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Looking Good: Techniques for Finishing Your Car
By Randy Davis

(An update of an article originally published January 8, 2003)

Have you seen a car on the staging table that caused your jaw to drop
from admiration? The paint job looks like it came right out of a
custom body shop, and other details like decals and accessories look
fabulous. You ask yourself: "How did they do that?"

I won't kid you - I oftentimes ask that question as well. Clearly,
some folks know how to take the finish work to a level beyond most of
us. However, I can share with you some basic techniques for putting a
nice finish on your car. The main tasks to be addressed are filling,
sanding, priming, painting, and decal work.

It is very difficult to create a car of any intricacy without a gouge
or nick that is too deep to sand out. For small defects, the simple
cure is wood putty (or "Bondo" - a car body filler). Press enough of
the product into the defect to completely fill the defect with some
excess. If desired, you can smooth the putty with a finger dipped in
tap water. Allow the putty to dry thoroughly. If the putty sinks or
cracks, apply more putty and let it dry again.

For large defects (e.g., a hole drilled the wrong place), cut a piece
of wood to fill as much of the defect as possible and glue it in
place. After it dries fill any remaining voids with putty, and let it

Next, it is time to proceed to ...

As you probably know, sanding involves smoothing the car, starting
with a coarse grit paper and progressing towards a fine grit paper. A
good grit progression is 60, 120, 240, and 400. This can of coarse
vary, but the ultimate goal is to create a very smooth finish, free of
defects and scratches.

Sanding flat surfaces is greatly simplified by using a sanding block.
A sanding block is designed to hold 1/4 of a sheet of standard
sandpaper. It has a padded surface which helps make the finish very
smooth. When selecting a sanding block, try to find one that can be
easily held by your child (not too wide or heavy).

Figure 1 - Sanding Block

For sanding concave (inward curving) shapes wrap some sandpaper around
a piece of wood (or your finger). A dowel rod or a piece of broom
stick works well for sanding concave curves.

Figure 2 - Concave Curves

Figure 3 - Convex Curves

For convex (outward curving) shapes, use a sanding block, or just hold
the paper in your hand and use fingertip pressure to sand the desired

After the sanding is complete, remove all dust with a vacuum and/or
soft rag. Then create a handle for painting. Two alternatives

- Inserting a dowel rod into a weight hole

- Inserting a long wood/dry wall screw into the bottom of the car -
you might be able to insert the screw into a weight hole so that the
screw hole doesn't show, but be careful to not go all the way through
the car.

Next, I recommend masking off the axle slots (if you have axle holes,
then insert round toothpicks into the holes. This makes future axle
insertion much easier.

Before priming, locate a place for the car to dry. We have a piece of
wire strung under a shelf in the shop, with some binder clips attached
to the line. When we use a screw as a paint handle, the binder clip
can be clipped to the screw, allowing the car to hang upside down to
dry. If you use a dowel rod as a handle, drill an appropriate sized
hole in a workbench, or in a heavy piece of wood. The dowel can then
be fitted into the hole while the car dries.

When spray painting, make sure to wear eye protection and a breathing
mask. Then cover the hand that will hold the car with a plastic bag,
secured with a rubber band. Paint in a well-ventilated, dust and wind
free location. Also watch out that the over spray doesn't get on
something important (cars, walls, etc.). We have large plastic garbage
cans, so we flip up the lid and use it as a backdrop for painting.
Optionally, a large box can be set on end to serve as a backdrop.

The selection of the type of primer is important. I have had the most
success with a "high-build" or "filler-primer", such as that offered
by "Rust-Oleum" and sold at auto parts stores. This type of primer
tends to fill in the pores of the wood, minimizing the number of
primer coats required. If the sanding job is done well, generally
three to four coats are sufficient.

When spraying the primer, keep the can moving and apply light coats.
If you go too heavy, you will get runs that must be sanded out.

Let each primer coat dry, then sand with 600 grit paper and recoat.
If you find a spot that doesn't fill in well, you can apply a little
wood filler or Bondo, sand, and continue priming. Once the car body
is completely smooth, you can proceed to applying the color.

There are many types and brands of spray paint. I strongly recommend
acrylic lacquer paint such as "Dupli-Color - Perfect Match" (auto
parts store item). This type of paint dries quickly, and can be
recoated at any time. Watch out for brands that "can be recoated
within 1 hour or after 24 hours". What happens if you recoat after,
say, three hours? Trust me on this one, you don't want to know.

I also suggest avoiding enamel paints. Enamel paints generally take a
long time (many days) to cure, are very susceptible to finger prints,
and act like a graphite magnet.

Generally two or three color coats will be sufficient. After the last
coat allow the car to dry thoroughly. Then proceed to adding decals,
pin striping, etc., and finally apply clear coats.

Decorations are certainly not required, but that can really dress up a
car. They also have a practical use; they can cover up any defects in
the paint job. We'll discuss dry transfer decals, stick-on decals
(includes stickers) and pin-striping. All of these products are
available at Maximum Velocity.

Dry-Transfer Decals

Dry-Transfer decals are available in lots of designs, many of which
are targeted at pinewood derby car builders.

Figure 4 - Dry Transfer Decal

The best dry-transfer decals are very thin and do not have a clear
edge. Thus, they blend in to the paint such that you have to look
closely to see that the design is actually a decal.

To apply dry-transfer decals, cut out the desired design, place it on
the car in the desired location, hold it down, and use a soft pencil
with a rounded tip to scribble over the entire decal (you will
actually be scribbling on the transfer material, not the actual
decal). After scribbling over the entire decal, carefully lift up on
the transfer material. If the decal is not completely detached from
the transfer material, scribble some more and try again. After the
transfer material is removed, take the provided tissue-like paper and
rub it over the entire decal.

Stick-on Decals

Stick-on decals, as well as stickers are also good choices. These
apply much easier than dry-transfer decals, but make sure you put it
where you want it. As you know, stickers like to attach themselves
where you don't want them!

Figure 5 - Sticker Decal

My daughter used stickers to decorate her Diamondbacks car; she found
the stickers at a team shop. I believe that team stickers exist for
every professional team, as well as most college teams.

Figure 6 - D-Backs Car

Home Made Stickers

Can't find what you want, or on a budget? Make your own stickers! Find
a photo, a logo, or most anything on paper. Cut it out, apply some
glue, and place it on the car. We used a Hershey's chocolate bar
wrapper to decorate this regatta boat.

Figure 7 - Homemade Sticker

Pin Striping
I am a big fan of pin striping; it is relatively inexpensive, easy to
apply, and can really dress up a car. Pin striping is long, thin,
colored tape that has an adhesive backing. It adapts well to curves
in the car and can be mixed and matched, both in color and in width.

Figure 8 - Yellow Pin Striping (1/4 and 1/8 inch)

To apply pin striping, unroll a piece longer than you need, pull it
taut and then apply it to the car. Use a piece of tissue paper (not
Kleenex, but the kind used in gift bags) to press down on the pin
striping. This will eliminate any air bubbles and ensures that it is
pressed down well. After the pin striping is in place, trim the excess
off the ends with a sharp knife (hobby knife or razor knife). If the
pin striping will be placed on the front and/or back of the car (as in
Figure 7), wrap the pin striping under the car and trim it off
underneath. This makes for a much cleaner finish.

All decorated? Now it is time to protect your investment and give a
deep glossy look. Applying multiple clear coats will not only improve
the appearance, but will (mostly) protect the car from finger prints,
graphite and minor scratches. Make sure to select a clear coat that is
compatible with the paint you used. If you used Dupli-Color for the
color, then use Dupli-Color Clear Coat. I recommend at least five
coats of clear. Fortunately it dries very quickly, so you can apply
the coats in a fairly short period of time.

I have barely covered this subject as there are certainly other
options for painting and decorating your car. If you have a technique
you would like to share, please send it to me, and I'll try to include
a number of reader ideas in a future article.

From Pinewood Derby Times Volume 11, Issue 5

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