tape, depending on the job. Existing stripes on vehicles can be
protected from overspray with the application of a fine-line tape.
When painting pinstripes, refinishers can choose from a variety
of products. Precut striping tapes, available in different widths,
can be applied to achieve crisp, clean stripes. With pull-out
tapes, you can mask the entire area to be striped, and then pull
away the precut strips to reveal the surface where the paint stripes
will be applied. When using pull-out tapes, remember not to press
the tape into place along the vehicle surface. Instead, lay the
strip of tape down lightly, and pull off the strips as desired.
For the best results with detail painting such as this, choose
striping tapes designed specifically not to stick to the freshly
When the job calls for making open areas – such as windows and
trunks – secure against overspray, you can use 6-inch strips of
quality masking paper and standard masking tape. Another option
is to use strips of 4-foot plastic masking film for effective
When working on pickup trucks, 6-foot plastic masking film is
ideal for masking off truck beds in one pass. Overspray masking
liquid is also a quick and effective product for masking open
If you know the vehicle will be exposed to the outdoors during
the refinish job, use a special weather-resistant masking tape
and plastic masking film to ensure interior protection. A good-quality,
weather-resistant masking tape will survive up to 30 days of outdoor
Several approaches can be taken to mask engine compartments.
Masking paper and masking tape or masking film and tape are both
suited for protecting engine compartments from overspray. For
larger jobs, such as RVs and semis, masking films are available
in many larger sizes.
Don’t Get Left in the Dust
Automotive masking is both an art and a science: The art is in
the technique of applying the materials, while the science is
in the materials themselves.
To achieve a quality paint job, always use the best masking materials
on the market; inferior materials can result in hidden shop costs
that end up being a sharp drain on profits. In today’s competitive
world, how many $500 paint jobs can you afford to redo before
your competition leaves you in the dust?
By understanding which masking systems to use when, you’ll not
only perfect your paint work, but also help your shop become more
efficient – and more profitable – in the future.
Cleanup Tips for Overspray Masking Liquids
One of the great advantages of overspray masking liquids is their
ease of disposal.
Wet-formula overspray masking liquid can be washed off vehicles
with plain water from a garden hose or with a pressure washer.
As the overspray masking liquid disappears down the drain, so
does the dust, dirt and other contaminants that it collected while
protecting the vehicle.
To clean up dry-formula overspray masking liquid, first rinse
the vehicle with water and then allow one to two minutes for the
overspray masking liquid to dissolve. Wash the car as you normally
Writer Dan Puls is the market development manager, masking products,
at 3M Automotive Trades Division.